Michael J. Overman

Metastatic DNA mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) colorectal cancer has a poor prognosis after treatment with conventional chemotherapy and exhibits high levels of tumour neoantigens, tumour-infiltrating lymphocytes, and checkpoint regulators. All of these features are associated with the response to PD-1 blockade in other tumour types. Therefore, we aimed to study nivolumab, a PD-1 immune checkpoint inhibitor, in patients with dMMR/MSI-H metastatic colorectal cancer.In this ongoing, multicentre, open-label, phase 2 trial, we enrolled adults (aged ≥18 years) with histologically confirmed recurrent or metastatic colorectal cancer locally assessed as dMMR/MSI-H from 31 sites (academic centres and hospitals) in eight countries (Australia, Belgium, Canada, France, Ireland, Italy, Spain, and the USA). Eligible patients had progressed on or after, or been intolerant of, at least one previous line of treatment, including a fluoropyrimidine and oxaliplatin or irinotecan. Patients were given 3 mg/kg nivolumab every 2 weeks until disease progression, death, unacceptable toxic effects, or withdrawal from study. The primary endpoint was investigator-assessed objective response as per Response Evaluation Criteria in Solid Tumors (version 1.1). All patients who received at least one dose of study drug were included in all analyses. This trial is registered with ClinicalTrials.gov, number NCT02060188.Of the 74 patients who were enrolled between March 12, 2014, and March 16, 2016, 40 (54%) had received three or more previous treatments. At a median follow-up of 12·0 months (IQR 8·6-18·0), 23 (31·1%, 95% CI 20·8-42·9) of 74 patients achieved an investigator-assessed objective response and 51 (69%, 57-79) patients had disease control for 12 weeks or longer. Median duration of response was not yet reached; all responders were alive, and eight had responses lasting 12 months or longer (Kaplan-Meier 12-month estimate 86%, 95% CI 62-95). The most common grade 3 or 4 drug-related adverse events were increased concentrations of lipase (six [8%]) and amylase (two [3%]). 23 (31%) patients died during the study; none of these deaths were deemed to be treatment related by the investigator.Nivolumab provided durable responses and disease control in pre-treated patients with dMMR/MSI-H metastatic colorectal cancer, and could be a new treatment option for these patients.Bristol-Myers Squibb.

Purpose Nivolumab provides clinical benefit (objective response rate [ORR], 31%; 95% CI, 20.8 to 42.9; disease control rate, 69%; 12-month overall survival [OS], 73%) in previously treated patients with DNA mismatch repair–deficient (dMMR)/microsatellite instability–high (MSI-H) metastatic colorectal cancer (mCRC); nivolumab plus ipilimumab may improve these outcomes. Efficacy and safety results for the nivolumab plus ipilimumab cohort of CheckMate-142, the largest single-study report of an immunotherapy combination in dMMR/MSI-H mCRC, are reported. Patients and Methods Patients received nivolumab 3 mg/kg plus ipilimumab 1 mg/kg once every 3 weeks (four doses) followed by nivolumab 3 mg/kg once every 2 weeks. Primary end point was investigator-assessed ORR. Results Of 119 patients, 76% had received ≥ two prior systemic therapies. At median follow-up of 13.4 months, investigator-assessed ORR was 55% (95% CI, 45.2 to 63.8), and disease control rate for ≥ 12 weeks was 80%. Median duration of response was not reached; most responses (94%) were ongoing at data cutoff. Progression-free survival rates were 76% (9 months) and 71% (12 months); respective OS rates were 87% and 85%. Statistically significant and clinically meaningful improvements were observed in patient-reported outcomes, including functioning, symptoms, and quality of life. Grade 3 to 4 treatment-related adverse events (AEs) occurred in 32% of patients and were manageable. Patients (13%) who discontinued treatment because of study drug-related AEs had an ORR (63%) consistent with that of the overall population. Conclusion Nivolumab plus ipilimumab demonstrated high response rates, encouraging progression-free survival and OS at 12 months, manageable safety, and meaningful improvements in key patient-reported outcomes. Indirect comparisons suggest combination therapy provides improved efficacy relative to anti–programmed death-1 monotherapy and has a favorable benefit-risk profile. Nivolumab plus ipilimumab provides a promising new treatment option for patients with dMMR/MSI-H mCRC.

Fluorouracil/leucovorin as the sole therapy for metastatic colorectal cancer (CRC) provides an overall survival of 8 to 12 months. With an increase in surgical resections of metastatic disease and development of new chemotherapies, indirect evidence suggests that outcomes for patients are improving in the general population, although the incremental gain has not yet been quantified.We performed a retrospective review of patients newly diagnosed with metastatic CRC treated at two academic centers from 1990 through 2006. Landmark analysis evaluated the association of diagnosis year and liver resection with overall survival. Additional survival analysis of the Surveillance Epidemiology and End Results (SEER) database evaluated a similar population from 1990 through 2005.Two thousand four hundred seventy patients with metastatic CRC at diagnosis received their primary treatment at the two institutions during this time period. Median overall survival for those patients diagnosed from 1990 to 1997 was 14.2 months, which increased to 18.0, 18.6, and 29.3 months for patients diagnosed in 1998 to 2000, 2001 to 2003, and 2004 to 2006, respectively. Likewise, 5-year overall survival increased from 9.1% in the earliest time period to 19.2% in 2001 to 2003. Improved outcomes from 1998 to 2004 were a result of an increase in hepatic resection, which was performed in 20% of the patients. Improvements from 2004 to 2006 were temporally associated with increased utilization of new chemotherapeutics. In the SEER registry, overall survival for the 49,459 identified patients also increased in the most recent time period.Profound improvements in outcome in metastatic CRC seem to be associated with the sequential increase in the use of hepatic resection in selected patients (1998 to 2006) and advancements in medical therapy (2004 to 2006).

This selection from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Colon Cancer focuses on systemic therapy options for the treatment of metastatic colorectal cancer (mCRC), because important updates have recently been made to this section. These updates include recommendations for first-line use of checkpoint inhibitors for mCRC, that is deficient mismatch repair/microsatellite instability-high, recommendations related to the use of biosimilars, and expanded recommendations for biomarker testing. The systemic therapy recommendations now include targeted therapy options for patients with mCRC that is HER2-amplified, or BRAF V600E mutation-positive. Treatment and management of nonmetastatic or resectable/ablatable metastatic disease are discussed in the complete version of the NCCN Guidelines for Colon Cancer available at NCCN.org. Additional topics covered in the complete version include risk assessment, staging, pathology, posttreatment surveillance, and survivorship.

The primary goal of this study was to evaluate whether pathologic response to chemotherapy predicts patient survival after preoperative chemotherapy and resection of colorectal liver metastases (CLM). The secondary goal of the study was to identify the clinical predictors of pathologic response.A retrospective review was performed of 305 patients who underwent preoperative irinotecan- or oxaliplatin-based chemotherapy, followed by resection of CLM. Pathologic response was systematically evaluated and reported as the mean of the percentage of cancer cells remaining within each tumor. Univariate and multivariate analyses were performed to identify the predictors of pathologic response and survival.Cumulative 5-year overall survival rates by pathologic response status were as follows: 75% complete response (no residual cancer cells), 56% major response (1% to 49% residual cancer cells), and 33% minor response (> or = 50% residual cancer cells; complete v major response, P = .037; major v minor response, P = .028). Multivariate analysis revealed that only surgical margin status (P = .050; hazard ratio [HR], 1.77) and pathologic response (major response: P = .034; HR, 4.80; minor response: P = .007; HR, 6.93) were independent predictors of survival. Multivariate analysis of the predictors of pathologic response revealed that carcinoembryonic antigen level < or = 5 ng/mL, tumor size < or = 3 cm, and chemotherapy with fluoropyrimidine plus oxaliplatin and bevacizumab were independent predictors of pathologic response.Pathologic response predicts survival after preoperative chemotherapy and resection of CLM. Degree of pathologic response represents a new outcome end point for prognosis after resection of CLM.

We investigated the efficacy of fluorouracil (FU), leucovorin, irinotecan, and bevacizumab (FOLFIRI + B) in a phase II trial in patients previously untreated for metastatic colorectal cancer (mCRC), and changes during treatment in plasma cytokines and angiogenic factors (CAFs) as potential markers of treatment response and therapeutic resistance.We conducted a phase II, two-institution trial of FOLFIRI + B. Each 14-day cycle consisted of bevacizumab (5 mg/kg), irinotecan (180 mg/m(2)), bolus FU (400 mg/m(2)), and leucovorin (400 mg/m(2)) followed by a 46-hour infusion of FU (2,400 mg/m(2)). Levels of 37 CAFs were assessed using multiplex-bead assays and enzyme-linked immunosorbent assay at baseline, during treatment, and at the time of progressive disease (PD).Forty-three patients were enrolled. Median progression-free survival (PFS), the primary end point of the study, was 12.8 months. Median overall survival was 31.3 months, with a response rate of 65%. Elevated interleukin-8 at baseline was associated with a shorter PFS (11 v 15.1 months, P = .03). Before the radiographic development of PD, several CAFs associated with angiogenesis and myeloid recruitment increased compared to baseline, including basic fibroblast growth factor (P = .046), hepatocyte growth factor (P = .046), placental growth factor (P < .001), stromal-derived factor-1 (P = .04), and macrophage chemoattractant protein-3 (P < .001).Efficacy and tolerability of FOLFIRI + B appeared favorable to historical controls in this single arm study. Before radiographic progression, there was a shift in balance of CAFs, with a rise in alternate pro-angiogenic cytokines and myeloid recruitment factors in subsets of patients that may represent mechanisms of resistance.

Exosomes arise from viable cancer cells and may reflect a different biology than circulating cell-free DNA (cfDNA) shed from dying tissues. We compare exosome-derived DNA (exoDNA) to cfDNA in liquid biopsies of patients with pancreatic ductal adenocarcinoma (PDAC).Patient samples were obtained between 2003 and 2010, with clinically annotated follow up to 2015. Droplet digital PCR was performed on exoDNA and cfDNA for sensitive detection of KRAS mutants at codons 12/13. A cumulative series of 263 individuals were studied, including a discovery cohort of 142 individuals: 68 PDAC patients of all stages; 20 PDAC patients initially staged with localized disease, with blood drawn after resection for curative intent; and 54 age-matched healthy controls. A validation cohort of 121 individuals (39 cancer patients and 82 healthy controls) was studied to validate KRAS detection rates in early-stage PDAC patients. Primary outcome was circulating KRAS status as detected by droplet digital PCR. Secondary outcomes were disease-free and overall survival.KRAS mutations in exoDNA, were identified in 7.4%, 66.7%, 80%, and 85% of age-matched controls, localized, locally advanced, and metastatic PDAC patients, respectively. Comparatively, mutant KRAS cfDNA was detected in 14.8%, 45.5%, 30.8%, and 57.9% of these individuals. Higher exoKRAS MAFs were associated with decreased disease-free survival in patients with localized disease. In the validation cohort, mutant KRAS exoDNA was detected in 43.6% of early-stage PDAC patients and 20% of healthy controls.Exosomes are a distinct source of tumor DNA that may be complementary to other liquid biopsy DNA sources. A higher percentage of patients with localized PDAC exhibited detectable KRAS mutations in exoDNA than previously reported for cfDNA. A substantial minority of healthy samples demonstrated mutant KRAS in circulation, dictating careful consideration and application of liquid biopsy findings, which may limit its utility as a broad cancer-screening method.

<h3>Importance</h3> Representative racial/ethnic participation in research, especially in clinical trials that establish standards of care, is necessary to minimize disparities in outcomes and to uphold societal equity in health care. <h3>Objective</h3> To evaluate the frequency of race reporting and proportional race representation in trials supporting US Food and Drug Administration (FDA) oncology drug approvals. <h3>Design, Setting, and Participants</h3> Database study of all reported trials supporting FDA oncology drug approvals granted between July 2008 and June 2018. Primary reports of trials were obtained from PubMed and ClinicalTrials.gov. Food and Drug Administration approvals were identified using the FDA archives. The US population-based cancer estimates by race were calculated using National Cancer Institute–Surveillance, Epidemiology, and End Results and US Census databases. <h3>Main Outcomes and Measures</h3> Primary outcomes were the proportion of trials reporting race and the proportion of patients by race participating in trials. Secondary outcomes included race subgroup analyses reporting and gaps between race proportion in trials and the US population. Descriptive statistics, Fisher exact, and χ²tests were used to analyze the data. Proportions and odds ratios (OR) with 95% CIs were reported. <h3>Results</h3> Among 230 trials with a total of 112 293 participants, 145 (63.0%) reported on at least 1 race, 18 (7.8%) documented the 4 major races in the United States (white, Asian, black, and Hispanic), and 58 (25.2%) reported race subgroup analyses. Reporting on white, Asian, black, and Hispanic races was included in 144 (62.6%), 110 (47.8%), 88 (38.2%), and 23 (10.0%) trials, respectively. Between July 2008 and June 2013 vs July 2013 and June 2018, the number of trials reporting race (45 [56.6%] vs 100 [67.1%]; OR, 1.63; 95% CI, 0.93-2.87;<i>P</i> = .09) and race subgroup analysis (13 [16.1%] vs 45 [30.2%]; OR, 2.26, 95% CI, 1.16-4.67;<i>P</i> = .03) changed minimally and varied across races. Whites, Asians, blacks, and Hispanics represented 76.3%, 18.3%, 3.1% and 6.1% of trial participants, respectively, and the proportion for each race enrolled over time changed nominally (blacks, 3.6% vs 2.9% and Hispanics, 5.3% vs 6.7%) from July 2008 to June 2013 vs July 2013 to June 2018. Compared with their proportion of US cancer incidence, blacks (22% of expected) and Hispanics (44% of expected) were underrepresented compared with whites (98% of expected) and Asians (438% of expected). <h3>Conclusions and Relevance</h3> Race and race subgroup analysis reporting occurs infrequently, and black and Hispanic races are consistently underrepresented compared with their burden of cancer incidence in landmark trials that led to FDA oncology drug approvals. Enhanced minority engagement is needed in trials to ensure the validity of results and reliable benefits to all.

The biological functions and mechanisms of oncogenic KRASG12D (KRAS∗) in resistance to immune checkpoint blockade (ICB) therapy are not fully understood. We demonstrate that KRAS∗ represses the expression of interferon regulatory factor 2 (IRF2), which in turn directly represses CXCL3 expression. KRAS∗-mediated repression of IRF2 results in high expression of CXCL3, which binds to CXCR2 on myeloid-derived suppressor cells and promotes their migration to the tumor microenvironment. Anti-PD-1 resistance of KRAS∗-expressing tumors can be overcome by enforced IRF2 expression or by inhibition of CXCR2. Colorectal cancer (CRC) showing higher IRF2 expression exhibited increased responsiveness to anti-PD-1 therapy. The KRAS∗-IRF2-CXCL3-CXCR2 axis provides a framework for patient selection and combination therapies to enhance the effectiveness of ICB therapy in CRC.

Purpose Prolonged survival after two-stage resection (TSR) of advanced colorectal liver metastases (CLM) may be the result of selection of best responders to chemotherapy. The impact of complete resection in this well-selected group is controversial. Patients and Methods Data on 890 patients undergoing resection and 879 patients who received only chemotherapy for CLM were collected prospectively. We used intent-to-treat analysis to evaluate the survival of patients who underwent TSR. Additionally, we evaluated a cohort of nonsurgically treated patients selected to mirror the TSR population: colorectal metastases with liver-only disease, objective response to chemotherapy, and alive 1 year after chemotherapy initiation. Results Sixty-five patients underwent the first stage of TSR; 62 patients fulfilled the inclusion criteria for the medical group. TSR patients had a mean of 6.7 ± 3.4 CLM with mean size of 4.5 ± 3.1 cm. Nonsurgical patients had a mean of 5.9 ± 2.9 CLM with mean size of 5.4 ± 3.4 cm (not significant). Forty-seven TSR patients (72%) completed the second stage. Progression between stages was the main cause of noncompletion of the second stage (61%). After 50 months median follow-up, the 5-year survival rate was 51% in the TSR group and 15% in the medical group (P = .005). In patients who underwent TSR, noncompletion of TSR and major postoperative complications were independently associated with worse survival. Conclusion TSR is associated with excellent outcome in patients with advanced CLM as a result of both selection by chemotherapy and complete resection of metastatic disease.

The NCCN Guidelines for Rectal Cancer provide recommendations for the diagnosis, evaluation, treatment, and follow-up of patients with rectal cancer. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines. These updates include clarifying the definition of rectum and differentiating the rectum from the sigmoid colon; the total neoadjuvant therapy approach for localized rectal cancer; and biomarker-targeted therapy for metastatic colorectal cancer, with a focus on new treatment options for patients with BRAF V600E- or HER2 amplification-positive disease.

Nivolumab received US Food and Drug Administration approval as a single agent or in combination with ipilimumab in patients with microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC) that progressed following treatment with a fluoropyrimidine, oxaliplatin, and irinotecan based on CheckMate 142. Presented are results of nivolumab plus low-dose ipilimumab in the first-line therapy cohort from the phase II CheckMate 142 study.Patients with no prior treatment in the metastatic setting for MSI-H/dMMR CRC were treated with nivolumab every 2 weeks plus low-dose ipilimumab every 6 weeks until disease progression. The primary end point was objective response rate (investigator assessment; RECIST v1.1).Median age of treated patients was 66 years (N = 45). Median follow-up was 29.0 months. Objective response rate and disease control rate were 69% (95% CI, 53 to 82) and 84% (95% CI, 70.5 to 93.5), respectively, with 13% complete response rate. Median duration of response was not reached; 74% of responders had ongoing responses at data cutoff. Median progression-free survival and median overall survival were not reached with minimum follow-up of 24.2 months (24-month rates, 74% and 79%, respectively). Clinical benefit was observed regardless of baseline demographic and tumor characteristics, including BRAF or KRAS mutation status. In a post hoc analysis, of 14 patients who discontinued treatment and did not receive subsequent therapy, 10 remained progression-free. Patient-reported outcomes were stable over the treatment period. Grade 3-4 treatment-related adverse events occurred in 22% of patients; 13% discontinued because of any-grade treatment-related adverse events.Nivolumab plus low-dose ipilimumab demonstrated robust and durable clinical benefit and was well tolerated as a first-line treatment for MSI-H/dMMR mCRC. Based on these promising data, randomized studies are warranted.

Purpose Although the incorporation of research biopsies into clinical trials is increasing, limited information is available about how study protocols and informed consents integrate and describe their use. Methods All therapeutic clinical trials in which image-guided research biopsies were performed from January 1, 2005, to October 1, 2010, were identified from an interventional radiology database. Data from study protocols and informed consents were extracted and analyzed. Procedural complications were recorded. Results A total of 57 clinical trials were identified, of which 38 (67%) contained at least one mandatory biopsy. The analysis of the research biopsy tumor tissue was a study end point in 95% of trials. The primary indication for a research biopsy was for integral biomarker analysis in 32% and for correlative science in 68% of trials. A statistical analytic plan for the correlative science research biopsy tumor tissue was mentioned in 26%, described as exploratory in 51%, and not mentioned in 23% of trials. For studies with mandatory biopsies, biopsy was an eligibility criterion in 71% of trials, and a statistical justification for the research biopsy sample size was present in 50% of trials. A total of 745 research biopsies were performed on 576 patients. Overall and major complication rates were 5.2% (39 of 745 biopsies) and 0.8% (six of 745 biopsies), respectively. Complication rates for intrathoracic and abdominal/pelvic solid organ biopsies were 17.1% (36 of 211 biopsies) and 1.6% (three of 189 biopsies), respectively. Site-stratified research biopsy–related risks were discussed in five consents. Conclusion A better representation of the risks and benefits of research biopsies in study protocols and informed consents is needed.

Abstract Fibroblast growth factor (FGF) signaling regulates cell proliferation, differentiation, survival, angiogenesis, and wound healing. Compelling evidence for deregulated FGF signaling in tumorigenesis continues to emerge, and a growing body of research suggests that FGF may also play an integral role in the resistance to anti-VEGF therapy. Although agents targeting FGF signaling are early in development, the potential to target both the VEGF and FGF pathways may translate into improvements in the clinical care of cancer patients. Clin Cancer Res; 17(19); 6130–9. ©2011 AACR.

An increasing number of patients with synchronous colorectal liver metastases (CLM) are candidates for resection. The optimal treatment sequence in these patients has not been defined.Data on 156 consecutive patients with synchronous resectable CLM and intact primary were reviewed. Surgical strategies were defined as combined (combined resection of primary and liver), classic (primary before liver), and reverse (liver before primary) after preoperative chemotherapy. Postoperative morbidity and mortality rates and overall survival were analyzed.One hundred forty-two patients (83%) had resection of all disease. Seventy-two patients underwent classic, 43 combined, and 27 reverse strategies. Median numbers of CLMs per patient were 1 in the combined, 3 in the classic, and 4 in the reverse strategy group (p = 0.01 classic vs reverse; p < 0.001 reverse vs combined). Postoperative mortality rates in the combined, classic, and reverse strategies were 5%, 3%, and 0%, respectively (p = NS), and postoperative cumulative morbidity rates were 47%, 51%, and 31%, respectively (p = NS). Three-year and 5-year overall survival rates were, respectively, 65% and 55% in the combined, 58% and 48% in the classic, and 79% and 39% in the reverse strategy (NS). On multivariate analysis, liver tumor size >3 cm (hazard ratio [HR] 2.72, 95% CI 1.52 to 4.88) and cumulative postoperative morbidity (HR 1.8, 95% CI 1.03 to 3.19) were independently associated with overall survival after surgery.The classic, combined, or reverse surgical strategies in patients with synchronous presentation of CLM are associated with similar outcomes. The reverse strategy can be considered as an alternative option in patients with advanced CLM and an asymptomatic primary.

Immune checkpoint therapy (ICT) has transformed cancer treatment in recent years; however, treatment response is not uniform across tumor types. The tumor immune microenvironment plays a critical role in determining response to ICT; therefore, understanding the differential immune infiltration between ICT-sensitive and ICT-resistant tumor types will help to develop effective treatment strategies. We performed a comprehensive analysis of the immune tumor microenvironment of an ICT-sensitive tumor (melanoma, n = 44) and an ICT-resistant tumor (pancreatic cancer, n = 67). We found that a pancreatic tumor has minimal to moderate infiltration of CD3, CD4, and CD8 T cells; however, the immune infiltrates are predominantly present in the stromal area of the tumor and are excluded from tumoral area compared with melanoma, where the immune infiltrates are primarily present in the tumoral area. Metastatic pancreatic ductal adenocarcinomas (PDACs) had a lower infiltration of total T cells compared with resectable primary PDACs, suggesting that metastatic PDACs have poor immunogenicity. Further, a significantly higher number of CD68+ macrophages and VISTA+ cells (also known as V-domain immunoglobulin suppressor of T cell activation) were found in the pancreatic stromal area compared with melanoma. We identified VISTA as a potent inhibitory checkpoint that is predominantly expressed on CD68+ macrophages on PDACs. These data suggest that VISTA may be a relevant immunotherapy target for effective treatment of patients with pancreatic cancer.

Immune checkpoint therapy with anti-CTLA-4 and anti-PD-1/PD-L1 has revolutionized the treatment of many solid tumors. However, the clinical efficacy of immune checkpoint therapy is limited to a subset of patients with specific tumor types1,2. Multiple clinical trials with combinatorial immune checkpoint strategies are ongoing; however, the mechanistic rationale for tumor-specific targeting of immune checkpoints is elusive. To garner an insight into tumor-specific immunomodulatory targets, we analyzed 94 patients representing five different cancer types, including those that respond relatively well to immune checkpoint therapy and those that do not, such as glioblastoma multiforme, prostate cancer and colorectal cancer. Through mass cytometry and single-cell RNA sequencing, we identified a unique population of CD73hi macrophages in glioblastoma multiforme that persists after anti-PD-1 treatment. To test if targeting CD73 would be important for a successful combination strategy in glioblastoma multiforme, we performed reverse translational studies using CD73-/- mice. We found that the absence of CD73 improved survival in a murine model of glioblastoma multiforme treated with anti-CTLA-4 and anti-PD-1. Our data identified CD73 as a specific immunotherapeutic target to improve antitumor immune responses to immune checkpoint therapy in glioblastoma multiforme and demonstrate that comprehensive human and reverse translational studies can be used for rational design of combinatorial immune checkpoint strategies.

The microsatellite instability-high (MSI-H) phenotype, present in 15% of early colorectal cancer (CRC), confers good prognosis. MSI-H metastatic CRC is rare and its impact on outcomes is unknown. We describe survival outcomes and the impact of chemotherapy, metastatectomy, and BRAF V600E mutation status in the largest reported cohort of MSI-H metastatic colorectal cancer (CRC).A retrospective review of 55 MSI-H metastatic CRC patients from two institutions, Royal Melbourne Hospital (Australia) and The University of Texas MD Anderson Cancer Center (United States), was conducted. Statistical analyses utilized Kaplan-Meier method, Log-rank test, and Cox proportional hazards models.Median age was 67 years (20-90), 58% had poor differentiation, and 45% had stage IV disease at presentation. Median overall survival (OS) from metastatic disease was 15.4 months. Thirteen patients underwent R0/R1 metastatectomies, with median OS from metastatectomy 33.8 months. Thirty-one patients received first-line systemic chemotherapy for metastatic disease with median OS from the start of chemotherapy 11.5 months. No statistically significant difference in progression-free survival or OS was seen between fluoropyrimidine, oxaliplatin, or irinotecan based chemotherapy. BRAF V600E mutation was present in 14 of 47 patients (30%). BRAF V600E patients demonstrated significantly worse median OS; 10.1 versus 17.3 months, P = 0.03. In multivariate analyses, BRAF V600E mutants had worse OS (HR 4.04; P = 0.005), while patients undergoing metastatectomy (HR 0.11; P = <0.001) and patients who initially presented as stage IV disease had improved OS (HR 0.27; P = 0.003).Patients with MSI-H metastatic CRC do not appear to have improved outcomes. BRAF V600E mutation is a poor prognostic factor in MSI-H metastatic CRC.

Purpose: Colorectal cancers are classified as right/left-sided based on whether they occur before/after the splenic flexure, with established differences in molecular subtypes and outcomes. However, it is unclear if this division is optimal and whether precise tumor location provides further information.Experimental Design: In 1,876 patients with colorectal cancer, we compared mutation prevalence and overall survival (OS) according to side and location. Consensus molecular subtype (CMS) was compared in a separate cohort of 608 patients.Results: Mutation prevalence differed by side and location for TP53, KRAS, BRAFV600, PIK3CA, SMAD4, CTNNB1, GNAS, and PTEN Within left- and right-sided tumors, there remained substantial variations in mutation rates. For example, within right-sided tumors, RAS mutations decreased from 70% for cecal, to 43% for hepatic flexure location (P = 0.0001), while BRAFV600 mutations increased from 10% to 22% between the same locations (P < 0.0001). Within left-sided tumors, the sigmoid and rectal region had more TP53 mutations (P = 0.027), less PIK3CA (P = 0.0009), BRAF (P = 0.0033), or CTNNB1 mutations (P < 0.0001), and less MSI (P < 0.0001) than other left-sided locations. Despite this, a left/right division preceding the transverse colon maximized prognostic differences by side and transverse colon tumors had K-modes mutation clustering that appeared more left than right sided. CMS profiles showed a decline in CMS1 and CMS3 and rise in CMS2 prevalence moving distally.Conclusions: Current right/left classifications may not fully recapitulate regional variations in tumor biology. Specifically, the sigmoid-rectal region appears unique and the transverse colon is distinct from other right-sided locations. Clin Cancer Res; 24(5); 1062-72. ©2017 AACRSee related commentary by Dienstmann, p. 989.

Colorectal cancer (CRC) incidence is increasing in adults younger than 50 years. This study evaluated clinical and molecular features to identify those features unique to early-onset CRC that differentiate these patients from patients 50 years old or older.Baseline characteristics were evaluated according to the CRC onset age with 3 independent cohorts. A fourth cohort was used to describe the impact of age on the consensus molecular subtype (CMS) prevalence.This retrospective review of more than 36,000 patients with CRC showed that early-onset patients were more likely to have microsatellite instability (P = .038), synchronous metastatic disease (P = .009), primary tumors in the distal colon or rectum (P < .0001), and fewer BRAF V600 mutations (P < .001) in comparison with patients 50 years old or older. Patients aged 18 to 29 years had fewer adenomatous polyposis coli (APC) mutations (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.35-0.90; P = .015) and an increased prevalence of signet ring histology (OR, 4.89; 95% CI, 3.23-7.39; P < .0001) in comparison with other patients younger than 50 years. In patients younger than 40 years, CMS1 was the most common subtype, whereas CMS3 and CMS4 were uncommon (P = .003). CMS2 was relatively stable across age groups. Early-onset patients with inflammatory bowel disease were more likely to have mucinous or signet ring histology (OR, 5.54; 95% CI, 2.24-13.74; P = .0004) and less likely to have APC mutations (OR, 0.24; 95% CI, 0.07-0.75; P = .019) in comparison with early-onset patients without predisposing conditions.Early-onset CRC is not only distinct from traditional CRC: special consideration should be given to and further investigations should be performed for both very young patients with CRC (18-29 years) and those with predisposing conditions. The etiology of the high rate of CMS1 in patients younger than 40 years deserves further exploration.

Colorectal tumors become more heterogeneous after progression on EGFR-inhibitors by developing multiple independent mutations. Upon discontinuation of treatment, the mutant allele burden declines over several months, which suggests that the changes may be dynamic. Monitoring genetic changes during treatment using ctDNA may provide opportunities to optimize therapeutic strategies.IntroductionKRAS andEGFR ectodomain-acquired mutations in patients with metastatic colorectal cancer (mCRC) have been correlated with acquired resistance to anti-EGFR monoclonal antibodies (mAbs). We investigated the frequency, co-occurrence, and distribution of acquiredKRAS andEGFR mutations in patients with mCRC refractory to anti-EGFR mAbs using circulating tumor DNA (ctDNA).Patients and methodsSixty-two post-treatment plasma and 20 matching pretreatment archival tissue samples fromKRASwt mCRC patients refractory to anti-EGFR mAbs were evaluated by high-sensitivity emulsion polymerase chain reaction forKRAS codon 12, 13, 61, and 146 andEGFR 492 mutations.ResultsPlasma analyses showed newly detectableEGFR andKRAS mutations in 5/62 [8%; 95% confidence interval (CI) 0.02–0.18] and 27/62 (44%; 95% CI 0.3–0.56) samples, respectively.KRAS codon 61 and 146 mutations were predominant (33% and 11%, respectively), and multipleEGFR and/orKRAS mutations were detected in 11/27 (41%) cases. The percentage of mutant allele reads was inversely correlated with time since last treatment with EGFR mAbs (P = 0.038). In the matching archival tissue, these mutations were detectable as low-allele-frequency clones in 35% of patients with plasma mutations after treatment with anti-EGFR mAbs and correlated with shorter progression-free survival (PFS) compared with the cases with no new mutations (3.0 versus 8.0 months,P = 0.0004).ConclusionNewly detectedKRAS and/orEGFR mutations in plasma ctDNA from patients refractory to anti-EGFR treatment appear to derive from rare, pre-existing clones in the primary tumors. These rare clones were associated with shorter PFS in patients receiving anti-EGFR treatment. Multiple simultaneous mutations inKRAS andEGFR in the ctDNA and the decline in allele frequency after discontinuation of anti-EGFR therapy in a subset of patients suggest that several resistance mechanisms can co-exist and that relative clonal burdens may change over time. Monitoring treatment-induced genetic alterations by sequencing ctDNA could identify biomarkers for treatment screening in anti-EGFR-refractory patients.

This selection from the NCCN Guidelines for Rectal Cancer focuses on management of malignant polyps and resectable nonmetastatic rectal cancer because important updates have been made to these guidelines. These recent updates include redrawing the algorithms for stage II and III disease to reflect new data supporting the increasingly prominent role of total neoadjuvant therapy, expanded recommendations for short-course radiation therapy techniques, and new recommendations for a "watch-and-wait" nonoperative management technique for patients with cancer that shows a complete response to neoadjuvant therapy. The complete version of the NCCN Guidelines for Rectal Cancer, available online at NCCN.org, covers additional topics including risk assessment, pathology and staging, management of metastatic disease, posttreatment surveillance, treatment of recurrent disease, and survivorship.

Abstract Purpose: This study aimed to detect cell-surface vimentin (CSV) on the surface of epithelial–mesenchymal transitioned (EMT) circulating tumor cells (CTC) from blood of patients with epithelial cancers. Experimental Design: In this study, 101 patients undergoing postsurgery adjuvant chemotherapy for metastatic colon cancer were recruited. EMT CTCs were detected from blood of patients using the 84-1 monoclonal antibody against CSV as a marker. EMT CTCs isolated were characterized further using EMT-specific markers, fluorescent in situ hybridization, and single-cell mutation analysis. Results: Using the 84-1 antibody, we detected CSV exclusively on EMT CTCs from a variety of tumor types but not in the surrounding normal cells in the blood. The antibody exhibited very high specificity and sensitivity toward different epithelial cancer cells. With this antibody, we detected and enumerated EMT CTCs from patients. From our observations, we defined a cutoff of &amp;lt;5 or ≥5 EMT CTCs as the optimal threshold with respect to therapeutic response using ROC curves. Using this defined threshold, the presence of ≥5 EMT CTCs was associated with progressive disease, whereas patients with &amp;lt;5 EMT CTCs showed therapeutic response. Conclusion: Taken together, the number of EMT CTCs detected correlated with the therapeutic outcome of the disease. These results establish CSV as a universal marker for EMT CTCs from a wide variety of tumor types and thus provide the foundation for emerging CTC detection technologies and for studying the molecular regulation of these EMT CTCs. Clin Cancer Res; 21(4); 899–906. ©2014 AACR.

Abstract In vitro, EGFR inhibition, combined with the BRAF inhibitor vemurafenib, causes synergistic cytotoxicity for BRAFV600E metastatic colorectal cancer, further augmented by irinotecan. The safety and efficacy of vemurafenib, irinotecan, and cetuximab in BRAF-mutated malignancies are not defined. In this 3+3 phase I study, patients with BRAFV600E-advanced solid cancers received cetuximab and irinotecan with escalating doses of vemurafenib. Nineteen patients (18 with metastatic colorectal cancer and 1 with appendiceal cancer) were enrolled. Three patients experienced dose-limiting toxicities. The MTD of vemurafenib was 960 mg twice daily. Six of 17 evaluable patients (35%) achieved a radiographic response by Response Evaluation Criteria in Solid Tumors 1.1 criteria, consistent with in vivo models demonstrating tumor regressions with the triplet regimen. Median progression-free survival was 7.7 months. BRAFV600E circulating cell-free DNA (cfDNA) trends correlated with radiographic changes, and acquired mutations from cfDNA in genes reactivating MAPK signaling were observed at progression. Significance: Vemurafenib, in combination with irinotecan and cetuximab, was well tolerated in patients with refractory, BRAF-mutated metastatic colorectal cancer, and both survival outcomes and response rates exceeded prior reports for vemurafenib and for irinotecan plus cetuximab in BRAFV600E metastatic colorectal cancer. In vivo models demonstrated regressions with the triplet, in contrast with vemurafenib and cetuximab alone. cfDNA predicted radiographic response and identified mutations reactivating the MAPK pathway upon progression. Cancer Discov; 6(12); 1352–65. ©2016 AACR. This article is highlighted in the In This Issue feature, p. 1293

Colorectal cancer (CRC) has been shown to acquire RAS and EGFR ectodomain mutations as mechanisms of resistance to epidermal growth factor receptor (EGFR) inhibition (anti-EGFR). After anti-EGFR withdrawal, RAS and EGFR mutant clones lack a growth advantage relative to other clones and decay; however, the kinetics of decay remain unclear. We sought to determine the kinetics of acquired RAS/EGFR mutations after discontinuation of anti-EGFR therapy.We present the post-progression circulating tumor DNA (ctDNA) profiles of 135 patients with RAS/BRAF wild-type metastatic CRC treated with anti-EGFR who acquired RAS and/or EGFR mutations during therapy. Our validation cohort consisted of an external dataset of 73 patients with a ctDNA profile suggestive of prior anti-EGFR exposure and serial sampling. A separate retrospective cohort of 80 patients was used to evaluate overall response rate and progression free survival during re-challenge therapies.Our analysis showed that RAS and EGFR relative mutant allele frequency decays exponentially (r2=0.93 for RAS; r2=0.94 for EGFR) with a cumulative half-life of 4.4 months. We validated our findings using an external dataset of 73 patients with a ctDNA profile suggestive of prior anti-EGFR exposure and serial sampling, confirming exponential decay with an estimated half-life of 4.3 months. A separate retrospective cohort of 80 patients showed that patients had a higher overall response rate during re-challenge therapies after increasing time intervals, as predicted by our model.These results provide scientific support for anti-EGFR re-challenge and guide the optimal timing of re-challenge initiation.

<h3>Importance</h3> Small-bowel adenocarcinomas (SBAs) are rare cancers with a significantly lower incidence, later stage at diagnosis, and worse overall survival than other intestinal-derived cancers. To date, comprehensive genomic analysis of SBA is lacking. <h3>Objective</h3> To perform in-depth genomic characterization of a large series of SBAs and other gastrointestinal tumors to draw comparisons and identify potentially clinically actionable alterations. <h3>Design, Setting, and Participants</h3> Prospective analysis was performed of clinical samples from patients with SBA (n = 317), colorectal cancer (n = 6353), and gastric carcinoma (n = 889) collected between August 24, 2012, and February 3, 2016, using hybrid-capture–based genomic profiling, at the request of the individual treating physicians in the course of clinical care for the purpose of making therapy decisions. <h3>Results</h3> Of the 7559 patients included in analysis, 4138 (54.7%) were male; the median age was 56 (range, 12-101) years. The frequency of genomic alterations seen in SBA demonstrated distinct differences in comparison with either colorectal cancer (<i>APC</i>: 26.8% [85 of 317] vs 75.9% [4823 of 6353],<i>P</i> &lt; .001; and<i>CDKN2A</i>: 14.5% [46 of 317] vs 2.6% [165 of 6353],<i>P</i> &lt; .001) or gastric carcinoma (<i>KRAS</i>: 53.6% [170 of 317] vs 14.2% [126 of 889],<i>P</i> &lt; .001;<i>APC</i>: 26.8% [85 of 317] vs 7.8% [69 of 889],<i>P</i> &lt; .001; and<i>SMAD4</i>: 17.4% [55 of 317] vs 5.2% [46 of 889],<i>P</i> &lt; .001).<i>BRAF</i>was mutated in 7.6% (484 of 6353) of colorectal cancer and 9.1% (29 of 317) of SBA samples, but V600E mutations were much less common in SBA, representing only 10.3% (3 of 29) of<i>BRAF</i>-mutated cases. The<i>ERBB2/HER2</i>point mutations (8.2% [26 of 317]), microsatellite instability (7.6% [13 of 170]), and high tumor mutational burden (9.5% [30 of 317]) were all enriched in SBA. Significant differences were noted in the molecular profile of unspecified SBA compared with duodenal adenocarcinoma, as well as in inflammatory bowel disease–associated SBAs. Targetable alterations in several additional genes, including<i>PIK3CA</i>and<i>MEK1</i>, and receptor tyrosine kinase fusions, were also identified in all 3 series. <h3>Conclusions and Relevance</h3> This study presents to our knowledge the first large-scale genomic comparison of SBA with colorectal cancer and gastric carcinoma. The distinct genomic differences establish SBA as a molecularly unique intestinal cancer. In addition, genomic profiling can identify potentially targetable genomic alterations in the majority of SBA cases (91%), and the higher incidence of microsatellite instability and tumor mutational burden in SBA suggests a potential role for immunotherapy.

Small bowel adenocarcinoma (SBA) is a rare malignancy of the gastrointestinal tract that has increased in incidence across recent years. Often diagnosed at an advanced stage, outcomes for SBA are worse on average than for other related malignancies, including colorectal cancer. Due to the rarity of this disease, few studies have been done to direct optimal treatment, although recent data have shown that SBA responds to treatment differently than colorectal cancer, necessitating a separate approach to treatment. The NCCN Guidelines for Small Bowel Adenocarcinoma were created to establish an evidence-based standard of care for patients with SBA. These guidelines provide recommendations on the workup of suspected SBA, primary treatment options, adjuvant treatment, surveillance, and systemic therapy for metastatic disease. Additionally, principles of imaging and endoscopy, pathologic review, surgery, radiation therapy, and survivorship are described.

Colorectal cancer (CRC) remains a leading cause of cancer-related deaths in the United States. Although immunotherapy has dramatically changed the landscape of treatment for many advanced cancers, the benefit in CRC has thus far been limited to patients with microsatellite instability high (MSI-H):DNA mismatch repair-deficient (dMMR) tumors. Recent studies in the refractory CRC setting have led to US Food and Drug Administration approvals for pembrolizumab as well as nivolumab (with or without ipilimumab) for tumors harboring an MSI-H:dMMR molecular profile. Several randomized controlled trials are underway to move immunotherapy into the frontline for metastatic cancer (with or without chemotherapy) and the adjuvant setting. Awareness of these studies is critical given the relatively low incidence (approximately 3%-5%) of MSI-H:dMMR in advanced or metastatic CRC to support study completion, because the results could be potentially practice changing. The real challenge in this disease is related to demonstrating the benefit of immunotherapy for the vast majority of patients with CRC not harboring MSI-H:dMMR. Given the rapid pace of scientific changes, this article provides a narrative review regarding the current landscape of immunotherapy for CRC. Particular attention is paid to the currently available data that inform today's clinical practice along with upcoming randomized controlled trials that may soon dramatically change the treatment landscape for CRC.

The National Cancer Institute Molecular Analysis for Therapy Choice (NCI-MATCH) trial, the largest national precision oncology study to date (> 1,100 sites) of patients with relapsed or refractory malignancies, assigned patients to targeted therapy in parallel phase II studies based on tumor molecular alterations. The anti-programmed death receptor 1 inhibitor nivolumab previously showed activity in mismatch repair (MMR)-deficient colon cancer. We hypothesized that nivolumab would have activity in patients with MMR-deficient, noncolorectal tumors.Eligible patients with relapsed or refractory tumors, good end-organ function, and Eastern Cooperative Oncology Group performance status of ≤ 1 underwent tumor biopsy for centralized screening of molecular alterations. MMR deficiency was defined by complete loss of nuclear expression of MLH1 or MSH2 MMR gene products by immunohistochemistry (IHC). Patients with MMR-deficient colorectal cancer were excluded. Nivolumab, 3 mg/kg every 2 weeks (28-day cycles) and 480 mg every 4 weeks after cycle 4, was administered intravenously. Disease reassessment was performed every 2 cycles. The primary end point was RECIST 1.1 objective response rate (ORR).Two percent of 4,902 screened patients had an MMR-deficient cancer by IHC. Forty-two evaluable patients were enrolled, with a median age of 60 years and a median of 3 prior therapies. The most common histologies were endometrioid endometrial adenocarcinoma (n = 13), prostate adenocarcinoma (n = 5), and uterine carcinosarcoma (n = 4). ORR was 36% (15 of 42 patients). An additional 21% of patients had stable disease. The estimated 6-, 12-, and 18-month progression-free survival rates were 51.3% (90% CI, 38.2% to 64.5%), 46.2% (90% CI, 33.1% to 59.3%), and 31.4% (90% CI, 18.7% to 44.2%), respectively. Median overall survival was 17.3 months. Toxicity was predominantly low grade.A variety of refractory cancers (2.0% of those screened) had MMR deficiency as defined in NCI-MATCH. Nivolumab has promising activity in MMR-deficient noncolorectal cancers of a wide variety of histopathologic types.

Fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) and gemcitabine plus nanoparticle albumin-bound (nab)-paclitaxel (GA) are first-line chemotherapy regimens for pancreatic cancer. Their relative efficacy in the setting of localized disease is unknown.To evaluate radiographic and serologic measures of responses associated with first-line chemotherapy with FOLFIRINOX or GA, and to determine the association between these drug regimens, putative measures of response, and survival.This case series assessed 485 consecutive patients who were diagnosed as having previously untreated localized pancreatic ductal adenocarcinoma at The University of Texas MD Anderson Cancer Center between January 1, 2010, and December 31, 2017, and who received at least 3 cycles of first-line chemotherapy with FOLFIRINOX or GA. The median (range) follow-up duration was 33 (2-28) months.Administration of FOLFIRINOX (285 patients [59%]) or GA (200 patients [41%]) as first-line chemotherapy.Resection rate, radiographic metrics (Response Evaluation Criteria in Solid Tumors [RECIST], version 1.1, and change in tumor volume or anatomic staging), a serologic metric (serum cancer antigen 19-9 level), and overall survival after administration of first-line chemotherapy.In total, 485 patients (266 [55%] male) were included in the analysis. Patients treated with FOLFIRINOX were generally younger (median [range] age at diagnosis: 61 [30-81] vs 71 [36-89] years; P = .001) and had better performance status as indicated by the Eastern Cooperative Oncology Group scale (range 0-4, with lower numbers representing better performance) score of 2 or lower (274 patients [96%] vs 165 patients [82%] P = .001) but more invasive tumors than patients who received GA (91 [32%] vs 90 [45%] resectable tumors; P = .01). After propensity score matching to control for these biases, many objective serologic and radiographic metrics of response associated with administration of FOLFIRINOX or GA-including low rates of local tumor downstaging-did not differ. However, RECIST partial response was more common among patients treated with FOLFIRINOX (27 of 140 patients [19%]) than with GA (8 of 140 patients [6%]; P = .001). Moreover, (chemo)radiation (50% vs 34%; P = .001) was more commonly administered to and pancreatectomy (27% vs 16%; P = .01) was subsequently performed more frequently for patients initially treated with FOLFIRINOX. The overall survival duration of patients treated with either regimen was similar (hazard ratio, 1.48; 95% CI, 0.97-2.26; P = .07).In this cohort of patients with localized pancreatic adenocarcinoma who received FOLFIRINOX or GA as their first line of therapy, FOLFIRINOX was associated with higher rates of RECIST partial response and subsequent pancreatectomy than GA, but the overall survival associated with these regimens was similar.

•In previously treated MSI-H/dMMR mCRC, nivolumab plus ipilimumab showed durable benefit with 4 years of follow-up.•ORR was 65%. The 48-month rates of progression-free survival and overall survival were 53% and 71%, respectively.•Significant and clinically meaningful improvements in quality of life were largely maintained with continuous treatment.•No new safety signals were identified, with a low rate (13% of patients) of any-grade TRAEs leading to discontinuation.•These results show the long-term benefit of nivolumab plus low-dose ipilimumab in previously treated MSI-H/dMMR mCRC. BackgroundIn the phase II multicohort CheckMate 142 study, nivolumab plus low-dose (1 mg/kg) ipilimumab provided robust and durable clinical benefit with a manageable safety profile in previously treated patients with microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC) at 13.4- and 25.4-month median follow-up (Overman MJ, Lonardi S, Wong KYM et al. Durable clinical benefit with nivolumab plus ipilimumab in DNA mismatch repair-deficient/microsatellite instability-high metastatic colorectal cancer. J Clin Oncol. 2018;36:773-779. Overman MJ, Lonardi S, Wong KYM, et al. Nivolumab plus low-dose ipilimumab in previously treated patients with microsatellite instability-high/mismatch repair deficient metastatic colorectal cancer: long-term follow-up. J Clin Oncol. 2019;37:635). Here, we present results from the 4-year follow-up of these patients.Patients and methodsPatients received nivolumab (3 mg/kg) plus low-dose (1 mg/kg) ipilimumab every 3 weeks (four doses) followed by nivolumab (3 mg/kg) every 2 weeks until disease progression. Primary endpoint was investigator-assessed objective response rate (ORR; as per RECIST version 1.1).ResultsA total of 119 patients were treated; 76% had ≥2 prior lines of therapy. Median follow-up was 50.9 months (range 46.9-62.7 months). Median duration of therapy was 24.9 months [95% confidence interval (CI) 15.8-33.2 months]. Investigator-assessed ORR increased from 55% (95% CI 45% to 64%) at 13.4 months to 65% (95% CI 55% to 73%) at 50.9 months with a disease control rate of 81% (95% CI 72% to 87%). The complete response rate increased from 3% at 13.4 months to 13% at 50.9 months. Partial responses were observed in 52% of patients; 21% had stable disease, and 12% had progressive disease. Median time to response was 2.8 months (range 1.1-37.1 months), and median duration of response was not reached (range 1.4+ to 58.0+ months). At data cut-off, 37 (48%) patients had ongoing responses. Median progression-free survival was not reached [95% CI 38.4 months-not estimable (NE)], and median overall survival was not reached (95% CI NE). Grade 3-4 treatment-related adverse events (TRAEs) were observed in 32% of patients; 13% of patients had any-grade TRAEs leading to discontinuation.ConclusionsThe results confirm long-term benefit of nivolumab plus low-dose ipilimumab for previously treated patients with MSI-H/dMMR mCRC. The safety profile was manageable with no new safety signals. In the phase II multicohort CheckMate 142 study, nivolumab plus low-dose (1 mg/kg) ipilimumab provided robust and durable clinical benefit with a manageable safety profile in previously treated patients with microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC) at 13.4- and 25.4-month median follow-up (Overman MJ, Lonardi S, Wong KYM et al. Durable clinical benefit with nivolumab plus ipilimumab in DNA mismatch repair-deficient/microsatellite instability-high metastatic colorectal cancer. J Clin Oncol. 2018;36:773-779. Overman MJ, Lonardi S, Wong KYM, et al. Nivolumab plus low-dose ipilimumab in previously treated patients with microsatellite instability-high/mismatch repair deficient metastatic colorectal cancer: long-term follow-up. J Clin Oncol. 2019;37:635). Here, we present results from the 4-year follow-up of these patients. Patients received nivolumab (3 mg/kg) plus low-dose (1 mg/kg) ipilimumab every 3 weeks (four doses) followed by nivolumab (3 mg/kg) every 2 weeks until disease progression. Primary endpoint was investigator-assessed objective response rate (ORR; as per RECIST version 1.1). A total of 119 patients were treated; 76% had ≥2 prior lines of therapy. Median follow-up was 50.9 months (range 46.9-62.7 months). Median duration of therapy was 24.9 months [95% confidence interval (CI) 15.8-33.2 months]. Investigator-assessed ORR increased from 55% (95% CI 45% to 64%) at 13.4 months to 65% (95% CI 55% to 73%) at 50.9 months with a disease control rate of 81% (95% CI 72% to 87%). The complete response rate increased from 3% at 13.4 months to 13% at 50.9 months. Partial responses were observed in 52% of patients; 21% had stable disease, and 12% had progressive disease. Median time to response was 2.8 months (range 1.1-37.1 months), and median duration of response was not reached (range 1.4+ to 58.0+ months). At data cut-off, 37 (48%) patients had ongoing responses. Median progression-free survival was not reached [95% CI 38.4 months-not estimable (NE)], and median overall survival was not reached (95% CI NE). Grade 3-4 treatment-related adverse events (TRAEs) were observed in 32% of patients; 13% of patients had any-grade TRAEs leading to discontinuation. The results confirm long-term benefit of nivolumab plus low-dose ipilimumab for previously treated patients with MSI-H/dMMR mCRC. The safety profile was manageable with no new safety signals.

Pembrolizumab significantly improves clinical outcomes in advanced/metastatic microsatellite instability high (MSI-H)/deficient mismatch repair (dMMR) solid tumors but is not well studied in the neoadjuvant space.This is a phase II open-label, single-center trial of localized unresectable or high-risk resectable MSI-H/dMMR tumors. Treatment is pembrolizumab 200 mg once every 3 weeks for 6 months followed by surgical resection with an option to continue therapy for 1 year followed by observation. To continue on study, patients are required to have radiographic or clinical benefit. The coprimary end points are safety and pathologic complete response. Key secondary end points are response rate and organ-sparing at one year for patients who declined surgery. Exploratory analyses include interrogation of the tumor immune microenvironment using imaging mass cytometry.A total of 35 patients were enrolled, including 27 patients with colorectal cancer and eight patients with noncolorectal cancer. Among 33 evaluable patients, best overall response rate was 82%. Among 17 (49%) patients who underwent surgery, the pathologic complete response rate was 65%. Ten patients elected to receive one year of pembrolizumab followed by surveillance without surgical resection (median follow-up of 23 weeks [range, 0-54 weeks]). An additional eight did not undergo surgical resection and received less than 1 year of pembrolizumab. During the study course of the trial and subsequent follow-up, progression events were seen in six patients (four of whom underwent salvage surgery). There were no new safety signals. Spatial immune profiling with imaging mass cytometry noted a significantly closer proximity between granulocytic cells and cytotoxic T cells in patients with progressive events compared with those without progression.Neoadjuvant pembrolizumab in dMMR/MSI-H cancers is safe and resulted in high rates of pathologic, radiographic, and endoscopic response, which has implications for organ-sparing strategies.

Despite unprecedented benefit from immune checkpoint inhibitors (ICIs) in patients with mismatch repair deficient (dMMR)/microsatellite instability high (MSI-H) advanced gastrointestinal cancers, a relevant proportion of patients shows primary resistance or short-term disease control. Since malignant effusions represent an immune-suppressed niche, we investigated whether peritoneal involvement with or without ascites is a poor prognostic factor in patients with dMMR/MSI-H metastatic colorectal cancer (mCRC) and gastric cancer (mGC) receiving ICIs.We conducted a global multicohort study at Tertiary Cancer Centers and collected clinic-pathological data from a cohort of patients with dMMR/MSI-H mCRC treated with anti-PD-(L)1 ±anti-CTLA-4 agents at 12 institutions (developing set). A cohort of patients with dMMR/MSI-high mGC treated with anti-PD-1 agents±chemotherapy at five institutions was used as validating dataset.The mCRC cohort included 502 patients. After a median follow-up of 31.2 months, patients without peritoneal metastases and those with peritoneal metastases and no ascites had similar outcomes (adjusted HR (aHR) 1.15, 95% CI 0.85 to 1.56 for progression-free survival (PFS); aHR 0.96, 95% CI 0.65 to 1.42 for overall survival (OS)), whereas inferior outcomes were observed in patients with peritoneal metastases and ascites (aHR 2.90, 95% CI 1.70 to 4.94; aHR 3.33, 95% CI 1.88 to 5.91) compared with patients without peritoneal involvement. The mGC cohort included 59 patients. After a median follow-up of 17.4 months, inferior PFS and OS were reported in patients with peritoneal metastases and ascites (aHR 3.83, 95% CI 1.68 to 8.72; aHR 3.44, 95% CI 1.39 to 8.53, respectively), but not in patients with only peritoneal metastases (aHR 1.87, 95% CI 0.64 to 5.46; aHR 2.15, 95% CI 0.64 to 7.27) when compared with patients without peritoneal involvement.Patients with dMMR/MSI-H gastrointestinal cancers with peritoneal metastases and ascites should be considered as a peculiar subgroup with highly unfavorable outcomes to current ICI-based therapies. Novel strategies to target the immune-suppressive niche in malignant effusions should be investigated, as well as next-generation ICIs or intraperitoneal approaches.

Context.— The US Food and Drug Administration (FDA) approved immune checkpoint inhibitor therapy for patients with advanced solid tumors that have DNA mismatch repair defects or high levels of microsatellite instability; however, the FDA provided no guidance on which specific clinical assays should be used to determine mismatch repair status. Objective.— To develop an evidence-based guideline to identify the optimal clinical laboratory test to identify defects in DNA mismatch repair in patients with solid tumor malignancies who are being considered for immune checkpoint inhibitor therapy. Design.— The College of American Pathologists convened an expert panel to perform a systematic review of the literature and develop recommendations. Using the National Academy of Medicine–endorsed Grading of Recommendations Assessment, Development and Evaluation approach, the recommendations were derived from available evidence, strength of that evidence, open comment feedback, and expert panel consensus. Mismatch repair immunohistochemistry, microsatellite instability derived from both polymerase chain reaction and next-generation sequencing, and tumor mutation burden derived from large panel next-generation sequencing were within scope. Results.— Six recommendations and 3 good practice statements were developed. More evidence and evidence of higher quality were identified for colorectal cancer and other cancers of the gastrointestinal (GI) tract than for cancers arising outside the GI tract. Conclusions.— An optimal assay depends on cancer type. For most cancer types outside of the GI tract and the endometrium, there was insufficient published evidence to recommend a specific clinical assay. Absent published evidence, immunohistochemistry is an acceptable approach readily available in most clinical laboratories.

12 Background: Encorafenib (E) and cetuximab (C) offers short-lived response and survival benefit for patients (pts) with MSS, BRAF V600E metastatic colorectal cancer (CRC). BRAF + EGFR inhibition induced a transient MSI-H phenotype in preclinical models of MSS, BRAF V600E CRC and may prime these tumors for response to immunotherapy with anti-PD-1 antibodies like nivolumab (N). Methods: In this single-arm, single-institution, phase I/II clinical trial, pts with treatment-refractory MSS, BRAF V600E metastatic CRC were eligible. No prior BRAF inhibitors, anti-EGFR antibody, or immunotherapy was permitted. Pts received E (300 mg PO daily), C (500 mg/m 2 IV q14 days), and N (480 mg IV q28 days). The primary endpoints were best overall response (RECIST 1.1) and safety/tolerability (CTCAE v5). A Simon two-stage design (H 0 : p≤.22; H a : p≥.45, where p= percentage of pts with radiographic response) was employed using a one-sided α=.05 and β=.20. In the first stage, ≥ 4/15 responses were needed in order for the trial to enroll 11 additional pts. Median progression-free survival (PFS) and overall survival (OS) were estimated via Kaplan-Meier. Results: All 26 pts have been enrolled - 23 patients treated, and 21 evaluable for response so far. Median age is 59 years (range, 32-85), and 14 (54%) are female. No dose-limiting toxicities occurred. Grade 3-4 treatment-related adverse events (AE) occurred in 4/22 (18%) patients. Grade 3 AEs included colitis, maculopapular rash, leukocytosis, and elevated amylase/lipase (all N=1). Grade 4 AEs in a single patient were myositis/myocarditis. Overall response rate is 45% (95% CI, 23-68), and disease control rate is 95% (95% CI, 75-100). Median PFS is 7.3 months (95% CI, 5.5-NA). Median OS is 11.4 months (95% CI, 7.6-NA). For the 9 pts thus far with responses, median duration of response is 8.1 months (95% CI, 7.3-NA). Updated results will be presented. Conclusions: E + C + N is effective and well-tolerated for pts with MSS, BRAF V600E metastatic CRC. The E+C+N regimen met its predefined efficacy endpoint and suggests a role for immunotherapy as a novel combination approach for this specific subpopulation of MSS metastatic CRC. A follow-up randomized phase II trial (SWOG 2107) to evaluate encorafenib/cetuximab with or without nivolumab in pts with MSS, BRAF V600E metastatic CRC will activate in early 2022. Clinical trial information: NCT04017650.

Over the past two decades of successive clinical trials in metastatic colorectal cancer (CRC), the median overall survival of both control and experimental arms has steadily improved. However, the incremental change in survival for metastatic CRC patients not treated on trial has not yet been quantified. We performed a retrospective review of 1420 patients with de novo metastatic CRC who received their primary treatment at the University of Texas M.D. Anderson Cancer Center (UTMDACC) from 2004 through 2019. Median OS was roughly stable for patients diagnosed between 2004 and 2012 (22.6 months) but since has steadily improved for those diagnosed in 2013 to 2015 (28.8 months), and 2016 to 2019 (32.4 months). Likewise, 5-year survival rate has increased from 15.7% for patients diagnosed from 2004 to 2006 to 26% for those diagnosed from 2013 to 2015. Notably, survival improved for patients with BRAFV600E mutant as well as microsatellite unstable (MSI-H) tumors. Multivariate regression analysis identified surgical resection of liver metastasis (HR = 0.26, 95% CI, 0.19-0.37), use of immunotherapy (HR = 0.44, 95% CI, 0.29-0.67) and use of third line chemotherapy (regorafenib or trifluridine/tipiracil, HR = 0.74, 95% CI, 0.58-0.95), but not year of diagnosis (HR = 0.99, 95% CI, 0.98-1), as associated with better survival, suggesting that increased use of these therapies are the drivers of the observed improvement in survival.

The College of American Pathologists (CAP) has developed a guideline on testing for mismatch repair (MMR) and microsatellite instability (MSI) for patients considered for immune checkpoint inhibitor therapy. ASCO has a policy and set of procedures for endorsing clinical practice guidelines that have been developed by other professional organizations.The CAP guideline was reviewed for developmental rigor by methodologists. An ASCO Endorsement Panel subsequently reviewed the content and the recommendations.The ASCO Endorsement Panel determined that the recommendations from the CAP guideline, published on August 3, 2022, are clear, thorough, and based on the most relevant scientific evidence. ASCO endorses Mismatch Repair and Microsatellite Instability Testing for Immune Checkpoint Inhibitor Therapy: Guideline From the College of American Pathologists in Collaboration With the Association for Molecular Pathology and Fight Colorectal Cancer.Within the guideline, MMR immunohistochemistry (IHC), MSI polymerase chain reaction, and MSI next-generation sequencing are all recommended testing options for colorectal cancer, MMR-IHC and MSI-polymerase chain reaction for gastroesophageal and small bowel cancer, and only MMR-IHC for endometrial cancer. No recommendation in favor of any testing method over another could be made for any other cancer. Tumor mutational burden was not recommended as a surrogate for DNA MMR deficiency. If MMR deficiency consistent with Lynch syndrome is detected, it should be communicated to the treating physician.Additional information is available at www.asco.org/molecular-testing-and-biomarkers-guidelines.

Abstract The relevance of KRAS mutation alleles to clinical outcome remains inconclusive in pancreatic adenocarcinoma (PDAC). We conducted a retrospective study of 803 patients with PDAC (42% with metastatic disease) at MD Anderson Cancer Center. Overall survival (OS) analysis demonstrated that KRAS mutation status and subtypes were prognostic ( p &lt; 0.001). Relative to patients with KRAS wildtype tumors (median OS 38 months), patients with KRAS G12R had a similar OS (median 34 months), while patients with KRAS Q61 and KRAS G12D mutated tumors had shorter OS (median 20 months [HR: 1.9, 95% CI 1.2–3.0, p = 0.006] and 22 months [HR: 1.7, 95% CI 1.3–2.3, p &lt; 0.001], respectively). There was enrichment of KRAS G12D mutation in metastatic tumors (34% vs 24%, OR: 1.7, 95% CI 1.2–2.4, p = 0.001) and enrichment of KRAS G12R in well and moderately differentiated tumors (14% vs 9%, OR: 1.7, 95% CI 1.05–2.99, p = 0.04). Similar findings were observed in the external validation cohort (PanCAN’s Know Your Tumor® dataset, n = 408).

β-Amyloid protein, which assembles into pathological aggregates deposited in Alzheimer's disease brain tissue, exhibits N-terminal heterogeneity both <i>in vitro</i> and <i>in vivo</i>. To investigate the effects of this N-terminal heterogeneity on the assembly characteristics and biophysical properties of β-amyloid, we synthesized a series of peptides with progressively shortened N termini (initial residues at positions β1, β4, β8, β12, and β17) and C termini extending to residue β40 or β42. We report that peptides with N-terminal deletions exhibit enhanced peptide aggregation relative to full-length species, as quantitatively assessed by sedimentation analyses. Overall, sedimentation levels were greater for peptides terminating at residue β42 than for those terminating at residue β40. To determine if established biophysical features of the full-length protein were maintained in the truncated peptides, structural and bioactive properties of these peptides were examined and compared. Full-length and truncated peptides exhibiting aggregation showed circular dichroism spectra consistent with predominant β-sheet conformation, fibrillar morphology under transmission electron microscopy, and significant toxicity in cultures of rat hippocampal neurons. These data demonstrate that N-terminal deletions enhance aggregation of β-amyloid into neurotoxic, β-sheet fibrils and suggest that such peptides may initiate and/or nucleate the pathological deposition of β-amyloid.

Adenocarcinomas of the small bowel and ampulla of Vater represent rare cancers that have limited data regarding first-line therapy. We conducted a phase II trial to evaluate the benefit of capecitabine in combination with oxaliplatin (CAPOX) in patients with advanced adenocarcinoma of small bowel or ampullary origin.Eligible patients with metastatic or unresectable tumors and no prior systemic chemotherapy for advanced disease participated in this phase II trial. CAPOX was administered as a 21-day cycle with oxaliplatin 130 mg/m(2) on day 1 and capecitabine 750 mg/m(2) twice a day on days 1 through 14. The primary end point was overall response rate as assessed by Response Evaluation Criteria in Solid Tumors.Thirty-one patients were enrolled onto the study, and 30 patients received study treatment. The confirmed overall response rate was 50%; three patients with metastatic disease achieved complete responses. The median time to progression (TTP) was 11.3 months, and the median overall survival (OS) was 20.4 months. Subset analysis of patients with metastatic disease only (n = 25) revealed a median TTP of 9.4 months and median OS of 15.5 months. The most common grades 3 or 4 toxicities included fatigue (30%), peripheral neuropathy (10%), vomiting (10%), diarrhea (10%), and neutropenia (10%).When administered to patients with good performance status, CAPOX is well tolerated and produces a superior response rate and longer OS compared with other regimens in the literature. CAPOX should be considered a new standard regimen for advanced small bowel and ampullary adenocarcinomas.

Purpose Oxaliplatin-based chemotherapy can cause hepatic sinusoidal injury, with resultant sinusoidal damage and portal hypertension. We sought to explore the relationship between oxaliplatin induced hepatic sinusoidal injury, increases in spleen size, and the subsequent development of thrombocytopenia. Patients and Methods We retrospectively assessed the relationship between chemotherapy exposure, changes in spleen size (determined by volumetric measurements), and platelet counts in 136 patients treated with adjuvant fluorouracil and oxaliplatin (FOLFOX) or fluoropyrimidine for stage II or III colorectal adenocarcinoma. Hepatic sinusoidal injury and changes in spleen size were graded in a separate population of 63 patients with metastatic colorectal cancer receiving fluoropyrimidine and oxaliplatin before liver resection. Results Spleen size increased in 86% of patients treated with adjuvant FOLFOX (P &lt; .001), with a ≥ 50% increase in 24% of patients. Spleen size did not significantly increase in patients treated with adjuvant fluoropyrimidine. Increases in spleen size correlated with cumulative oxaliplatin dose (P = .003). Patients with splenic enlargement ≥ 50% had higher rates of thrombocytopenia in the first year after completion of chemotherapy (27% v 5%; P = .003). In patients with hepatic metastases treated with preoperative fluoropyrimidine and oxaliplatin, increases in spleen size was a predictor of higher histologic grades of sinusoidal injury in both univariate (P = .03) and multivariate (P = .02) analyses. Conclusion Increases in spleen size correlate with increasing grade of hepatic sinusoidal injury and can serve as a simple method for identifying patients at risk for this toxicity. Oxaliplatin-induced increases in spleen size should be recognized as a potential etiology of persistent thrombocytopenia after oxaliplatin treatment.

Small bowel cancers account for 3% of all gastrointestinal malignancies and small bowel adenocarcinomas represent a third of all small bowel cancers. Rarity of small bowel adenocarcinomas restricts molecular understanding and presents unique diagnostic and therapeutic challenges. Better cross-sectional imaging techniques and development of enteroscopy and capsule endoscopy have facilitated earlier and more-accurate diagnosis. Surgical resection remains the mainstay of therapy for locoregional disease. In the metastatic setting, fluoropyrimidine and oxaliplatin-based chemotherapy has shown clinical benefit in prospective non-randomized trials. Although frequently grouped under the same therapeutic umbrella as large bowel adenocarcinomas, small bowel adenocarcinomas are distinct clinical and molecular entities. Recent progress in molecular characterization has aided our understanding of the pathogenesis of these tumours and holds potential for prospective development of novel targeted therapies. Multi-institutional collaborative efforts directed towards cogent understanding of tumour biology and designing sensible clinical trials are essential for developing improved therapeutic strategies. In this Review, we endeavour to outline an evidence-based approach to present-day management of small bowel adenocarcinoma, describe contemporary challenges and uncover evolving paradigms in the management of these rare 'orphan' neoplasias.

Adenocarcinomas of the appendix represent a heterogeneous disease depending on the presence of mucinous histology, histologic grade, and stage. In the current study, the authors sought to explore the interplay of these factors with systemic chemotherapy in a large population data set.Patients in the National Cancer Data Base (NCDB) who were diagnosed with mucinous, nonmucinous, and signet ring cell-type appendiceal neoplasms from 1985 through 2006 were selected. Multivariable Cox proportional hazards regression models were developed.A total of 11,871 patients met the inclusion criteria for the current study: 50.3% had mucinous neoplasms, 40.5% had nonmucinous neoplasms, and 9.2% had signet ring cell-type neoplasms. The 5-year overall survival (OS) stratified by grade was similar among patients with American Joint Committee on Cancer stage I to stage III disease but not for those with stage IV disease. The median OS for patients with stage IV mucinous and nonmucinous tumors was 6.4 years and 2.3 years, respectively, for those with well differentiated histology (P<.0001) and was 1.5 years and 0.8 years, respectively, for those with poorly differentiated histology (P<.0001). In multivariable modeling for stage I to III disease, adjuvant chemotherapy improved OS for both mucinous and nonmucinous histologies, with hazard ratios (HRs) of 0.78 (95% confidence interval [95% CI], 0.68-0.89 [P = .0002]) and 0.83 (95% CI, 0.74-0.94 [P = .002]), respectively. For patients with stage IV disease, systemic chemotherapy significantly improved OS for those with nonmucinous (HR, 0.72; 95% CI, 0.64-0.82 [P<.0001]) but not mucinous (HR, 0.95; 95% CI, 0.86-1.04 [P = .2) histologies, although this was grade-dependent. The median OS for chemotherapy versus no chemotherapy was 6.4 years versus 6.5 years (P value not significant) for patients with mucinous, well-differentiated tumors and 1.6 years versus 1.0 years (P = .0007) for patients with mucinous, poorly differentiated tumors.Adjuvant chemotherapy demonstrated a significant OS benefit regardless of histology. However, for patients with stage IV disease, the benefit of systemic chemotherapy varied by tumor histology and grade, with patients with well-differentiated, mucinous, appendiceal adenocarcinomas deriving no survival benefit from systemic chemotherapy. Cancer 2016;122:213-221. © 2015 American Cancer Society.

High circulating neutrophil-lymphocyte ratio (NLR) appears to be prognostic in metastatic colorectal cancer (mCRC). We investigated the relationship of NLR with circulating cytokines and molecular alterations. We performed retrospective analyses on multiple cohorts of CRC patients (metastatic untreated (n=166), refractory metastatic (n=161), hepatectomy (n=198), stage 2/3 (n=274), and molecularly screened (n=342)). High NLR (ratio of absolute neutrophil-to-lymphocyte counts in peripheral blood) was defined as NLR>5. Plasma cytokines were evaluated using multiplex-bead assays. Kaplan–Meier estimates, non-parametric correlation analysis, and hierarchical cluster analyses were used. High NLR was associated with poor prognosis in mCRC (hazard ratio (HR) 1.73; 95% confidence interval (CI):1.03–2.89; P=0.039) independent of known prognostic factors and molecular alterations (KRAS/NRAS/BRAF/PIK3CA/CIMP). High NLR correlated with increased expression of interleukin 6 (IL-6), IL-8, IL-2Rα, hepatocyte growth factor, macrophage-colony stimulating factor, and vascular epidermal growth factor in exploratory (n=39) and validation (n=166) cohorts. Fourteen additional cytokines correlated with high NLR in the validation cohort. All 20 cytokines fell into three major clusters: inflammatory cytokines, angiogenic cytokines, and epidermal growth factor ligands. In mCRC, composite stratification based on NLR-cytokine score provided enhanced prognostic information (HR 2.09; 95% CI: 1.59–2.76; P<0.001) over and above NLR. High NLR is an independent poor prognostic marker in CRC and correlates with a distinct cytokine profile related to key biological processes involved in carcinogenesis. A composite NLR-cytokine stratification has enhanced prognostic value in mCRC.

Because of its rarity, adenocarcinoma of the small intestine is frequently compared to adenocarcinoma of the colon, although the validity of this comparison is not known. Patients with small and large bowel adenocarcinoma (SBA and LBA) diagnosed between 1988 and 2007 were identified from the Surveillance, Epidemiology, and End Results registry. Age-standardized incidence and mortality rates were determined. Cancer-specific survival (CSS) stratified by stage and by number of assessed lymph nodes was calculated. A total of 4518 and 261,521 patients with SBA and LBA, respectively, were identified. In comparison to LBA, patients with SBA were younger and presented with disease of higher stage and histologic grade. The age-standardized incidence rates decreased for LBA (−1.24% per year) but increased for SBA (+1.47% per year). Although age-standardized mortality rates decreased for both LBA and SBA, the decreases were more pronounced for LBA. Five-year CSS was worse for resected SBA compared with resected LBA, although this difference diminished when comparing cases having eight or more lymph nodes assessed. The relative reduction in CSS when selecting eight or more lymph nodes was much greater for duodenal as opposed to jejunal/ileal subsite of the small bowel. With nodal selection the absolute difference in CSS between LBA and SBA for stages I, II, and III was 13, 15.9, and 18.5%, respectively. Adequate nodal assessment is much less common in SBA than LBA; and it appears that SBA, in particular duodenal adenocarcinoma, is understaged. Even after corrections to minimize the effect of stage migration and inadequate lymph node evaluation, SBA demonstrated distinctly worse CSS than LBA.

The purpose of this study was to evaluate a single-institution experience with delivery of preoperative therapy to patients with pancreatic ductal adenocarcinoma (PDAC) prior to pancreatoduodenectomy (PD). Consecutive patients (622) with PDAC who underwent PD following chemotherapy and/or chemoradiation between 1990 and 2014 were retrospectively reviewed. Preoperative treatment regimens, clinicopathologic characteristics, operative details, and long-term outcomes in four successive time periods (1990–1999, 2000–2004, 2005–2009, 2010–2014) were evaluated and compared. The average number of patients per year who underwent PD following preoperative therapy as well as the proportion of operations performed for borderline resectable and locally advanced (BR/LA) tumors increased over time. The use of induction systemic chemotherapy, as well as postoperative adjuvant chemotherapy, also increased over time. Throughout the study period, the mean EBL decreased while R0 margin rates and vascular resection rates increased overall. Despite the increase in BR/LA resections, locoregional recurrence (LR) rates remained similar over time, and overall survival (OS) improved significantly (median 24.1, 28.1, 37.3, 43.4 months, respectively, p < 0.0001). Despite increases in case complexity, relatively low rates of LR have been maintained while significant improvements in OS have been observed. Further improvements in patient outcomes will likely require disruptive advances in systemic therapy.

BRAF mutations occur in 5% to 10% of metastatic colorectal cancers and are biomarkers associated with a poor prognosis. However, the outcomes with standard chemotherapy over sequential lines of therapy in a large cohort of patients with BRAF-mutant tumors have not been described.We searched the M.D. Anderson Cancer Center databases for patients with colorectal cancer and identified BRAF mutations between December 2003 and May 2012. Patients were analyzed for clinical characteristics, PFS, overall survival, and chemotherapeutic agents used. Survival was estimated according to the Kaplan-Meier method.Among the 1567 patients tested for BRAF mutations at our institution, 127 (8.1%) had tumors with BRAF mutations. The 71 patients who presented with metastatic disease received a median of 2 lines of chemotherapy. For the first 3 lines of chemotherapy, median PFS was 6.3 months (n = 69 patients; 95% confidence interval [CI], 4.9-7.7 months), 2.5 months (n = 58 patients; 95% CI, 1.8-3.0 months), and 2.6 months (n = 31 patients; 95% CI, 1.0-4.2 months), respectively. Median PFS was not affected by the backbone chemotherapeutic agent in the first-line setting, whether oxaliplatin-based or irinotecan-based (6.4 months vs. 5.4 months, respectively; P = .99).PFS is expectedly poor for patients with BRAF-mutated metastatic colorectal cancer. Despite the ascertainment bias present (with testing preferentially performed in patients suitable for clinical trials in refractory disease), these data provide historic controls suitable for future study design and support the idea that novel therapeutic options are essential in this population.

The ampulla of Vater is a complex cellular environment from which adenocarcinomas arise to form a group of histopathologically heterogenous tumors. To evaluate the molecular features of these tumors, 98 ampullary adenocarcinomas were evaluated and compared to 44 distal bile duct and 18 duodenal adenocarcinomas. Genomic analyses revealed mutations in the WNT signaling pathway among half of the patients and in all three adenocarcinomas irrespective of their origin and histological morphology. These tumors were characterized by a high frequency of inactivating mutations of ELF3, a high rate of microsatellite instability, and common focal deletions and amplifications, suggesting common attributes in the molecular pathogenesis are at play in these tumors. The high frequency of WNT pathway activating mutation, coupled with small-molecule inhibitors of β-catenin in clinical trials, suggests future treatment decisions for these patients may be guided by genomic analysis.

Circulating angiogenic factors are altered in patients with mCRC receiving bevacizumab. Evaluation of alterations in levels of VEGF ligands may provide insights into possible resistance mechanisms.PlGF, VEGF-A, VEGF-C, and VEGF-D were measured from two cohorts of patients. Sequential plasma samples were obtained from a discovery cohort of 42 patients treated with chemotherapy and bevacizumab. A validation cohort included plasma samples from a cross-sectional of 403 patients prior to chemotherapy, or after progression on a regimen with or without bevacizumab.In the discovery cohort, VEGF-C was increased prior to progression and at progression (+49% and +95%, respectively, p<0.01), consistent with previously reported elevations in PlGF. Levels of VEGF-D were increased (+23%) at progression (p=0.05). In the validation cohort, samples obtained from patients after progression on a regimen with bevacizumab had higher levels of PlGF and VEGF-D (+43% and +6%, p=0.02, p=0.01, respectively) compared to untreated patients, but failed to validate the increase in VEGF-C seen in the first cohort. Patients who progressed on chemotherapy with bevacizumab had significantly elevated levels of PlGF (+88%) but not VEGF-C and VEGF-D compared to patients treated with chemotherapy alone. Elevations of PlGF and VEGF-D appeared transient and returned to baseline with a half-life of 6 weeks.Increases in PlGF and VEGF-D were observed after progression on chemotherapy with bevacizumab. These changes appear to be reversible after discontinuing therapy. These ligands are associated with resistance to bevacizumab-containing chemotherapy in mCRC, but causation remains to be established.

3501 Background: Evidence supports use of nivolumab (N) in MSI-H mCRC. N, a fully human anti-PD-1 mAb and ipilimumab (I), a humanized anti-CTLA-4 mAb, have favorable safety & efficacy in other tumors. CheckMate-142, a phase 2 study, evaluates N ± I in pts with mCRC, MSI-H and non-MSI-H. Methods: Pts had ECOG PS 0–1, and intolerance/progression on ≥ 1 tx. MSI-H pts received N 3 mg/kg q2 wk (N3) or N 3 mg/kg + I 1 mg/kg q3 wk (N3+I1) x 4 doses followed by N3 until disease progression (PD) or other discontinuation. Initial evaluation of N+I at 3 doses was completed in non-MSI-H pts. Primary endpoint was investigator-reported ORR by RECIST 1.1; other endpoints were safety, OS, and PFS. Results: 33 (N3) and 26 (N3+I1) MSI-H pts, and 3 (N1+I1), 10 (N1+I3), and 10 (N3+I1) non-MSI-H pts were enrolled. 82% (N3) and 92% (N3+I1) of MSI-H and 100% of non-MSI-H pts had ≥ 2 prior regimens. 15% (N3) and 25% (N3+I1) of MSI-H pts had known BRAF V600E. 17 (52%; N3) and 19 (73%; N3+I1) MSI-H pts remain on tx. Efficacy results are shown in the Table. In MSI-H pts, tx-related adverse events (TRAEs) occurred in 26 (79%; N3) and 22 pts (85%; N3+I1); most common were diarrhea and fatigue (27% each; N3) and diarrhea (46%; N3+I1). Grade 3–4 TRAEs occurred in 7 (N3) and 8 pts (N3+I1). One pt on N3 had a Grade 5 TRAE (sudden death). In non-MSI-H pts median (95% CI) PFS was 1.4 mo (1.2–1.9; pooled N+I). Conclusions: N and N+I were well tolerated in most pts and demonstrated encouraging clinical activity and survival in MSI-H mCRC. This study is ongoing. Clinical trial information: NCT02060188.MSI-Ha efficacy. N3 (n = 33) N3+I1 (n = 26) ORR, n (%) 9 (27) 4 (15) CR 0 0 Confirmed PR 9 (27) 4 (15) SD 8 (24) 17 (65) PD 11 (33) 3 (12) Not determined/not reported 5 (15) 2 (8) Median duration of response (95% CI), mo NR (4.2–NE) NR (NE–NE) Median PFS (95% CI), mo 5.3 (1.4–NE) NR (NE–NE) 4-mo PFS rate,b % 55 80 Median OS (95% CI), mo 16.3 (8.3–NE) NR (NE–NE) 5-mo OS rate,c % 75 100 NR, not reached; NE, not estimable aBy local screen bPFS Kaplan-Meier plot estimate, N3 = 17/33 events, N3+I1 = 4/26 events cPFS Kaplan-Meier plot estimate, N3 = 11/33 events, N3+I1 = 0/26 events

A Japan Society of Clinical Oncology (JSCO)-hosted expert meeting was held in Japan on 27 October 2019, which comprised experts from the JSCO, the Japanese Society of Medical Oncology (JSMO), the European Society for Medical Oncology (ESMO), the American Society of Clinical Oncology (ASCO), and the Taiwan Oncology Society (TOS). The purpose of the meeting was to focus on what we have learnt from both microsatellite instability (MSI)/deficient mismatch repair (dMMR) biomarkers in predicting the efficacy of anti-programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) immunotherapy, and the neurotrophic tyrosine receptor kinase (NTRK) gene fusions in predicting the efficacy of inhibitors of the tropomyosin receptor kinase (TRK) proteins across a range of solid tumour types. The recent regulatory approvals of the anti-PD-1 antibody pembrolizumab and the TRK inhibitors larotrectinib and entrectinib, based on specific tumour biomarkers rather than specific tumour type, have heralded a paradigm shift in cancer treatment approaches. The purpose of the meeting was to develop international expert consensus recommendations on the use of such tumour-agnostic treatments in patients with solid tumours. The aim was to generate a reference document for clinical practice, for pharmaceutical companies in the design of clinical trials, for ethics committees in the approval of clinical trial protocols and for regulatory authorities in relation to drug approvals, with a particular emphasis on diagnostic testing and patient selection.

BackgroundPoorly differentiated and signet ring cell adenocarcinomas of the appendix represent a subset with aggressive tumor biology and poor outcomes with few studies evaluating the impact of systemic chemotherapy and cytoreductive surgery (CRS).Patients and methodsA retrospective chart review of patients with either poorly differentiated and signet ring cell appendiceal adenocarcinomas was completed from 1992 to 2010.ResultsOne hundred forty-two patients were identified. Seventy-eight patients with metastatic disease received chemotherapy. Radiographic response was 44%, median progression-free survival (PFS) was 6.9 months, and median overall survival (OS) was 1.7 years. In multivariate analysis, response to chemotherapy [hazard ratio (HR) 0.5; P = 0.02] predicted improved PFS, and complete CRS (HR 0.3; P = 0.004) predicted improved OS. Patients who underwent complete CRS (n = 26) had a median relapse-free survival (RFS) of 1.2 years and a median OS of 4.2 years. In multivariate analysis for this subset, complete cytoreduction score of 0 was significantly correlated with improved RFS (HR 0.07; P = 0.01) and OS (HR 0.02; P = 0.01).ConclusionsSystemic chemotherapy appears to be a viable treatment option for patients with metastatic poorly differentiated and signet ring cell appendiceal adenocarcinomas. Complete CRS is associated with improved RFS and OS, though part of this benefit likely reflects the selection of good tumor biology.

With the recent U.S. Food and Drug Administration approvals of pembrolizumab and nivolumab for refractory deficient mismatch repair metastatic colorectal cancer, immune checkpoint inhibitors have now entered into clinical care for gastrointestinal cancers. Extensive ongoing efforts are exploring additional combinations of therapy in both deficient and proficient mismatch repair colorectal cancer. This review will outline the current status of such efforts and discuss the critical aspects of recognition and management of immune-related toxicities from checkpoint inhibitors.

Though histological grade is known to have a major prognostic impact in metastatic mucinous appendiceal adenocarcinomas, the prognostic impact of grade in localized disease, and the validity of the American Joint Committee on Cancer AJCC Staging Manual 7th edition's decision to combine moderately and poorly differentiated mucinous adenocarcinomas into a single mucinous high-grade category, is not known.Patients with adenocarcinoma of the appendix diagnosed between 1988 and 2007 were identified from the SEER database. Cancer-specific survival (CSS) stratified by histological subtype, stage, and grade was calculated, and Cox proportional hazards regression analyses were performed.We analyzed a total of 2469 appendiceal adenocarcinomas, of which 1375 had mucinous histology and 860 had nonmucinous histology. Though overall CSS was similar for mucinous and nonmucinous subtypes, differences in stage distribution and stage-stratified CSS were seen. Female sex, stage IV disease, and well-differentiated histology were more common for mucinous adenocarcinomas. Histological grade had a strong prognostic impact, especially in patients with stage IV mucinous adenocarcinoma. The adjusted hazard ratios for stage IV moderately and poorly differentiated histological grade were 1.63 [95% confidence interval (CI): 1.14-2.34] and 4.94 (95% CI: 3.32-7.35) for mucinous histology, in comparison with 1.44 (95% CI: 0.82-2.52) and 1.90 (95% CI: 0.95-3.80) for nonmucinous histology, respectively.The strong prognostic impact of histological grade for mucinous adenocarcinomas is primarily restricted to stage IV disease. Stage IV moderately and poorly differentiated mucinous adenocarcinomas have distinctly different CSS and these data do not support the combination of these 2 histological grades in the recent AJCC Staging Manual 7th edition.

We previously demonstrated that a major pathologic response to preoperative therapy, defined histopathologically by the presence of less than 5% viable cancer cells in the surgical specimen, is an important prognostic factor for patients with pancreatic ductal adenocarcinoma. However, to our knowledge, the patients most likely to experience a significant response to therapy are undefined.To identify clinical factors associated with major pathologic response in a large cohort of patients who underwent preoperative therapy and pancreatectomy for pancreatic ductal adenocarcinoma.Retrospective review of a prospectively maintained database at University of Texas MD Anderson Cancer Center. The study included 583 patients with histopathologically confirmed pancreatic ductal adenocarcinoma who received preoperative therapy prior to pancreatectomy between 1990 and 2015.Preoperative therapy consisted of systemic chemotherapy alone (n = 38; 6.5%), chemoradiation alone (n = 261; 44.8%), or both (n = 284; 48.7%) prior to pancreatoduodenectomy (n = 514; 88.2%), distal pancreatectomy (n = 62; 10.6%), or total pancreatectomy (n = 7; 1.2%).Clinical variables associated with a major pathologic response (pathologic complete response or <5% residual cancer cells) were evaluated using logistic regression.Among all patients, the mean (SD) age was 63.7 (9.2) years, and 53.0% were men. A major pathologic response was seen in 77 patients (13.2%) including 23 (3.9%) who had a complete pathologic response. The median overall survival duration was significantly longer for patients who had a major response than for those who did not (73.4 months vs 32.2 months, P < .001). On multivariate logistic regression, only age younger than 50 years, baseline serum cancer antigen 19-9 level less than 200 U/mL, and gemcitabine as a radiosensitizer were associated with a major response. The number of these positive factors was associated with the likelihood of a major response in a stepwise fashion (0, 7.5%; 1, 12.7%; 2, 16.9%; 3, 35.7%; P = .009).Although a major pathologic response occurs infrequently following preoperative therapy for pancreatic ductal adenocarcinoma, it is associated with a significantly improved prognosis. Of the patient- and treatment-related factors we analyzed, only young age, low baseline cancer antigen 19-9, and gemcitabine as a radiosensitizer were associated with a major pathologic response. Given its association with long-term survival, better predictors of response and more effective preoperative regimens should be aggressively sought.

Cell-free (cf) DNA in the plasma of cancer patients offers an easily obtainable source of biologic material for mutation analysis. Plasma samples from 157 patients with advanced cancers who progressed on systemic therapy were tested for 21 mutations in BRAF, EGFR, KRAS, and PIK3CA using the BEAMing method and results were compared to mutation analysis of archival tumor tissue from a CLIA-certified laboratory obtained as standard of care from diagnostic or therapeutic procedures. Results were concordant for archival tissue and plasma cfDNA in 91% cases for BRAF mutations (kappa = 0.75, 95% confidence interval [CI] 0.63 - 0.88), in 99% cases for EGFR mutations (kappa = 0.90, 95% CI 0.71- 1.00), in 83% cases for KRAS mutations (kappa = 0.67, 95% CI 0.54 - 0.80) and in 91% cases for PIK3CA mutations (kappa = 0.65, 95% CI 0.46 - 0.85). Patients (n = 41) with > 1% of KRAS mutant cfDNA had a shorter median survival compared to 20 patients with </= 1% of KRAS mutant DNA (4.8 vs. 7.3 months, p=0.008). Similarly, 67 patients with >1% of mutant cfDNA (BRAF, EGFR, KRAS, or PIK3CA) had a shorter median survival compared to 33 patients with </= 1% of mutant cfDNA (5.5 vs. 9.8 months, p = 0.001), which was confirmed in multivariable analysis. [Corrected]

Early detection and management of treatment-related adverse events (TRAEs) in patients receiving immune checkpoint inhibitors may improve outcomes. In CheckMate 142, nivolumab (3 mg/kg) plus low-dose ipilimumab (1 mg/kg) provided durable clinical benefit (objective response rate [ORR] 55%, median duration of response not reached, 12-month overall survival [OS] rate 85%) and manageable safety for previously treated microsatellite instability-high and/or mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC). In-depth safety and additional efficacy outcomes from CheckMate 142 are presented.Safety assessments included frequency of TRAEs, select TRAEs (sTRAEs), and immune-mediated adverse event incidences; time to onset (TTO); time to resolution (TTR); immune-modulating medication (IMM) use; dose delay; and sTRAE occurrence after resuming therapy. Efficacy assessments included ORR and survival analyses in patients with sTRAEs with or without concomitant IMM treatment and patients without sTRAEs.Among 119 patients, 25%, 23%, 19%, 5%, 5%, and 29% experienced an endocrine, gastrointestinal, hepatic, pulmonary, renal, or skin sTRAE, respectively; the majority (57%) were grade 1/2. sTRAEs occurred early (median TTO, 5.2-12.6 weeks). Nonendocrine sTRAEs resolved in most (>71%) patients (median TTR, 1.5-9.0 weeks). IMMs were used to manage sTRAEs in 22%-56% of patients (most resolved). Of patients with dose delay because of sTRAEs, 25 of 29 resumed treatment. Patients with or without sTRAEs had comparable ORR (57% vs. 52%) and 12-month OS rates (93% vs. 75%). Similar results were observed in patients with or without sTRAEs regardless of IMM use (ORR 52% vs. 57%; OS rates 87% vs. 82%).The benefit-risk profile of nivolumab plus low-dose ipilimumab provides a promising treatment option for patients with previously treated MSI-H/dMMR mCRC.Nivolumab (NIVO) plus low-dose (1 mg/kg) ipilimumab (IPI) received U.S. Food and Drug Administration approval for patients with microsatellite instability-high and/or mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC) that progressed following treatment with a fluoropyrimidine, oxaliplatin, and irinotecan based on results from CheckMate 142. In this safety analysis, the majority of select treatment-related adverse events (sTRAEs) occurred early, were managed using evidence-based treatment algorithms, and resolved. Efficacy outcomes were comparable between patients with or without sTRAEs regardless of the use of concomitant immune-modulating medications. The benefit-risk profile of NIVO + low-dose IPI provides a promising treatment option for MSI-H/dMMR mCRC.

High EREG and AREG expression, and left-sided primary tumours are associated with superior efficacy of anti-epidermal growth factor receptor (EGFR) therapy in metastatic colorectal cancer (CRC), but a unifying explanation of these findings is lacking.RNA-seq, gene expression arrays, and DNA methylation profiling were completed on 179 CRC tumours. Results were validated using independent The Cancer Genome Atlas data sets. An independent cohort of 198 KRAS wild-type metastatic CRC tumours was tested for CpG island methylator phenotype (CIMP) status, and progression-free survival (PFS) with the first anti-EGFR regimen was retrospectively determined.EREG and AREG expression was highly inversely correlated with methylation and was inversely associated with right-sided primary tumour, BRAF mutation, and CIMP-high status. Treatment of CRC cell lines with hypomethylating agents decreased methylation and increased expression of EREG. Inferior PFS with anti-EGFR therapy was associated with CIMP-high status, BRAF mutation, NRAS mutation, and right-sided primary tumour on univariate analysis. Among known BRAF/NRAS wild-type tumours, inferior PFS remained associated with CIMP-high status (median PFS 5.6 vs 9.0 mo, P=0.023).EREG and AREG are strongly regulated by methylation, and their expression is associated with CIMP status and primary tumour site, which may explain the association of primary tumour site and EREG/AREG expression with anti-EGFR therapy efficacy.

Abstract Cell-free (cf) DNA from plasma offers an easily obtainable material for BRAF mutation analysis for diagnostics and response monitoring. In this study, plasma-derived cfDNA samples from patients with progressing advanced cancers or malignant histiocytosis with known BRAFV600 status from formalin-fixed paraffin-embedded (FFPE) tumors were tested using a prototype version of the Idylla BRAF Mutation Test, a fully integrated real-time PCR-based test with turnaround time about 90 minutes. Of 160 patients, BRAFV600 mutations were detected in 62 (39%) archival FFPE tumor samples and 47 (29%) plasma cfDNA samples. The two methods had overall agreement in 141 patients [88%; κ, 0.74; SE, 0.06; 95% confidence interval (CI), 0.63–0.85]. Idylla had a sensitivity of 73% (95% CI, 0.60–0.83) and specificity of 98% (95% CI, 0.93–1.00). A higher percentage, but not concentration, of BRAFV600 cfDNA in the wild-type background (&amp;gt;2% vs. ≤ 2%) was associated with shorter overall survival (OS; P = 0.005) and in patients with BRAF mutations in the tissue, who were receiving BRAF/MEK inhibitors, shorter time to treatment failure (TTF; P = 0.001). Longitudinal monitoring demonstrated that decreasing levels of BRAFV600 cfDNA were associated with longer TTF (P = 0.045). In conclusion, testing for BRAFV600 mutations in plasma cfDNA using the Idylla BRAF Mutation Test has acceptable concordance with standard testing of tumor tissue. A higher percentage of mutant BRAFV600 in cfDNA corresponded with shorter OS and in patients receiving BRAF/MEK inhibitors also with shorter TTF. Mol Cancer Ther; 15(6); 1397–404. ©2016 AACR.

HER2 amplification has been implicated in resistance to therapy with anti-epidermal growth factor receptor antibodies (anti-EGFRabs) in metastatic colorectal cancer (mCRC). The purpose of the study was to validate the predictive impact of HER2 amplification in mCRC.We analyzed patients with RAS/BRAF wild-type mCRC across two distinct cohorts. In cohort 1 (n = 98), HER2 amplification was tested in tumor tissue using dual in situ hybridization (HER2 amplification: HER2/CEP17 ratio, 2.0 or greater). Cohort 2 (n = 70) included 16 patients with HER2 amplification and 54 HER2 nonamplified controls identified by next-generation sequencing (HER2 amplification: four or more copies) who had received prior anti-EGFRabs. The primary end point was progression-free survival (PFS) on treatment with anti-EGFRab therapy, which was estimated and compared using the Kaplan-Meier method and log-rank test.Median PFS in cohort 1 on anti-EGFRab-based therapy was significantly shorter in patients with HER2 amplification compared with HER2 nonamplified patients (2.8 v 8.1 months, respectively; hazard ratio [HR], 7.05; 95% CI, 3.4 to 14.9; P < .001). These findings were validated in cohort 2 (median PFS for HER2 amplified v nonamplified: 2.8 v 9.3 months, respectively; HR, 10.66; 95% CI, 4.5 to 25.1; P < .001). The median PFS on therapy without anti-EGFRabs was similar among HER2-amplified and nonamplified patients in both cohort 1 (9.7 v 11.1 months, respectively; HR, 1.01; 95% CI, 0.4 to 2.4; P = .97) and cohort 2 (9.6 v 11.3 months, respectively; HR, 1.21; 95% CI, 0.5 to 3.1; P = .66). In multivariable analyses, HER2 amplification emerged as a single independent predictor of poor PFS on anti-EGFRab therapy in both cohort 1 (HR, 6.48; 95% CI, 3.1 to 13.6; P < .001) and cohort 2 (HR, 10.1; 95% CI, 4.3 to 23.9; P < .001).HER2 amplification in RAS/RAF wild-type mCRC seems to be a predictive biomarker for lack of efficacy of anti-EGFRab therapy. Screening patients with RAS/BRAF wild-type mCRC for HER2 amplification should be considered before anti-EGFRab treatment to guide therapy and to identify patients for early referral to clinical trials.

Purpose: Liquid biopsies allow the tracking of clonal dynamics and detection of mutations during treatment.Experimental Design: We evaluated under blinded conditions the ability of cell-free DNA (cfDNA) to detect RAS/BRAF mutations in the plasma of 42 metastatic colorectal cancer patients treated on a phase Ib/II trial of FOLFOX and dasatinib, with or without cetuximab.Results: Prior to treatment, sequencing of archival tissue detected mutations in 25 of 42 patients (60%), while the cfDNA assay detected mutations in 37 of 42 patients (88%). Our cfDNA assay detected mutations with allele frequencies as low as 0.01%. After exposure to treatment, 41 of 42 patients (98%) had a cfDNA-detected RAS/BRAF mutation. Of 21 patients followed with serial measurements who were RAS/BRAF mutant at baseline, 11 (52%) showed additional point mutation following treatment and 3 (14%) no longer had detectable levels of another mutant allele. Of RAS/BRAF wild-type tumors at baseline, 4 of 5 (80%) showed additional point mutations. cfDNA quantitative measurements from this study closely mirrored changes in CEA and CT scan results, highlighting the importance of obtaining quantitative data beyond the mere presence of a mutation.Conclusions: Our findings demonstrate the development of new RAS/BRAF mutations in patients regardless of whether they had preexisting mutations in the pathway, demonstrating a convergent evolutionary pattern. Clin Cancer Res; 23(16); 4578-91. ©2017 AACR.

4123 Background: Oleclumab is a human mAb that binds to CD73 and inhibits production of immunosuppressive adenosine. This is a first-in-human study to investigate the safety, efficacy, and pharmacodynamics of oleclumab alone or in combination with durvalumab in patients (pts) with advanced panc or MSS-CRC. Methods: A 3+3 dose-escalation design was followed in which pts received one of 4 escalating doses of oleclumab IV with or without durvalumab 10 mg/kg IV Q2W until disease progression, followed by study expansion with high dose of oleclumab plus durvalumab 10 mg/kg Q2W. AEs and tumor response (RECIST v1.1) were assessed. Free soluble CD73 and cell surface CD73 on lymphocytes were measured by ELISA and flow cytometry, respectively. Tumoral CD73 was centrally assessed by an in situ enzyme assay and IHC. Results: The initial dose-escalation and PD exploration enrolled 42 monotherapy and 24 combination pts with no reported DLTs. The minimum target serum concentration was exceeded at the top 2 doses. Sustained decrease in free soluble CD73 and CD73 on peripheral T cells was demonstrated across all doses and pts. Decreased CD73 enzymatic activity was observed in all evaluable frozen tumor biopsy samples (n = 4) 20 days after treatment with the top 2 doses of oleclumab. Treatment with oleclumab alone decreased tumoral CD73 expression (5/9) while increasing CD8+ TILs in all 5 samples. Subsequently, durva + oleclumab highest dose was selected for expansion in 2-5L CRC (21 pts) and 2-3L panc (20 pts). The most commonly reported TRAEs in combo expansion were diarrhea (8.7%), pyrexia (8.7%), fatigue (6.5%), and increases in ALT (6.5%), AST (6.5%), and ALP (6.5%). PR was observed for 1/21 CRC (5L) and 2/20 panc (2 and 3L) pts; SD was observed in 2/21 CRC and 3/20 panc pts. Duration of treatment for subjects with disease control was 84-322 days (CRC) and 28-232 days (panc). Treatment is ongoing for 1 CRC (322 days) and 2 panc pts (140 and 182 days). Conclusions: Treatment with oleclumab and durvalumab had a manageable safety profile and PD consistent with mechanism of action. Combination therapy has encouraging clinical activity in panc and potentially in CRC pts. Clinical trial information: 02503774.

Objective: We sought to identify potential radiologic and serologic markers of pancreatic tumor response to therapy, using pathologic major response (pMR) as the objective endpoint. Background: We previously demonstrated that a pMR to preoperative therapy, defined as detection of &lt;5% viable cancer cells in the surgical specimen on histopathological analysis, is an important prognostic factor for patients with pancreatic ductal adenocarcinoma (PDAC). Methods: Pretreatment and posttreatment computed tomography scans of consecutive patients who received preoperative chemotherapy and/or (chemo)radiation before pancreatectomy for PDAC between January 2010 and December 2018 were rereviewed. Response per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, other radiographic changes in tumor size and anatomic extent, and posttreatment CA 19-9 levels were compared between patients who did and did not have a pMR on final histopathologic analysis of their surgical specimens. Results: A total of 290 patients with localized PDAC underwent pancreatectomy between 2010 and 2018 after receiving preoperative chemotherapy (n = 36; 12%), (chemo)radiation (n = 87; 30%), or both (n = 167; 58%). Among them, 28 (10%) experienced pMR, including 9 (3.1%) who experienced pathologic complete response. On multivariable logistic regression, low posttreatment CA 19-9 level, RECIST partial response, and reduction in tumor volume were confirmed to be independently associated with pMR ( P &lt; 0.01). Conclusions: We identified serologic and radiographic indicators of pMR that could help inform the delivery of preoperative therapy to patients with PDAC.

The immunosuppressive desmoplastic stroma of pancreatic cancer represents a major hurdle to developing an effective immune response. Preclinical studies in pancreatic cancer have demonstrated promising anti-tumor activity with Bruton tyrosine kinase (BTK) inhibition combined with programmed cell death receptor-1 (PD-1) blockade.This was a phase II, multicenter, open-label, randomized (1:1) clinical trial evaluating the BTK inhibitor acalabrutinib, alone (monotherapy) or in combination with the anti-PD-1 antibody pembrolizumab (combination therapy). Eligible patients were adults with histologically confirmed metastatic or locally advanced unresectable pancreatic ductal adenocarcinoma with an Eastern Cooperative Oncology Group Performance Status (ECOG PS) ≤1 who had received at least one prior systemic therapy. Oral acalabrutinib 100 mg twice daily was administered with or without intravenous pembrolizumab 200 mg on day 1 of each 3-week cycle. Peripheral blood was analyzed for changes in immune markers, and tumors from exceptional responders were molecularly analyzed.A total of 77 patients were enrolled (37 monotherapy; 40 combination therapy) with a median age of 64 years; 77% had an ECOG PS of 1. The median number of prior therapies was 3 (range 1-6). Grade 3-4 treatment-related adverse events were seen in 14.3% of patients in the monotherapy arm and 15.8% of those in the combination therapy arm. The overall response rate and disease control rate were 0% and 14.3% with monotherapy and 7.9% and 21.1% with combination therapy, respectively. Median progression-free survival was 1.4 months in both arms. Peripheral blood flow analysis demonstrated consistent reductions in granulocytic (CD15+) myeloid-derived suppressor cells (MDSCs) over time. Two exceptional responders were found to be microsatellite stable with low tumor mutation burden, low neoantigen load and no defects in the homologous DNA repair pathway.The combination of acalabrutinib and pembrolizumab was well tolerated, but limited clinical activity was seen with either acalabrutinib monotherapy or combination therapy. Peripheral reductions in MDSCs were seen. Efforts to understand and target the pancreatic tumor microenvironment should continue.NCT02362048.

Many clinical trials supporting new drug applications underrepresent minority patients. Trials conducted by the National Cancer Institute's National Clinical Trial's Network (NCTN) have greater outreach to community sites, potentially allowing better representation. We compared the representation of Black patients in pharmaceutical company-sponsored cancer clinical trials with NCTN trials and with the US cancer population.We established a large cohort of study publications representing the results of trials that supported new US Food and Drug Administration drug approvals from 2008 to 2018. NCTN trial data were from the SWOG Cancer Research Network. US cancer population rates were estimated using Surveillance, Epidemiology, and End Results survey data. We compared the proportion of Black patients by enrollment year for each cancer type and overall. Tests of proportions were used. All statistical tests were 2-sided.A total 358 trials (pharmaceutical company-sponsored trials, 85; SWOG trials, 273) comprised of 93 825 patients (pharmaceutical company-sponsored trials, 46 313; SWOG trials, 47 512) for 15 cancer types were analyzed. Overall, the proportion of Black patients was 2.9% for pharmaceutical company-sponsored trials, 9.0% for SWOG trials, and 12.1% for the US cancer population (P < .001 for each pairwise comparison). These findings were generally consistent across individual cancer types.The poor representation of Black patients in pharmaceutical company-sponsored trials supporting new drug applications could result in the use of new drugs with little data about efficacy or side effects in this key population. Moreover, because pharmaceutical company-sponsored trials test the newest available therapies, limited access to these trials represents a disparity in access to potential breakthrough therapies.

<h3>Importance</h3> Direct intratumoral delivery of immunotherapies is a compelling approach to overcoming barriers to systemic immunotherapy efficacy. While the use of intratumoral delivery of immunotherapy drugs is increasing rapidly in both the investigational and standard of care domains, the feasibility and safety of these interventions, particularly for deeper lesions that require image-guidance, remain unknown. <h3>Objective</h3> To address current knowledge gaps in image-guided techniques for intratumoral immunotherapy delivery and the safety of these interventions. <h3>Design, Setting, and Participants</h3> This case series study was performed at a single tertiary cancer center over a 2-year period from January 2016 to January 2018. Patients were followed until January 2019. All patients who underwent image-guided intratumoral delivery of immunotherapy agents in the standard of care, off-label, or investigational setting during the study period were included. Data were analyzed from February 1 to June 1, 2019. <h3>Exposures</h3> Image-guided biopsies and intratumoral injections of immunotherapies across several clinical trials as well as standard of care talimogene laherparepvec therapy. <h3>Main Outcomes and Measures</h3> Technical success, defined as the delivery of the prescribed injectate volume in its entirety, for image-guided biopsy and injections and procedure-related adverse events. <h3>Results</h3> A total of 85 patients (median [interquartile range] age, 61 [47-71] years; 42 [52%] men) underwent 498 encounters during the study period. These encounters comprised 327 image-guided intratumoral investigational agent injections in 67 patients in clinical trials, including 33 patients with melanoma (50%), 14 patients with sarcoma (21%), 3 patients with ovarian cancer (4.5%), 2 patients with breast cancer (3%), and 2 patients with colon cancer (3%). An additional 18 patients with melanoma underwent 113 image-guided talimogene laherparepvec injections. There were no adverse events reported related to the technical component of the procedure, specifically needle insertion or biopsy. Serious adverse events (Common Terminology Criteria for Adverse Events score ≥3), including dyspnea and severe flu-like symptoms developing within 24 hours of the injection and requiring hospitalization, occurred after 3 of 327 investigational agent injections (2%) and 4 of 113 talimogene laherparepvec injections (4%). <h3>Conclusions and Relevance</h3> The findings of this case series study suggest that intratumoral injections of immunotherapies were feasible across a range of histological conditions and target organs. Immediate postdelivery anticipated adverse events occurred in a small number of instances. Performing physicians should have the necessary safeguards in place to respond as needed. Optimal methods for intratumoral drug delivery remain unresolved, and efforts to standardize drug delivery techniques are required.

Abstract Immune checkpoint inhibition (CPI) for metastatic colorectal cancer (mCRC) with deficient mismatch repair (dMMR) demonstrates high clinical activity that appears durable, but the impact of CPI on pathological tumor response is unknown. In this retrospective analysis, our objective was to assess pathological response and clinical outcomes in dMMR mCRC patients treated with CPI prior to surgical resection of primary and/or metastatic tumor. Among 121 advanced dMMR mCRC patients treated with CPI at 2 institutions between November 2016 and December 2018, 14 underwent surgery. Pathologic complete response was noted in the resected specimens of 13 patients despite the presence of residual tumor on preoperative imaging in 12 of those patients. With median follow-up of 9 months, no patients have had disease relapse or progression. For this small retrospective study, the data suggest that residual radiographic tumor may not require systematic resection following response to anti-PD1–based therapy. However, larger prospective studies are warranted.

KRAS p.G12C mutations occur in approximately 3% of metastatic colorectal cancers (mCRC). Recently, two allosteric inhibitors of KRAS p.G12C have demonstrated activity in early phase clinical trials. There are no robust studies examining the behavior of this newly targetable population.We queried the MD Anderson Cancer Center data set for patients with colorectal cancer who harbored KRAS p.G12C mutations between January 2003 and September 2019. Patients were analyzed for clinical characteristics, overall survival (OS), and progression-free survival (PFS) and compared against KRAS nonG12C. Next, we analyzed several internal and external data sets to assess immune signatures, gene expression profiles, hypermethylation, co-occurring mutations, and proteomics.Among the 4,632 patients with comprehensive molecular profiling, 134 (2.9%) were found to have KRAS p.G12C mutations. An additional 53 patients with single gene sequencing were included in clinical data but excluded from prevalence analysis allowing for 187 total patients. Sixty-five patients had de novo metastatic disease and received a median of two lines of chemotherapy without surgical intervention. For the first three lines of chemotherapy, the median PFS was 6.4 months (n = 65; 95% CI, 5.0 to 7.4 months), 3.9 months (n = 47; 95% CI, 2.9 to 5.9 months), and 3.0 months (n = 21; 95% CI, 2.0 to 3.4 months), respectively. KRAS p.G12C demonstrated higher rates of basal EGFR activation compared with KRAS nonG12C. When compared with an internal cohort of KRAS nonG12C, KRAS p.G12C patients had worse OS.PFS is poor for patients with KRAS p.G12C metastatic colorectal cancer. OS was worse in KRAS p.G12C compared with KRAS nonG12C patients. Our data highlight the innate resistance to chemotherapy for KRAS p.G12C patients and serve as a historical comparator for future clinical trials.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the leading causes of cancer-related deaths in the world. For patients with PDAC who are not eligible for surgery, radiation therapy improves local disease control, yet safely delivering therapeutic doses of radiation remains challenging due to off-target toxicities in surrounding normal tissues. NBTXR3, a novel radioenhancer composed of functionalized hafnium oxide crystalline nanoparticles, has recently shown clinical activity in soft tissue sarcoma, hepatocellular carcinoma, head and neck squamous cell carcinoma, and advanced solid malignancies with lung or liver metastases. Here we report the first patient with pancreatic cancer treated with NBTXR3.A 66-year-old male with unresectable locally advanced PDAC was enrolled on our clinical trial to receive NBTXR3 activated by radiation therapy. Local endoscopic delivery of NBTXR3 was followed by intensity modulated radiation therapy (IMRT). Follow-up assessment consisted of physical examination, laboratory studies including CA19-9, and CT of the chest, abdomen, and pelvis.The patient received NBTXR3 by local endoscopic delivery without any acute adverse events. Radiation treatment consisted of 45 Gy in 15 daily fractions using IMRT. The patient began radiation twelve days after NBTXR3 injection. Daily CT-on-rails imaging demonstrated retention of NBTXR3 within the tumor for the duration of treatment. At initial follow-up evaluation, the lesion remained radiographically stable and the patient did not demonstrate treatment-related toxicity.This report demonstrates initial feasibility of local endoscopic delivery of NBTXR3 activated by radiation therapy for patients with pancreatic cancer who are not eligible for surgery.

Upon chronic antigen exposure, CD8+ T cells become exhausted, acquiring a dysfunctional state correlated with the inability to control infection or tumor progression. In contrast, stem-like CD8+ T progenitors maintain the ability to promote and sustain effective immunity. Adenovirus (Ad)-vectored vaccines encoding tumor neoantigens have been shown to eradicate large tumors when combined with anti-programmed cell death protein 1 (αPD-1) in murine models; however, the mechanisms and translational potential have not yet been elucidated. Here, we show that gorilla Ad vaccine targeting tumor neoepitopes enhances responses to αPD-1 therapy by improving immunogenicity and antitumor efficacy. Single-cell RNA sequencing demonstrated that the combination of Ad vaccine and αPD-1 increased the number of murine polyfunctional neoantigen-specific CD8+ T cells over αPD-1 monotherapy, with an accumulation of Tcf1+ stem-like progenitors in draining lymph nodes and effector CD8+ T cells in tumors. Combined T cell receptor (TCR) sequencing analysis highlighted a broader spectrum of neoantigen-specific CD8+ T cells upon vaccination compared to αPD-1 monotherapy. The translational relevance of these data is supported by results obtained in the first 12 patients with metastatic deficient mismatch repair (dMMR) tumors vaccinated with an Ad vaccine encoding shared neoantigens. Expansion and diversification of TCRs were observed in post-treatment biopsies of patients with clinical response, as well as an increase in tumor-infiltrating T cells with an effector memory signature. These findings indicate a promising mechanism to overcome resistance to PD-1 blockade by promoting immunogenicity and broadening the spectrum and magnitude of neoantigen-specific T cells infiltrating tumors.

CD73 upregulation in tumors leads to local immunosuppression. This phase I, first-in-human study evaluated oleclumab (MEDI9447), an anti-CD73 human IgG1λ monoclonal antibody, alone or with durvalumab in patients with advanced colorectal cancer (CRC), pancreatic ductal adenocarcinoma (PDAC), or epidermal growth factor receptor-mutant non-small-cell lung cancer (NSCLC).Patients received oleclumab 5-40 mg/kg (dose-escalation) or 40 mg/kg (dose-expansion) intravenously every 2 weeks (Q2W), alone (escalation only) or with durvalumab 10 mg/kg intravenously Q2W.192 patients were enrolled, 66 during escalation and 126 (42 CRC, 42 PDAC, 42 NSCLC) during expansion. No dose-limiting toxicities occurred during escalation. In the monotherapy and combination therapy escalation cohorts, treatment-related adverse events (TRAEs) occurred in 55 and 54%, respectively, the most common being fatigue (17 and 25%). In the CRC, PDAC, and NSCLC expansion cohorts, 60, 57, and 45% of patients had TRAEs, respectively; the most common were fatigue (15%), diarrhea (9%), and rash (7%). Free soluble CD73 and CD73 expression on peripheral T cells and tumor cells showed sustained decreases, accompanied by reduced CD73 enzymatic activity in tumor cells. Objective response rate during escalation was 0%. Response rates in the CRC, PDAC, and NSCLC expansion cohorts were 2.4% (1 complete response [CR]), 4.8% (1 CR, 1 partial response [PR]), and 9.5% (4 PRs), respectively; 6-month progression-free survival rates were 5.4, 13.2, and 16.0%.Oleclumab ± durvalumab had a manageable safety profile, with pharmacodynamic activity reflecting oleclumab's mechanism of action. Evidence of antitumor activity was observed in tumor types that are generally immunotherapy resistant.Clinicaltrials.gov, NCT02503774; date of registration, July 17, 2015.

This discussion summarizes the NCCN Clinical Practice Guidelines for managing squamous cell anal carcinoma, which represents the most common histologic form of the disease. A multidisciplinary approach including physicians from gastroenterology, medical oncology, surgical oncology, radiation oncology, and radiology is necessary. Primary treatment of perianal cancer and anal canal cancer are similar and include chemoradiation in most cases. Follow-up clinical evaluations are recommended for all patients with anal carcinoma because additional curative-intent treatment is possible. Biopsy-proven evidence of locally recurrent or persistent disease after primary treatment may require surgical treatment. Systemic therapy is generally recommended for extrapelvic metastatic disease. Recent updates to the NCCN Guidelines for Anal Carcinoma include staging classification updates based on the 9th edition of the AJCC Staging System and updates to the systemic therapy recommendations based on new data that better define optimal treatment of patients with metastatic anal carcinoma.

Appendiceal adenocarcinoma is a rare tumor, and given the inherent difficulties in performing prospective trials in such a rare disease, there are currently minimal high-quality data to guide treatment decisions, highlighting the need for more preclinical and clinical investigation for this disease.To prospectively evaluate the effectiveness of fluoropyrimidine-based systemic chemotherapy in patients with inoperable low-grade mucinous appendiceal adenocarcinoma.This open-label randomized crossover trial recruited patients at a single tertiary care comprehensive cancer center from September 2013 to January 2021. The data collection cutoff was May 2022. Enrollment of up to 30 patients was planned. Eligible patients had histological evidence of a metastatic low-grade mucinous appendiceal adenocarcinoma, with radiographic imaging demonstrating the presence of mucinous peritoneal carcinomatosis and were not considered candidates for complete cytoreductive surgery. Key exclusion criteria were concurrent or recent investigational therapy, evidence of bowel obstruction, and use of total parenteral nutrition. Data were analyzed from November 2021 to May 2022.Patients were randomized to either 6 months observation followed by 6 months of chemotherapy, or initial chemotherapy followed by observation.The primary end point was the percentage difference in tumor growth in treatment and observation groups. Key secondary end points included patient-reported outcomes in the chemotherapy and observation periods, objective response rate, rate of bowel complications, and differences in overall survival (OS).A total of 24 patients were enrolled, with median (range) age of 63 (38 to 82) years, and equal proportion of men and women (eg, 12 men [50%]); all patients had ECOG performance status of 0 or 1. A total of 11 patients were randomized to receive chemotherapy first, and 13 patients were randomized to receive observation first. Most patients (15 patients [63%]) were treated with either fluorouracil or capecitabine as single agent; 3 patients (13%) received doublet chemotherapy (leucovorin calcium [folinic acid], fluorouracil, and oxaliplatin or folinic acid, fluorouracil, and irinotecan hydrochloride), and bevacizumab was added to cytotoxic chemotherapy for 5 patients (21%). Fifteen patients were available to evaluate the primary end point of difference in tumor growth during treatment and observation periods. Tumor growth while receiving chemotherapy increased 8.4% (95% CI, 1.5% to 15.3%) from baseline but was not significantly different than tumor growth during observation (4.0%; 95% CI, -0.1% to 8.0%; P = .26). Of 18 patients who received any chemotherapy, none had an objective response (14 patients [77.8%] had stable disease; 4 patients [22.2%] had progressive disease). Median (range) OS was 53.2 (8.1 to 95.5) months, and there was no significant difference in OS between the observation-first group (76.0 [8.6 to 95.5] months) and the treatment-first group (53.2 [8.1 to 64.1] months; hazard ratio, 0.64; 95% CI, 0.16-2.55; P = .48). Patient-reported quality-of-life metrics identified that during treatment, patients experienced significantly worse fatigue (mean [SD] score, 18.5 [18.6] vs 28.9 [21.3]; P = .02), peripheral neuropathy (mean [SD] score, 6.67 [12.28] vs 38.89 [34.88]; P = .01), and financial difficulty (mean [SD] score, 8.9 [15.2] vs 28.9 [33.0]; P = .001) compared with during observation.In this prospective randomized crossover trial of systemic chemotherapy in patients with low-grade mucinous appendiceal adenocarcinoma, patients did not derive clinical benefit from fluorouracil-based chemotherapy, given there were no objective responses, no difference in OS when treatment was delayed 6 months, and no difference in the rate of tumor growth while receiving chemotherapy.ClinicalTrials.gov Identifier: NCT01946854.

We pooled data from 2 cohorts of immune checkpoint inhibitors-treated microsatellite instability-high/mismatch repair-deficient (MSI/dMMR) metastatic colorectal cancer patients to evaluate the prognostic value of RAS/BRAFV600E mutations and Lynch syndrome (LS).Patients were defined as LS-linked if germline mutation was detected and as sporadic if loss of MLH1/PMS2 expression with BRAFV600E mutation and/or MLH1 promoter hypermethylation, or biallelic somatic MMR genes mutations were found. Progression-free survival (PFS) and overall survival (OS) were adjusted on prognostic modifiers selected on unadjusted analysis (P < .2) if limited number of events.Of 466 included patients, 305 (65.4%) and 161 (34.5%) received, respectively, anti-PD1 alone and anti-PD1+anti-CTLA4 in the total population, 111 (24.0%) were treated in first-line; 129 (28.8%) were BRAFV600E-mutated and 153 (32.8%) RAS-mutated. Median follow-up was 20.9 months. In adjusted analysis of the whole population (PFS/OS events = 186/133), no associations with PFS and OS were observed for BRAFV600E-mutated (PFS HR= 1.20, P = .372; OS HR = 1.06, P = .811) and RAS-mutated patients (PFS HR = 0.93, P = .712, OS HR = 0.75, P = .202). In adjusted analysis in the Lynch/sporadic status-assigned population (n = 242; PFS/OS events = 80/54), LS-liked patients had an improved PFS compared to sporadic cases (HR = 0.49, P = .036). The adjusted HR for OS was 0.56 with no significance (P = .143). No adjustment on BRAFV600E mutation was done due to collinearity.In this cohort, RAS/BRAFV600E mutations were not associated with survival while LS conferred an improved PFS.

Despite having a dramatically larger surface area than the large intestine, the small intestine is an infrequent site for the development of adenocarcinoma. To better understand the molecular abnormalities in small bowel adenocarcinoma (SBA), we characterised a number of candidate oncogenic pathways and the immunophenotype of this rare cancer.Tissue microarrays were constructed from tumour samples from 54 patients with all stages of the disease. Immunohistochemistry and microsatellite instability (MSI) testing were conducted.The profile of cytokeratin 20 and 7 coexpression was variable, but expression of caudal type homeobox transcription factor 2 (CDX2) was present in 70% of cases. In this young population (median age 54 years), loss of mismatch repair (MMR) proteins occurred in 35% of patients, with confirmed MSI in 100% of tested cases. Expression of vascular endothelial growth factor-A (VEGF-A) and epidermal growth factor receptor (EGFR) was common, occurring in 96 and 71% of patients, respectively. Only one case showed HER2 expression and none showed loss of phosphatase and tensin homologue mutated on chromosome 10 (PTEN).These results suggest that alterations in DNA MMR pathways are common in SBAs, similar to what is observed in large bowel adenocarcinomas. Furthermore, the high percentage of tumours expressing both EGFR and VEGF suggests that patients with this rare cancer may benefit from therapeutic strategies targeting EGFR and VEGF receptor (VEGFR).

Abstract BACKGROUND. Metastatic small bowel adenocarcinoma (SBA) has a poor prognosis. Because of the rarity of SBA, only a few studies have evaluated the role of chemotherapy in the treatment of metastatic SBA; thus, the benefit, if any, of adding a platinum compound to fluorouracil (5‐FU) is unknown. The objective of this retrospective study was to determine whether the addition of a platinum compound to 5‐FU provided any benefit in the treatment of patients with metastatic SBA. METHODS. The authors identified 80 patients with metastatic SBA who were treated with chemotherapy at the University of Texas M. D. Anderson Cancer Center between 1978 and 2005. Response rates, progression‐free survival (PFS), and overall survival (OS) were compared between patients who received 5‐FU and a platinum compound and patients who received other chemotherapy combinations. RESULTS. The median patient age was 53 years. The primary tumor site was the jejunum in 35 patients (43%), duodenum in 30 patients (38%), ileum in 6 patients (8%), and nonspecified small bowel in 9 patients (11%). Of all 80 patients, 29 patients (36%) received 5‐FU and a platinum compound, 41 patients (51%) received 5‐FU without a platinum compound, and 10 patients (13%) received non‐5‐FU–based treatment. Compared with other chemotherapy regimens, treatment with 5‐FU and a platinum agent resulted in a higher response rate (46% vs 16% with other regimens; P = .01) and longer median PFS (8.7 months vs 3.9 months; P ≤ .01) but not better OS (14.8 months vs 12 months; P = .1). In multivariate analysis, treatment with 5‐FU and a platinum compound was a significant predictor of response (odds ratio, 4.5; 95% confidence interval [CI], 1.3‐15.8; P = .02) and PFS (hazard ratio. 0.49; 95% CI, 0.29‐0.84; P = .01) but only reached borderline significance for OS (hazard ratio, 0.63; 95% CI, 0.37‐1.07; P = .08). CONCLUSIONS. To the authors' knowledge, the current analysis represents the largest number of patients with metastatic SBA treated with chemotherapy in the literature, and the results suggested that the combination of 5‐FU and a platinum compound leads to a higher response rate and PFS compared with other chemotherapy regimes. The authors concluded that prospective investigation of platinum analogues in the treatment of SBA is warranted. Cancer 2008. © 2008 American Cancer Society.

Appendiceal neoplasms include tumors ranging from benign-appearing cells with widespread mucin deposits to aggressive poorly differentiated signet ring cell adenocarcinomas. Traditionally, these tumors are treated with cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy. For some patients, cytoreductive surgery is not an option, and minimal published data exist in the management and outcome of these patients. A retrospective analysis was conducted to determine the benefit of modern systemic chemotherapy in patients with disseminated appendiceal neoplasm who were not considered optimal candidates for cytoreductive surgery.A retrospective review was conducted using The University of Texas M. D. Anderson Cancer Center tumor registry between January 2000 and July 2005. Response was determined by radiographic response and/or overall clinical benefit.Of 186 patients diagnosed with appendiceal neoplasm, 54 (29%) patients considered to be suboptimal surgical candidates received > or =2 cycles of systemic chemotherapy. Thirty (55.6%) patients had a disease control rate noted as a complete response, partial response, or stable disease. After a median follow-up of 24 months, the median progression-free survival (PFS) and overall survival were determined to be 7.6 months (95% confidence interval [CI], 4-11) and 56 months (95% CI, 36-not applicable), respectively.Systemic chemotherapy has a role in appendiceal neoplasm patients who are suboptimal candidates for cytoreductive surgery. The intermediate PFS indicates the challenges that exist for appendiceal neoplasm patients in this setting. Prospective randomized trials including systemic chemotherapy are needed to provide further insight into this malignancy, for which no standard exists.

Oxaliplatin-based chemotherapy regimens are currently a standard of care for the treatment of colorectal cancer (CRC) in both the adjuvant treatment and metastatic disease settings. Significant improvements in outcomes have been achieved with oxaliplatin-based combinations in these settings when compared with administration of 5-fluorouracil alone. Pathologic evaluation of normal liver from patients undergoing neoadjuvant oxaliplatin treatment has identified histologic evidence of sinusoidal injury, although the effect of this finding on patient outcomes after hepatic resection appears to be minimal. This article describes the use of oxaliplatin-based chemotherapy in 6 patients with stage III or IV CRC who developed evidence of noncirrhotic portal hypertension. These patients developed complications of portal hypertension including esophageal or hemorrhoidal varices with bleeding, splenomegaly with associated thrombocytopenia, and ascites. In each case, oxaliplatin-induced hepatic sinusoidal injury was identified as the most likely factor contributing to the development of noncirrhotic portal hypertension. The literature on hepatic sinusoidal injury after oxaliplatin is reviewed and the proposed pathophysiology is discussed.

The presence of distant metastases and the completeness of resection are important prognostic factors in patients with small bowel adenocarcinoma (SBA); however, the influence of lymph node metastasis on patient outcome has not been well characterized. The objective of the current study was to evaluate the impact of the number of positive and negative lymph nodes on survival after curative resection.Patients who had SBA diagnosed between 1988 and 2005 were identified from the Surveillance, Epidemiology, and End Results (SEER) registry. Cox proportional hazards regression analyses were performed after adjusting for age, sex, race, tumor stage, tumor grade, and primary site. Five-year disease-specific survival (DSS) was determined, all patients were categorized according to the total lymph nodes (TLNs) assessed, and patients with stage III disease also were categorized according to the number of positive lymph nodes (PLNs) and the PLN-to-TLN ratio (the lymph node ratio [LNR]).In total, 1991 patients (n=1216 with stage I/II SBA and n=775 with stage III SBA) were analyzed. Survival depended on the TLNs assessed. The 5-year DSS rate for patients with stage II disease was associated with the TLNs assessed (44%, 69%, and 83% for 0 TLNs, 1-7 TLNs, and>7 TLNs, respectively). The 5-year DSS for patients with stage III disease was associated with the number of PLNs (58% and 37% for <3 PLNs and ≥3 PLNs, respectively). Among patients with stage III disease, the LNR was even more predictive of survival than stratification by the number of PLNs.Survival after surgical resection for stage I, II, and III SBA was associated with the TLNs assessed. Stratifying patients with stage III disease into those with <3 PLNs and ≥3 PLNs significantly improved prognostication.

Chemotherapy-induced peripheral neuropathy is frequently a dose-limiting factor in cancer treatment and may cause pain and irreversible function loss in cancer survivors. We tested whether alpha-lipoic acid (ALA) could decrease the severity of peripheral neuropathy symptoms in patients undergoing platinum-based chemotherapy. Cancer patients 18 years or older were randomly selected to receive either 600 mg ALA or a placebo three times a day orally for 24 weeks while receiving chemotherapy regimens including cisplatin or oxaliplatin. Neuropathy was measured by the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) scale and the NCI Common Toxicity Criteria for Adverse Events neurotoxicity grades. Results from timed functional tests and the Brief Pain Inventory (BPI) were secondary endpoints. Seventy of 243 (29 %) patients completed the study (24 weeks). Both the ALA and the placebo arms had a comparable drop-out rate. No statistically significant differences were found between the ALA and the placebo groups for FACT/GOG-Ntx scores, BPI scores, and patients' functional outcomes. This strategy of oral ALA administration was ineffective at preventing neurotoxicity caused by oxaliplatin or cisplatin. High attrition rates due to poor patient compliance and manner of dosage administration in this trial demonstrated a lack of feasibility for this intervention. Future studies to explore ALA as a neuroprotective agent should take heed of the barriers confronted in this study.

KRAS mutations have been associated with lung metastases at diagnosis of metastatic colorectal cancer (mCRC), but the impact of this mutation on subsequent development of lung metastasis is unknown. We investigated KRAS mutation as a predictor of lung metastasis development.We retrospectively evaluated data from patients with mCRC whose tumour was tested for KRAS mutation from 2008 to 2010. The relationships of KRAS mutational status with time-to-lung metastasis (TTLM) and overall survival (OS) were analysed.Of the 494 patients identified, 202 (41%) had tumours with KRAS mutation. KRAS mutations were associated with a shorter TTLM (median 15.2 vs 22.4 months; hazard ratio=1.40; P=0.002) and a two-fold greater odds of developing lung metastases during the disease course in patients with liver-limited mCRC at diagnosis (72 vs 56%, P=0.007). Overall survival did not differ by KRAS status.Lung metastasis was more likely to develop during the disease course in patients whose tumour had a KRAS mutation than in those whose tumour did not have a KRAS mutation. This finding may have an impact on decision making for surgical resection of metastatic disease.

Purpose This study assessed the efficacy of methylphenidate versus placebo for cancer-related fatigue reduction. Other objectives were to analyze cytokine levels and to determine the effects of methylphenidate on other symptoms, cognitive function, work yield, and patients’ perceptions and preferences. Methods Patients were randomly assigned (1:1) to receive methylphenidate-placebo or placebo-methylphenidate for 4 weeks. Patients crossed over after 2 weeks. Wilcoxon signed rank tests and McNemar tests were used to assess continuous and categorical variables. The primary efficacy endpoint was change in the level of worst fatigue on the Brief Fatigue Inventory (BFI) at the end of each 2-week period. Results The mean baseline BFI score was moderate (5.7). Methylphenidate treatment did not affect patients’ worst level of fatigue or other symptoms. Results from the Wechsler Adult Intelligence Scale Digit Symbol Test and the Hopkins Verbal Learning Test with BFI interference questions and BFI activity questions showed significant improvement in the methylphenidate-treated patients’ verbal learning, memory, visual perception, analysis, and scanning speed. Patients treated with methylphenidate missed significantly fewer work hours owing to health reasons and worked significantly more hours. After 4 weeks, 64% of patients reported that methylphenidate improved their cancer-related fatigue, and 58% wanted to continue treatment. Significant difference in interleukin 6R (positive), interleukin 10 (negative), and tumor necrosis factor α (positive) was noted between the methylphenidate and the placebo group. Conclusions Low-dose methylphenidate did not improve cancer-related fatigue. Patients taking methylphenidate had better cognition and were able to work more hours. Patients tolerated methylphenidate well, and the majority felt better and wanted to continue treatment.

In Brief Objective: We hypothesized that metachronous colorectal liver metastases (CLM) have different biology after failure of oxaliplatin (FOLFOX) compared to 5-fluorouracil (5-FU) or no chemotherapy for adjuvant treatment of colorectal cancer (CRC). Background: It is unclear whether patients treated with liver resection for metachronous CLM after adjuvant FOLFOX for CRC have worse outcomes than those who received 5-FU or no chemotherapy. Methods: We identified 341 patients who underwent hepatectomy for metachronous CLM (disease-free interval ≥12 months, 1993–2010). Mass-spectroscopy genotyping for somatic gene mutations in CLM was performed in a subset of 129 patients. Results: Adjuvant treatment for primary CRC was FOLFOX in 77 patients, 5-FU in 169 patients, and no chemotherapy in 95 patients. Node-positive primary was comparable between FOLFOX and 5-FU but lower in the no-chemotherapy group (P < 0.0001). Median metastasis size was smaller in the FOLFOX group (2.5 cm) than in the 5-FU (3.0 cm) or no-chemotherapy (3.5 cm) groups, (P = 0.008) although prehepatectomy chemotherapy utilization, metastases number, and carcinoembryonic antigen levels were similar. Disease-free survival (DFS) and overall survival (OS) rates after hepatectomy were worse in patients treated with adjuvant FOLFOX [DFS at 3 years: 14% vs 38% (5-FU) vs 45% (no-chemo), OS at 3 years: 58% vs 70% (5-FU) vs 84% (no-chemo)]. On multivariate analysis, adjuvant FOLFOX was associated with worse DFS (P < 0.0001) and OS (P < 0.0001). Mutation analysis revealed ≥1 mutations in 57% of patients (27/47) after FOLFOX, 29% (12/41) after 5-FU, and 32% (13/41) after no chemotherapy (P = 0.011). Conclusions: Adjuvant FOLFOX for primary CRC is associated with a high rate of somatic mutations in liver metastases and inferior outcomes after hepatectomy for metachronous CLM. Outcomes and frequency of somatic gene mutations were analyzed by the adjuvant chemotherapy type for colorectal cancer (CRC) in patients treated with hepatectomy for metachronous colorectal liver metastases (CLM). Adjuvant FOLFOX for CRC is associated with a high rate of somatic mutations in metachronous CLM and inferior outcomes after hepatectomy.

SMAD4 is an essential mediator in the transforming growth factor-β pathway. Sporadic mutations of SMAD4 are present in 2.1–20.0% of colorectal cancers (CRCs) but data are limited. In this study, we aimed to evaluate clinicopathologic characteristics, prognosis, and clinical outcome associated with this mutation in CRC cases. Data for patients with metastatic or unresectable CRC who underwent genotyping for SMAD4 mutation and received treatment at The University of Texas MD Anderson Cancer Center from 2000 to 2014 were reviewed. Their tumors were sequenced using a hotspot panel predicted to cover 80% of the reported SMAD4 mutations, and further targeted resequencing that included full-length SMAD4 was performed on mutated tumors using a HiSeq sequencing system. Using The Cancer Genome Atlas data on CRC, the characteristics of SMAD4 and transforming growth factor-β pathway mutations were evaluated according to different consensus molecular subtypes of CRC. Among 734 patients with CRC, 90 (12%) had SMAD4 mutations according to hotspot testing. SMAD4 mutation was associated with colon cancer more so than with rectal cancer (odds ratio 2.85; p<0.001), female sex (odds ratio 1.71; p = 0.02), and shorter overall survival than in wild-type SMAD4 cases (median, 29 months versus 56 months; hazard ratio 2.08; p<0.001 [log-rank test]). SMAD4 mutation was not associated with age, stage at presentation, colonic location, distant metastasis, or tumor grade. A subset of patients with metastatic CRC (n = 44) wild-type for KRAS, NRAS, and BRAF who received anti-epidermal growth factor receptor therapy with mutated SMAD4 (n = 13) had shorter progression-free survival duration than did patients wild-type for SMAD4 (n = 31) (median, 111 days versus 180 days; p = 0.003 [log-rank test]). Full-length sequencing confirmed that missense mutations at R361 and P356 in the MH2 domain were the most common SMAD4 alterations. In The Cancer Genome Atlas data, SMAD4 mutation frequently occurred with KRAS, NRAS, and BRAF mutations and was more common in patients with the consensus molecular subtype 3 of CRC than in those with the other 3 subtypes. This is one of the largest retrospective studies to date characterizing SMAD4 mutations in CRC patients and demonstrates the prognostic role and lack of response of CRC to anti-epidermal growth factor receptor therapy. Further studies are required to validate these findings and the role of SMAD4 mutation in CRC.

3517 Background: HER2 amplification (HERamp), seen in 5% of KRAS wildtype (WT) metastatic colorectal cancers (mCRC), is associated with resistance to anti-epidermal growth factor receptor antibodies (antiEGFRabs). The purpose of this study was to validate the predictive impact of HERamp in mCRC. Methods: We performed systematic analyses of RAS and BRAF WT mCRC patients (pts) across 2 distinct cohorts. We tested HERamp in cohort 1 (N = 97) using immunohistochemistry and dual in-situ hybridization (HERamp: HER2/CEP17 ≥ 2.2). We validated these findings in cohort 2 (N = 99), which comprised of 37 cases of HERamp mCRC pts identified by next-generation sequencing (HERamp: ≥ 4 copies) and 62 HER2 non-amplified (HER2NA) pts treated previously with antiEGFRabs who served as controls. The primary objective was to compare progression-free survival (PFS) in pts treated with antiEGFRabs. PFS and overall survival (OS) were estimated using Kaplan Meier method and compared using log rank test. Results: HERamp was seen in 14 (14 %) of RAS/BRAF WT pts in cohort 1. In this cohort, median OS (29.1 v 45.1 months (m), P = 0.78) and PFS on first line therapy without an antiEGFRab (PFS1) (9.7 v 8.4 m, P = 0.70) was similar between HERamp and HER2NA pts. A total of 66 pts in cohort 1 received antiEGFRab after first line therapy. Median PFS on antiEGFRab therapy (PFS2) was significantly shorter in pts with HERamp compared to HER2NA tumors (2.9 v 8.1 m, hazard ratio (HR) 5.0, P < 0.0001). These findings were confirmed in cohort 2, in which 69 pts received antiEGFRab after first line therapy and median PFS2 was significantly shorter for HERamp pts compared to HER2NA pts (2.8 v 9.3 m, HR 6.6, P < 0.0001) with a similar OS (P = 0.86) and PFS1 (P = 0.62). Conclusions: HER2 amplification in mCRC is a predictive biomarker for lack of efficacy of antiEGFRab therapy. This magnitude of effect is comparable to RAS mutations; the only other validated predictive biomarker for antiEGFRabs, and affects 1 in 8 patients currently receiving these agents. Patients with RAS/RAF WT mCRC should be screened for HER2 amplification prior to treatment with antiEGFRabs and should be considered for early referral to clinical trials.

Background: In previously chemotherapy-treated patients with MSI-H/dMMR mCRC from the phase II CheckMate-142 trial, NIVO + low-dose IPI (1 mg/kg) provided durable clinical benefit (investigator-assessed [INV] objective response rate [ORR] 55%, median duration of response [DOR] not reached, 12-month overall survival [OS] rate 85%) and manageable safety. Here we report the first results of the efficacy and safety of NIVO + low-dose IPI as a first-line (1L) therapy for patients with MSI-H/dMMR mCRC from CheckMate-142. Methods: Patients with no prior treatment for MSI-H/dMMR mCRC were treated with NIVO 3 mg/kg every 2 weeks (Q2W) + low-dose IPI every 6 weeks (Q6W) until disease progression. The primary endpoint was ORR (INV; RECIST v1.1). Results: Of 45 patients, 51% were male and median age was 66 years. Median follow-up (time from first dose to data cut-off) was 13.8 months (range 9–19). The ORR and disease control rate (DCR) were 60% and 84%, respectively, with a 7% complete response rate (Table). Median DOR was not reached. At 12 months, progression-free survival (PFS) and OS rates were 77% and 83%, respectively. Grade 3–4 treatment-related adverse events (TRAEs) occurred in 16% of patients and 7% of patients had any grade TRAEs leading to discontinuation. Any grade select immune-mediated TRAEs affecting the hepatic (13%), gastrointestinal (11%), pulmonary (2%), and renal (2%) systems resolved in 100% of patients, while those affecting the skin (33%) and endocrine (24%) systems resolved in 45% and 60% of patients, respectively. Conclusions: NIVO (Q2W) + low-dose IPI (Q6W) demonstrated robust and durable clinical benefit and was well-tolerated as a 1L treatment for MSI-H/dMMR mCRC. These results suggest that NIVO + low-dose IPI may represent a new treatment option for these patients.Table: LBA18_PREfficacy and safetyNIVO + IPI (N = 45)ORRaPatients with CR or PR divided by the number of treated patients, n (%) (95% CI)27 (60) (44–74)Best overall response, n (%) CR PR SD PD Not determined3 (7) 24 (53) 11 (24) 6 (13) 1 (2)DCRbPatients with a CR, PR, or SD for ≥12 weeks divided by the number of treated patients CI = confidence interval; CR = complete response; NE = not estimable; NR = not reached; PD = progressive disease; PR = partial response; SD = stable disease, n (%) (95% CI)38 (84) (71–94)Median time to response, months (range)2.6 (1.2–13.8)Median DOR, months (95% CI)NR (11.5–NE)Median PFS, months (95% CI) 12-month rate, % (95% CI)NR (14.1–NE) 77 (62.0–87.2)Median OS, months (95% CI) 12-month rate, % (95% CI)NR (NE) 83 (67.6–91.7)TRAEs, n (%) Any grade Grade 3–435 (78) 7 (16)TRAEs leading to discontinuation, n (%) Any grade Grade 3–43 (7) 1 (2)a Patients with CR or PR divided by the number of treated patientsb Patients with a CR, PR, or SD for ≥12 weeks divided by the number of treated patients CI = confidence interval; CR = complete response; NE = not estimable; NR = not reached; PD = progressive disease; PR = partial response; SD = stable disease Open table in a new tab Clinical trial identification: NCT02060188. Editorial acknowledgement: Professional medical writing assistance and editorial assistance was provided by Tanmayi Mankame, PhD, and Christine Craig of Parexel International, funded by Bristol-Myers Squibb. Legal entity responsible for the study: Bristol-Myers Squibb. Funding: Bristol-Myers Squibb. Disclosure: H-J.J. Lenz: Honoraria: Bayer, Boehringer Ingelheim, Merck Serono, Roche; Consulting or advisory role: Bayer, Merck Serono, Pfizer, Roche; Travel, accommodations, expenses: Bayer, Merck Serono, Roche. E. Van Cutsem: Grants: Amgen, Bayer, BMS, Boehringer, Celgene, Ipsen, Lilly, Merck, MSD, Novartis, Roche, Servier; Honoraria: Bayer, BMS, Celgene, Lilly, Novartis, Servier. K.Y. Wong: Consultant/advisory role: Baxalta; Honoraria: Baxalta; Travel, accommodations, expenses: Roche. M. Aglietta: Honoraria: Bristol-Myers Squibb; Consulting or advisory role: Bristol-Myers Squibb; Travel, accommodations, expenses: Bristol-Myers Squibb. B. Neyns: Honoraria: BMS, Merck, Novartis, Roche; Consultant/advisory: BMS, Merck, Novartis, Roche; Speakers' bureau: Novartis; Research (Inst): Merck KGaA, Novartis, Pfizer; Travel: Amgen, BMS, Merck, Novartis, Roche. D. Cardin: Consulting or advisory role: Merrimack, Raphael Pharmaceuticals; Research funding (Inst.): Celgene, EMD Serono, Hoffman-LaRoche, Incyte, Oncolytics, Synta, BMS, Advaxis (Inst). A. Atasoy: Employment: BMS. R. Postema: BMS employee and shareholder. Z. Boyd: Employment: Bristol Meyers Squibb; Stock and other ownership interests: Roche/Genentech, Bristol Meyers Squibb J-M. Ledeine: Employment: Bristol-Myers Squibb; Stock and other ownership interests: Bristol-Myers Squibb. M. Overman: Consulting or advisory role: Bristol-Myers Squibb, Merrimack, Roche/Genentech; Research funding: Amgen, Bristol-Myers Squibb, Celgene, MedImmune, Merck, Roche. S. Lonardi: Consulting or advisory role: Amgen, Bayer, Merck, Lilly; Speakers' bureau: Lilly, Roche, BMS; Research funding: Amgen. All other authors have declared no conflicts of interest.

FBXW7 functions as a ubiquitin ligase tagging multiple dominant oncogenic proteins and commonly mutates in colorectal cancer. Data suggest missense mutations lead to greater loss of FBXW7 function than other gene aberrations do. However, the clinicopathologic factors and outcomes associated with FBXW7 missense mutations in metastatic colorectal cancer (mCRC) have not been described.Data were obtained from mCRC patients whose tumors were evaluated by next-generation sequencing for hotspot mutations at The University of Texas MD Anderson Cancer Center. Alterations in FBXW7 were identified, and their associations with clinicopathologic features and overall survival (OS) were evaluated.Of 855 mCRC patients, 571 had data on FBXW7 status; 43 (7.5%) had FBXW7 mutations, including 37 with missense mutations. R465C mutations in exon 9 were the most common missense mutations (18.6%). PIK3CA mutations were associated with FBXW7 missense mutations (p=0.012). On univariate analysis, patients with FBXW7 missense mutations had significantly worse OS (median 28.7 mo) than those with wild-type FBXW7 (median 46.6 mo; p=0.003). On multivariate analysis including other known prognostic factors such as BRAF mutations, FBXW7 missense mutations were the strongest negative prognostic factor for OS (hazard ratio 2.0; p=0.003).In the largest clinical dataset of mCRC to date, FBXW7 missense mutations showed a strong negative prognostic association.

MET amplification appears to be a predictive biomarker for MET inhibition. Prior studies reported a MET amplification rate of 9-18% in metastatic colorectal cancer (mCRC) but do not differentiate increased gene copy numbers due to chromosomal level aberrations from focal gene amplifications. Validation of MET amplification rate in mCRC is critical to this field.In tumor tissue-based analyses, overall MET amplification rate was 1.7% (10/590). MET amplification was seen in 0/103 (0%), 4/208 (1.9%) and 6/279 (2.2%) cases, in cohorts 1, 2 and 3, respectively. Rate of MET amplification in cfDNA of cohort 4 patients refractory to anti-EGFR therapy (n = 53) was 22.6% (12/53) and was significantly higher compared to patients not exposed to anti-EGFR therapy (p < 0.001).We analyzed MET amplification in mCRC (n = 795) using different methods across multiple cohorts. Cohort 1 (n = 103) and 2 (n = 208) included resected liver metastases and tumor biopsies, respectively, tested for MET amplification using fluorescence in-situ hybridization [amplification: MET/CEP7 ratio ≥ 2.0]. Using another tissue-based approach, cohort 3 (n = 279) included tumor biopsies sequenced with HiSeq (Illumina) with full exome coverage for MET [amplification: ≥ 4 copies identified by an in-house algorithm]. Using a blood-based approach by contrast, cohort 4 (n = 205) included patients in whom the full exome of MET in circulating-free DNA (cfDNA) was sequenced with HiSeq.Contrary to prior reports, in this large cohort, MET amplification was a rare event in mCRC tissues. In plasma by stark contrast, MET amplification identified by cfDNA occurred in a sizable subset of patients that are refractory to anti-EGFR therapy.

Background RAS mutations are associated with limited overall survival after resection of colorectal liver metastases. Our aim was to determine criteria for considering hepatectomy for patients with RAS mutant colorectal liver metastases. Methods Of 1,163 patients who underwent liver resection for colorectal liver metastases during 2005–2014, all patients operated on with curative intent who had known RAS mutation status were included. Factors associated with overall survival were determined using multivariate analysis. Results A total of 524 patients met the inclusion criteria; 212 (40%) had mutated RAS. Mutations were located on codon 12 in 128 patients (60%) and codon 13 in 29 (14%). At median follow-up of 38 months, median overall survival was 72.6 months for wild-type RAS and 50.9 months for mutated RAS (P < .001). Median overall survival for patients with codon 12 and 13 mutations was 51.9 and 50.9 months, respectively (P = .839), significantly worse than for patients with wild-type RAS (P = .005, and P = .038 for codon 12 and 13, respectively). For patients with RAS mutation, factors associated independently with worse overall survival were node-positive primary tumor, tumor >3 cm, and >7 cycles of preoperative chemotherapy. Major and 2-stage hepatectomy were not associated independently with overall survival. Median overall survival was 57, 41, and 21.5 months for patients with 1, 2, and 3 risk factors, respectively. There were no 4-year survivors in the highest-risk group. Conclusion Patients with multiple risk factors had poor overall survival after curative resection of RAS mutant colorectal liver metastases. For such patients, hepatectomy may be ill advised, and alternative therapies or further systemic therapy should be considered. RAS mutations are associated with limited overall survival after resection of colorectal liver metastases. Our aim was to determine criteria for considering hepatectomy for patients with RAS mutant colorectal liver metastases. Of 1,163 patients who underwent liver resection for colorectal liver metastases during 2005–2014, all patients operated on with curative intent who had known RAS mutation status were included. Factors associated with overall survival were determined using multivariate analysis. A total of 524 patients met the inclusion criteria; 212 (40%) had mutated RAS. Mutations were located on codon 12 in 128 patients (60%) and codon 13 in 29 (14%). At median follow-up of 38 months, median overall survival was 72.6 months for wild-type RAS and 50.9 months for mutated RAS (P < .001). Median overall survival for patients with codon 12 and 13 mutations was 51.9 and 50.9 months, respectively (P = .839), significantly worse than for patients with wild-type RAS (P = .005, and P = .038 for codon 12 and 13, respectively). For patients with RAS mutation, factors associated independently with worse overall survival were node-positive primary tumor, tumor >3 cm, and >7 cycles of preoperative chemotherapy. Major and 2-stage hepatectomy were not associated independently with overall survival. Median overall survival was 57, 41, and 21.5 months for patients with 1, 2, and 3 risk factors, respectively. There were no 4-year survivors in the highest-risk group. Patients with multiple risk factors had poor overall survival after curative resection of RAS mutant colorectal liver metastases. For such patients, hepatectomy may be ill advised, and alternative therapies or further systemic therapy should be considered.

519 Background: Approximately 4% of metastatic colorectal cancers (mCRCs) are associated with high microsatellite instability (MSI-H), indicating a deficient DNA mismatch repair (dMMR) system. dMMR/MSI-H CRC exhibits an increased tumor neoantigen load and immune cell infiltration and is hypothesized to be targetable by immune checkpoint inhibitors. CheckMate 142 (NCT02060188) evaluates the efficacy and safety of nivolumab (nivo) in patients (pts) with dMMR/MSI-H mCRC. Methods: Pts with dMMR/MSI-H mCRC who progressed on/were intolerant to ≥1 prior line of therapy received nivo 3 mg/kg (nivo 3) every 2 weeks (Q2W). The primary endpoint was objective response rate (ORR) per investigator (INV). The secondary endpoint was ORR per independent radiology review committee (IRRC); exploratory endpoints included safety, PFS, OS, and efficacy in biomarker-defined populations. Results: Among pts treated with nivo 3 Q2W (N = 74), 84% had received ≥2 prior lines of therapy. ORRs were 31% (INV) and 27% (IRRC); disease control rates were 69% (INV) and 62% (IRRC). The median time to response was ≈2.7 mo (INV/IRRC). PFS rates at 12 mo were 48.4% (INV) and 45.6% (IRRC). The duration of response and OS medians were not yet reached; OS rates were 83.4% (6 mo) and 73.8% (12 mo). Responses were observed in pts regardless of tumor programmed death-1 ligand 1 (PD-L1) expression level or BRAF or KRAS mutation status and were observed in pts with or without a history of Lynch syndrome (Table). Grade 3–4 treatment-related adverse events (TRAEs) occurred in 20% of pts. TRAEs leading to discontinuation included acute kidney injury, increased ALT, colitis, and stomatitis (1 each). No treatment-related deaths occurred in this arm. Conclusions: Nivo showed durable responses and disease control in heavily pretreated pts with dMMR/MSI-H mCRC. Treatment was well tolerated, with no new safety signals. Clinical trial information: NCT02060188. [Table: see text]

Despite growing therapeutic relevance of ERBB2 amplifications in colorectal cancer (CRC), little is known about ERBB2/ERBB3 mutations. We aimed to characterize these subsets of CRC.We performed a retrospective analysis of 419 CRC patients from MD Anderson (MDACC) and 619 patients from the Nurses' Health Study (NHS)/Health Professionals Follow-Up Study (HPFS) with tissue sequencing, clinicopathologic, mutational, and consensus molecular subtype (CMS) profiles of ERBB2/ERBB3 mutant patients. A third cohort of 1623 CRC patients with ctDNA assays characterized the ctDNA profile of ERBB2 mutants. All statistical tests were two-sided.ERBB2 mutations occurred in 4.1% (95% confidence interval [CI] = 2.4% to 6.4%), 5.8% (95% CI = 4.1% to 8.0%), and 5.1% (95% CI = 4.0% to 6.2%) of MDACC, NHS/HPFS, and ctDNA patients, respectively. ERBB3 mutations occurred in 5.7% (95% CI = 3.7% to 8.4%, 95% CI = 4.0% to 7.8%) of patients in both tissue cohorts. Age, stage, and tumor location were not associated with either mutation. Microsatellite instability (MSI) was associated with ERBB2 (odds ratio [OR] = 5.98, 95% CI = 2.47 to 14.49, P < .001; OR = 5.13, 95% CI = 2.38 to 11.05, P < .001) and ERBB3 mutations (OR = 3.48, 95% CI = 1.51 to 8.02, P = .002; OR = 3.40, 95% CI = 1.05 to 10.96, P = .03) in both tissue cohorts. Neither gene was associated with TP53, APC, KRAS, NRAS, or BRAF mutations in tissue. However, PIK3CA mutations were strongly associated with ERBB2 mutations in all three cohorts (OR = 3.68, 95% CI = 1.83 to 7.41, P = .001; OR = 2.25, 95% CI = 1.11 to 4.58, P = .02; OR = 2.11, 95% CI = 1.25 to 3.58, P = .004) and ERBB3 mutations in the MDACC cohort (OR = 13.26, 95% CI = 5.27 to 33.33, P < .001). ERBB2 (P = 0.08) and ERBB3 (P = .008) mutations were associated with CMS1 subtype. ERBB2 (hazard ratio [HR] = 1.82, 95% CI = 1.23 to 4.03, P = .009), but not ERBB3 (HR = 0.88, 95% CI = 0.45 to 1.73, P = .73), mutations were associated with worse overall survival.MSI and PIK3CA mutations are associated with ERBB2/ERBB3 mutations. Co-occurring PIK3CA mutations may represent a second hit to oncogenic signaling that needs consideration when targeting ERBB2/ERBB3.

This review seeks to provide an informed prospective on the advances in molecular profiling and analysis of colorectal cancer (CRC). The goal is to provide a historical context and current summary on how advances in gene and protein sequencing technology along with computer capabilities led to our current bioinformatic advances in the field.An explosion of knowledge has occurred regarding genetic, epigenetic, and biochemical alterations associated with the evolution of colorectal cancer. This has led to the realization that CRC is a heterogeneous disease with molecular alterations often dictating natural history, response to treatment, and outcome. The consensus molecular subtypes (CMS) classification classifies CRC into four molecular subtypes with distinct biological characteristics, which may form the basis for clinical stratification and subtype-based targeted intervention. This review summarizes new developments of a field moving "Back to the Future." CRC molecular subtyping will better identify key subtype specific therapeutic targets and responses to therapy.

11 Background: In the phase 2 CheckMate 142 trial, nivolumab plus low-dose ipilimumab provided robust and durable clinical benefit and was well tolerated as first-line therapy for microsatellite instability-high/DNA mismatch repair deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC) (Lenz et al. Ann Oncol 2018;29:LBA18). Longer follow-up data will be presented. Methods: Patients with MSI-H/dMMR mCRC and no prior treatment for metastatic disease received nivolumab 3 mg/kg every 2 weeks plus low-dose ipilimumab 1 mg/kg every 6 weeks until disease progression or discontinuation. The primary endpoint was investigator-assessed objective response rate (ORR). Results: For all 45 patients (median follow-up was 13.8 months), ORR was 60% (95% CI 44.3–74.3). Responses were consistent with the overall population across subgroups including age, Eastern Cooperative Oncology Group (ECOG) performance status, prior adjuvant/neoadjuvant therapy, and mutation status (Table). Seven patients (16%) had grade 3–4 treatment-related adverse events; 3 (7%) had any grade treatment-related adverse events leading to discontinuation. Updated response, survival, and safety data after a longer follow-up (median 19.9 months) will be presented. Conclusions: Nivolumab plus low-dose ipilimumab demonstrated robust and durable clinical benefit and was well tolerated. Evaluated subgroups had responses consistent with the overall population. Nivolumab plus low-dose ipilimumab may represent a new first-line treatment option for patients with MSI-H/dMMR mCRC. Clinical trial information: NCT02060188. [Table: see text]

Small bowel adenocarcinoma (SBA) is a rare cancer that has been treated similarly to colorectal cancer (CRC) in the advanced setting. Incidence has been increasing as detection efforts have been improving for these challenging-to-diagnose tumors, but patients frequently experience prolonged nonspecific symptoms due to delayed diagnosis. As a result of such delays and likely due to variant biology, patient outcomes for SBA are inferior to those for CRC at all stages of diagnosis. Recent molecular studies highlight the genomic differences underpinning these tumors and suggest new future pathways for treatment, distinct from CRC.

Malignant peritoneal mesothelioma (MPeM) is a rare but aggressive malignancy with limited treatment options. VEGF inhibition enhances efficacy of immune-checkpoint inhibitors by reworking the immunosuppressive tumor milieu. Efficacy and safety of combined PD-L1 (atezolizumab) and VEGF (bevacizumab) blockade (AtezoBev) was assessed in 20 patients with advanced and unresectable MPeM with progression or intolerance to prior platinum-pemetrexed chemotherapy. The primary endpoint of confirmed objective response rate per RECISTv1.1 by independent radiology review was 40% [8/20; 95% confidence interval (CI), 19.1-64.0] with median response duration of 12.8 months. Six (75%) responses lasted for >10 months. Progression-free and overall survival at one year were 61% (95% CI, 35-80) and 85% (95% CI, 60-95), respectively. Responses occurred notwithstanding low tumor mutation burden and PD-L1 expression status. Baseline epithelial-mesenchymal transition gene expression correlated with therapeutic resistance/response (r = 0.80; P = 0.0010). AtezoBev showed promising and durable efficacy in patients with advanced MPeM with an acceptable safety profile, and these results address a grave unmet need for this orphan disease. SIGNIFICANCE: Efficacy of atezolizumab and bevacizumab vis-à-vis response rates and survival in advanced peritoneal mesothelioma previously treated with chemotherapy surpassed outcomes expected with conventional therapies. Biomarker analyses uncovered epithelial-mesenchymal transition phenotype as an important resistance mechanism and showcase the value and feasibility of performing translationally driven clinical trials in rare tumors.See related commentary by Aldea et al., p. 2674.This article is highlighted in the In This Issue feature, p. 2659.

Recent studies defined a potentially important role of the microbiome in modulating pancreatic ductal adenocarcinoma (PDAC) and responses to therapies. We hypothesized that antibiotic usage may predict outcomes in patients with PDAC. We retrospectively analyzed clinical data of patients with resectable or metastatic PDAC seen at MD Anderson Cancer from 2003 to 2017. Demographic, chemotherapy regimen and antibiotic use, duration, type, and reason for indication were recorded. A total of 580 patients with PDAC were studied, 342 resected and 238 metastatic patients, selected retrospectively from our database. Antibiotic use, for longer than 48 hrs, was detected in 209 resected patients (61%) and 195 metastatic ones (62%). On resectable patients, we did not find differences in overall survival (OS) or progression-free survival (PFS), based on antibiotic intake. However, in the metastatic cohort, antibiotic consumption was associated with a significantly longer OS (13.3 months vs. 9.0 months, HR 0.48, 95% CI 0.34-0.7, p = 0.0001) and PFS (4.4 months vs. 2 months, HR 0.48, 95% CI 0.34-0.68, p = <0.0001). In multivariate analysis, the impact of ATB remained significant for PFS (HR 0.59, p = 0.005) and borderline statistically significant for OS (HR 0.69, p = 0.06). When we analyzed by chemotherapy regimen, we found that patients who received gemcitabine-based chemotherapy as first-line therapy (n = 118) had significantly prolonged OS (HR 0.4, p 0.0013) and PFS (HR 0.55, p 0.02) if they received antibiotics, while those receiving 5FU-based chemotherapy (n = 98) had only prolonged PFS (HR 0.54, p = 0.03). Antibiotics-associated modulation of the microbiome is associated with better outcomes in patients with metastatic PDAC.

Small-bowel adenocarcinoma (SBA) is rare, and no standard of care exists for metastatic disease beyond first-line FOLFOX/CAPOX. SBA has higher rates of microsatellite instability (MSI-H) and T-lymphocyte infiltration than other gastrointestinal cancers. We hypothesize that pembrolizumab, a PD-1 inhibitor, will induce antitumor response.Patients with previously treated advanced SBA received pembrolizumab 200 mg i.v. every 3 weeks until disease progression (PD), toxicity, or 35 doses maximum. Primary endpoint was confirmed overall response rate (ORR) with secondary progression-free survival (PFS), overall survival (OS), and toxicity assessment endpoints. Outcomes were stratified by tumor location, microsatellite stability (MSS) or instability (MSI-H), and PD-L1 level.Forty patients were treated for a median duration of four cycles (range, 1-35). All patients are off study treatment due to PD (75%), death (10%), 35 cycles completed (8%), refusal (3%), and adverse effects (AEs, 5%). Three confirmed partial responses [PRs; 8%; 95% confidence interval (CI), 2-20] did not meet predefined success criteria of ORR 30%. Median OS (7.1 months; 95% CI, 5.1-17.1) and median PFS (2.8 months; 95% CI, 2.7-4.2) were similar across primary tumor sites. One confirmed PR (3%) was seen in patients with low MSS/MSI tumors and correlated with high tumor mutation burden (TMB). Fifty percent of patients with MSI-H tumors achieved PR and remain alive without progression. Twenty-five patients (63%) had grade ≥3 AEs and 11 patients (28%) had grade 4/5 AEs.In the largest study of SBA to date, pembrolizumab did not induce the hypothesized response rate; however, we did identify responses in key biomarker-selected cohorts.

AT-rich interactive domain 1A (ARID1A) is commonly mutated in colorectal cancer, frequently resulting in truncation and loss of protein expression. ARID1A recruits MSH2 for mismatch repair during DNA replication. ARID1A deficiency promotes hypermutability and immune activation in preclinical models, but its role in patients with colorectal cancer is being explored.The DNA sequencing and gene expression profiling of patients with colorectal cancer were extracted from The Cancer Genome Atlas and MD Anderson Cancer Center databases, with validation utilizing external databases, and correlation between ARID1A and immunologic features. IHC for T-cell markers was performed on a separate cohort of patients.Twenty-eight of 417 patients with microsatellite stable (MSS) colorectal cancer (6.7%) had ARID1A mutation. Among 58 genes most commonly mutated in colorectal cancer, ARID1A mutation had the highest increase with frameshift mutation rates in MSS cases (8-fold, P < 0.001). In MSS, ARID1A mutation was enriched in immune subtype (CMS1) and had a strong correlation with IFNγ expression (Δz score +1.91, P < 0.001). Compared with ARID1A wild-type, statistically significant higher expression for key checkpoint genes (e.g., PD-L1, CTLA4, and PDCD1) and gene sets (e.g., antigen presentation, cytotoxic T-cell function, and immune checkpoints) was observed in mutant cases. This was validated by unsupervised differential expression of genes related to immune response and further confirmed by higher infiltration of T cells in IHC of tumors with ARID1A mutation (P = 0.01).The immunogenicity of ARID1A-mutant cases is likely due to an increased level of neoantigens resulting from increased tumor mutational burden and frameshift mutations. Tumors with ARID1A mutation may be more susceptible to immune therapy-based treatment strategies and should be recognized as a unique molecular subgroup in future immune therapy trials.

9047 Background: Upregulation of CD73 in multiple cancers increases adenosine production, leading to local immunosuppression. Oleclumab, a human IgG1λ mAb, inhibits CD73 function and may increase antitumor immunity. Initial data from a Phase I, first-in-human, dose-escalation and expansion study showed that oleclumab ± durvalumab had manageable safety and encouraging clinical activity in pts with advanced CRC or PDAC. We report updated safety and activity in these cohorts and the first results in an expansion cohort of pts with advanced EGFRm NSCLC. Methods: Previously treated pts with histologically or cytologically confirmed microsatellite stable CRC, PDAC, or EGFRm NSCLC received oleclumab 5–40 mg/kg (escalation) and 40 mg/kg (expansion) IV Q2W, alone (escalation only) or with durvalumab 10 mg/kg IV Q2W. The primary objective was safety; secondary efficacy objectives included objective response (OR) per RECIST v1.1 and duration of response (DoR). Results: 66 pts were enrolled in the escalation phase (35 CRC, 31 PDAC) and 126 in the expansion phase (42 CRC, 42 PDAC, 42 EGFRm NSCLC). At data cutoff (DCO; June 9, 2020), the median number of oleclumab doses was 4 in pts on monotherapy (range 1–26) and 4 in pts on combination therapy across both phases (range 1–76). In the escalation phase, there were no DLTs in pts on monotherapy or combination therapy; treatment-related adverse events (TRAEs) occurred in 54.8% of pts on monotherapy (Grade 3–4 in 7.1%) and 54.2% of pts on combination therapy (Grade 3–4 in 20.8%); fatigue was the most common TRAE with both regimens. No TRAEs resulted in death. In previous interim analyses before this DCO, no ORs were reported in the escalation phase. In the expansion phase, 5 pts were treated for ≥12 mos; 6 pts were ongoing at DCO. TRAEs occurred in 54.0% (Grade 3–5 in 15.1%); the most common TRAEs were fatigue (15.1%), diarrhea (9.5%), and rash (7.1%). One pt had a TRAE resulting in death (systemic inflammatory response syndrome). ORs were seen in 1 CRC pt (DoR 35.9+ mos [+ = ongoing response]), 2 PDAC pts (DoR 22.1+ and 28.6+ mos), and 4 EGFRm NSCLC pts (DoR range 5.6 to 15.7+ mos, median not reached; only 1 of the 4 pts had ≥25% programmed cell death ligand-1 [PD-L1]+ tumor cells). Nine CRC pts, 8 PDAC pts, and 9 EGFRm NSCLC pts had SD. Of 6 pts with matched biopsies who received combination therapy, 5 had increases in CD8+ T cells, PD-L1, and granzyme B. Baseline tumor CD73 expression and association with clinical response will be presented. Conclusions: Oleclumab ± durvalumab had a tolerable safety profile and combination therapy showed promising antitumor activity in EGFRm NSCLC. ORs and SD were durable, even in tumor types that are generally immunotherapy-resistant. Clinical trial information: NCT02503774.