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The original version of this article contained an error in Figure 1a. The number of patients at risk listed in the Veliparib arm of Figure 1a should have read “65” instead of “35”. An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Over the last 10 years, crucial improvements have been made in the pursuit of more effective therapies for colorectal cancer (CRC). In understanding the basis of CRC biology we have evolved from the classical ‘adenoma to carcinoma transition’ hypothesis, to the identification of two CRC clusters (microsatellite instability and chromosomal instability) and further classifications based on epigenetic events. Thanks to these advances in molecular analyses, key pathways, notably that of the EGFR, are now integrated into standard practice for therapeutic management and other pathways are being explored for blocking driving mutations and overcoming drug resistance. Genetic profiling is being developed to better predict prognosis and treatment response. The CRC subtyping consortium has combined and reanalyzed genetic signature data sets from several international groups. A definitive genetic CRC classification is currently being established and will be critical for clinical development of therapeutic strategies.

Metastasis is respoMetastasis is responsible for most cancer-related deaths, and, among common tumor types, melanoma is one with great potential to metastasize. Here we study the contribution of epigenetic changes to the dissemination process by analyzing the changes that occur at the DNA methylation level between primary cancer cells and metastases. We found a hypomethylation event that reactivates a cryptic transcript of the Rab GTPase activating protein TBC1D16 (TBC1D16-47 kDa; referred to hereafter as TBC1D16-47KD) to be a characteristic feature of the metastatic cascade. This short isoform of TBC1D16 exacerbates melanoma growth and metastasis both in vitro and in vivo. By combining immunoprecipitation and mass spectrometry, we identified RAB5C as a new TBC1D16 target and showed that it regulates EGFR in melanoma cells. We also found that epigenetic reactivation of TBC1D16-47KD is associated with poor clinical outcome in melanoma, while conferring greater sensitivity to BRAF and MEK inhibitors.

Importance The histiocytic neoplasms Erdheim-Chester disease (ECD) and Langerhans cell histiocytosis (LCH) are highly enriched forBRAFV600 mutations and have been previously shown to be responsive to treatment with vemurafenib, an inhibitor of the BRAF V600 kinase. However, the long-term efficacy and safety of prolonged vemurafenib use in these patients are not defined. Here we analyze the final efficacy and safety data for vemurafenib in patients with ECD and LCH enrolled in the VE-BASKET study. Objective To determine the efficacy and safety of vemurafenib in adults with ECD or LCH enrolled in the VE-BASKET study. Design, Setting, and Participants The VE-BASKET study was an open-label, nonrandomized, multicohort study for patients with nonmelanoma cancers harboring theBRAFV600 mutation. Patients withBRAFV600–mutant ECD or LCH were enrolled in an “other solid tumor” cohort of the VE-BASKET study, and they were enrolled in the present study. Interventions Patients received vemurafenib, 960 mg, twice daily continuously until disease progression, study withdrawal, or occurrence of intolerable adverse effects. Main Outcomes and Measures The primary end point was confirmed objective response rate (ORR) by Response Evaluation Criteria in Solid Tumors (RECIST, version 1.1). Secondary end points included progression-free survival (PFS), overall survival (OS), metabolic response by modified positron-emission tomography (PET) Response Criteria in Solid Tumors (PERCIST) using18F-fluorodeoxyglucose (FDG)-PET/computed tomography (CT), and safety. Results A total of 26 patients from the VE-BASKET trial (22 with ECD, 4 with LCH) were included in the present study (14 women and 12 men; median age, 61 years; age range, 51-74 years). The confirmed ORR was 61.5% (95% CI, 40.6%-79.8%) in the overall cohort and 54.5% (95% CI, 32.2%-75.6%) in patients with ECD. All evaluable patients achieved stable disease or better. The median PFS and OS had not been reached in the overall cohort at study closure despite a median follow-up of 28.8 months; 2-year PFS was 86% (95% CI, 72%-100%), and 2-year OS was 96% (95% CI, 87%-100%). All 15 patients evaluated by FDG-PET/CT achieved a metabolic response, including 12 patients (80%) with a complete metabolic response. The most common adverse events (AEs) in the overall cohort included arthralgia, maculopapular rash, fatigue, alopecia, prolonged QT interval, skin papilloma, and hyperkeratosis. Hypertension and dermatologic AEs occurred at higher rates than those reported in metastatic melanoma. Conclusions and Relevance In this study, vemurafenib had prolonged efficacy in patients withBRAFV600–mutant ECD and LCH and warrants consideration as a new standard of care for these patients.

Purpose The safety and efficacy of pembrolizumab, a humanized monoclonal antibody against programmed death 1 (PD-1), were assessed in patients with programmed death ligand 1 (PD-L1)–expressing extensive-stage small-cell lung cancer (SCLC) in the multicohort, phase Ib open-label KEYNOTE-028 study ( ClinicalTrials.gov identifier: NCT02054806). Methods Patients with SCLC received pembrolizumab 10 mg/kg every 2 weeks for 24 months or until disease progression or intolerable toxicity occurred. PD-L1 expression was assessed by immunohistochemistry. PD-L1–positive patients had membranous PD-L1 expression in ≥ 1% of tumor and associated inflammatory cells or positive staining in stroma. Response was assessed by investigator per Response Evaluation Criteria in Solid Tumors version 1.1 every 8 weeks for the first 6 months and every 12 weeks thereafter. Adverse events (AEs) were reported per the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0. Primary end points were safety, tolerability, and objective response rate (ORR). Secondary end points included progression-free survival, overall survival, and duration of response. Results Twenty-four patients with PD-L1–expressing SCLC were enrolled and received at least one pembrolizumab dose. At the data cutoff date (June 20, 2016), the median follow-up duration was 9.8 months (range, 0.5 to 24 months). All 24 patients experienced AEs; the most common were asthenia (n = 7), fatigue (n = 7), and cough (n = 6). Two patients experienced grade 3 to 5 treatment-related AEs: one patient had elevated bilirubin, and one patient had asthenia, grade 5 colitis, and intestinal ischemia. One patient had a complete response, and seven patients had partial responses, resulting in an ORR of 33% (95% CI, 16% to 55%). Conclusion The safety of pembrolizumab was consistent with the known safety profile in other tumor types. Pembrolizumab demonstrated promising antitumor activity in patients with pretreated, PD-L1–expressing SCLC.

Background Colorectal cancers (CRCs) expressing programmed death ligand 1 (PD-L1) have poor prognosis. In the multicohort KEYNOTE-028 trial, the anti-PD-1 antibody pembrolizumab was evaluated in 20 PD-L1-positive advanced solid tumors. Herein, we report results for the advanced CRC cohort. Methods Patients with advanced, treatment-resistant PD-L1-positive carcinoma of the colon or rectum were enrolled, regardless of microsatellite instability (MSI) status. Pembrolizumab 10 mg/kg was administered every 2 weeks for up to 2 years or until disease progression/unacceptable toxicity. Response was assessed every 8 weeks for the first 6 months and every 12 weeks thereafter. Primary end points were safety and overall response rate by investigator review per Response Evaluation Criteria in Solid Tumors version 1.1. Data cutoff was June 20, 2016. Results Of 137 patients with CRC and samples evaluable for PD-L1 expression, 33 (24%) had PD-L1-positive tumors, of which 23 were enrolled. Median follow-up was 5.3 months, and 8 patients (35%) reported treatment-related adverse events (AEs), most commonly fatigue (n = 3, 13%), stomatitis (n = 2, 9%), and asthenia (n = 2, 9%). One patient (4%) experienced grade 4 treatment-related increased blood bilirubin. No grade 3 AEs, discontinuations, or deaths were attributed to treatment. Most patients (n = 15, 65%) experienced progressive disease. One partial response occurred in a patient (4%) with MSI-high CRC. Conclusion Pembrolizumab demonstrated a favorable safety profile in advanced PD-L1-positive CRC. Antitumor activity was observed in a single patient with MSI-high CRC, warranting further evaluation in this patient population. (Clinicaltrials.gov registration: NCT02054806).

In metastatic colorectal cancer (mCRC), recent studies have shown the importance to accurately quantify low-abundance mutations of the RAS pathway because anti-EGFR therapy may depend on certain mutation thresholds. We aimed to evaluate the added predictive value of an extended RAS panel testing using two commercial assays and a highly sensitive and quantitative digital PCR (dPCR). Tumor samples from 583 mCRC patients treated with anti–EGFR- (n = 255) or bevacizumab- (n = 328) based therapies from several clinical trials and retrospective series from the TTD/RTICC Spanish network were analyzed by cobas, therascreen, and dPCR. We evaluated concordance between techniques using the Cohen kappa index. Response rate, progression-free survival (PFS), and overall survival (OS) were correlated to the mutational status and the mutant allele fraction (MAF). Concordance between techniques was high when analyzing RAS and BRAF (Cohen kappa index around 0.75). We observed an inverse correlation between MAF and response in the anti-EGFR cohort (P < 0.001). Likelihood ratio analysis showed that a fraction of 1% or higher of any mutated alleles offered the best predictive value. PFS and OS were significantly longer in RAS/BRAF wild-type patients, independently of the technique. However, the predictability of both PFS and OS were higher when we considered a threshold of 1% in the RAS scenario (HR = 1.53; CI 95%, 1.12–2.09 for PFS, and HR = 1.9; CI 95%, 1.33–2.72 for OS). Although the rate of mutations observed among techniques is different, RAS and BRAF mutational analysis improved prediction of response to anti-EGFR therapy. Additionally, dPCR with a threshold of 1% outperformed the other platforms. Mol Cancer Ther; 16(9); 1999–2007. ©2017 AACR.

Colorectal cancer; Driver gene; Mutant allele fraction Càncer colorectal; Gen conductor; Fracció d'al·lel mutant Cáncer colorrectal; Gen conductor; Fracción de alelo mutante Sequencing of tumors is now routine and guides personalized cancer therapy. Mutant allele fractions (MAFs, or the 'mutation dose') of a driver gene may reveal the genomic structure of tumors and influence response to targeted therapies. We performed a comprehensive analysis of MAFs of driver alterations in unpaired primary and metastatic colorectal cancer (CRC) at our institution from 2010 to 2015 and studied their potential clinical relevance. Of 763 CRC samples, 622 had detailed annotation on overall survival in the metastatic setting (OSmet) and 89 received targeted agents matched to KRAS (MEK inhibitors), BRAF (BRAF inhibitors), or PIK3CA mutations (PI3K pathway inhibitors). MAFs of each variant were normalized for tumor purity in the sample (adjMAFs). We found lower adjMAFs for BRAFV600E and PIK3CA than for KRAS, NRAS, and BRAF non-V600 variants. TP53 and BRAFV600E adjMAFs were higher in metastases as compared to primary tumors, and high KRAS adjMAFs were found in CRC metastases of patients with KRAS wild-type primary tumors previously exposed to EGFR antibodies. Patients with RAS- or BRAFV600E -mutated tumors, irrespective of adjMAFs, had worse OSmet. There was no significant association between adjMAFs and time to progression on targeted therapies matched to KRAS, BRAF, or PIK3CA mutations, potentially related to the limited antitumor activity of the employed drugs (overall response rate of 4.5%). In conclusion, the lower BRAFV600E and PIK3CA adjMAFs in subsets of primary CRC tumors indicate subclonality of these driver genes. Differences in adjMAFs between metastases and primary tumors suggest that approved therapies may result in selection of BRAFV600E - and KRAS-resistant clones and an increase in genomic heterogeneity with acquired TP53 alterations. Despite significant differences in prognosis according to mutations in driver oncogenes, adjMAFs levels did not impact on survival and did not help predict benefit with matched targeted agents in the metastatic setting.

Preclinical evidence suggests that concomitant BRAF and EGFR inhibition leads to sustained suppression of MAPK signaling and suppressed tumor growth in BRAF V600E colorectal cancer (CRC) models. Patients with refractory BRAF V600–mutant metastatic CRC (mCRC) were treated with a selective RAF kinase inhibitor (encorafenib) plus a monoclonal antibody targeting EGFR (cetuximab), with (n = 28) or without (n = 26) a PI3K-alpha inhibitor (alpelisib). The primary objective was to determine the maximum tolerated dose (MTD) or a recommended phase 2 dose. Dose-limiting toxicities were reported in three patients receiving dual- and two patients receiving triple-treatment. The MTD was not reached for either group and the Phase 2 doses were selected as 200 mg encorafenib (both groups) and 300 mg alpelisib. Combinations of cetuximab and encorafenib show promising clinical activity and tolerability in patients with BRAF-mutant mCRC; confirmed overall response rates of 19% and 18% were observed, and median progression-free survival was 3.7 and 4.2 months, for the dual- and triple-therapy groups, respectively.

In metastatic colorectal cancer (mCRC), recent studies have shown the importance to accurately quantify low-abundance mutations of the

The MAPK cascade plays a crucial role in tumor cell proliferation and survival. Accumulating evidence suggests that mutations in the BRAF oncogene are not only associated with poor prognosis but also linked with less benefit when treated with anti-epidermal growth factor receptor antibodies in metastatic colorectal cancer (mCRC). Targeting this molecular aberration has thus become a matter of particular interest in mCRC drug development. In contrast to other malignances such as BRAF mutant melanoma, efficacy observed with BRAF inhibitors in monotherapy in mCRC is poor. Several mechanisms of resistance have been identified leading to the development of different treatment strategies that have shown promising activity in early clinical trials. Hence, rational combination of targeted therapies is expected to further increase the efficacy of selective BRAF inhibitors. Herein, we discuss the main clinical and molecular characteristics of BRAF mutant colorectal cancer and its translation into the clinic, with a focus on developmental therapeutics and combination strategies. In addition, we contextualize the available data with potential future approaches that include the extended access to next-generation sequencing platforms and gene expression strategies for molecular subtyping. These approaches will facilitate the identification of certain patient profiles providing more therapeutic possibilities.

Purpose: Lurbinectedin (PM01183) binds covalently to DNA and has broad activity against tumor cell lines. This first-in-human phase I study evaluated dose-limiting toxicities (DLT) and defined a phase II recommended dose for PM01183 as a 1-hour intravenous infusion every three weeks (q3wk). Experimental Design: Thirty-one patients with advanced solid tumors received escalating doses of PM01183 following an accelerated titration design. Results: PM01183 was safely escalated over 200-fold, from 0.02 to 5.0 mg/m2. Dose doubling was utilized, requiring 15 patients and nine dose levels to identify DLT. The recommended dose was 4.0 mg/m2, with one of 15 patients having DLT (grade 4 thrombocytopenia). Clearance was independent of body surface area; thus, a flat dose of 7.0 mg was used during expansion. Myelosuppression, mostly grade 4 neutropenia, occurred in 40% of patients but was transient and manageable, and none was febrile. All other toxicity was mild and fatigue, nausea and vomiting were the most common at the recommended dose. Pharmacokinetic parameters showed high interindividual variation, though linearity was observed. At or above the recommended dose, the myelosuppressive effect was significantly associated with the area under the concentration-time curve from time zero to infinity (white blood cells, P = 0.0007; absolute neutrophil count, P = 0.016). A partial response was observed in one patient with pancreatic adenocarcinoma at the recommended dose. Conclusion: A flat dose of 7.0 mg is the recommended dose for PM01183 as a 1-hour infusion q3wk. This dose is tolerated and active. Severe neutropenia occurred at this dose, although it was transient and with no clinical consequences in this study. Clin Cancer Res; 20(8); 2205–14. ©2014 AACR.

Purpose: This phase I/II study evaluated safety, efficacy, and pharmacokinetics of escalating, multiple doses of siltuximab, a chimeric anti-interleukin (IL)-6 monoclonal antibody derived from a new Chinese hamster ovary (CHO) cell line in patients with advanced/refractory solid tumors. Experimental Design: In the phase I dose-escalation cohorts, 20 patients with advanced/refractory solid tumors received siltuximab 2.8 or 5.5 mg/kg every 2 weeks or 11 or 15 mg/kg every 3 weeks intravenously (i.v.). In the phase I expansion (n = 24) and phase II cohorts (n = 40), patients with Kirsten rat sarcoma-2 (KRAS)-mutant tumors, ovarian, pancreatic, or anti-EGF receptor (EGFR) refractory/resistant non–small cell lung cancer (NSCLC), colorectal, or H&N cancer received 15 mg/kg every 3 weeks. The phase II primary efficacy endpoint was complete response, partial response, or stable disease >6 weeks. Results: Eighty-four patients (35 colorectal, 29 ovarian, 9 pancreatic, and 11 other) received a median of three (range, 1–45) cycles. One dose-limiting toxicity occurred at 5.5 mg/kg. Common grade ≥3 adverse events were hepatic function abnormalities (15%), physical health deterioration (12%), and fatigue (11%). Ten percent of patients had siltuximab-related grade ≥3 adverse events. Neutropenia (4%) was the only possibly related adverse event grade ≥3 reported in >1 patient. Serious adverse events were reported in 42%; most were related to underlying disease. The pharmacokinetic profile of CHO-derived siltuximab appears similar to the previous cell line. No objective responses occurred; 5 of 84 patients had stable disease >6 weeks. Hemoglobin increased ≥1.5 g/dL in 33 of 47 patients. At 11 and 15 mg/kg, completely sustained C-reactive protein suppression was observed. Conclusions: Siltuximab monotherapy appears to be well tolerated but without clinical activity in solid tumors, including ovarian and KRAS-mutant cancers. The recommended phase II doses were 11 and 15 mg/kg every 3 weeks. Clin Cancer Res; 20(8); 2192–204. ©2014 AACR.

Although colorectal cancer was one of the first solid tumors to be characterized at the molecular level, a consensus biological classification for researchers and clinicians is lacking. Prognosis and therapy are mainly defined on the basis of patient characteristics and histopathological findings, despite studies showing that, according to mutation and gene-expression profiles, the evolution of colorectal cancer differs substantially, probably because of the high heterogeneity of the disease. In this paper we review the original molecular classifications of colorectal cancer, microsatellite and chromosomal unstable tumors, and more recent attempts to characterize the disease by using intrinsic gene expression clustering methods. These have identified at least three subtypes with different hypermutation, proliferation, and epithelial and mesenchymal features. Furthermore, we discuss preliminary data from evaluation of the potential effect of colorectal cancer subtype on prognosis and treatment response.

Bacteria go the distance in cancer The bacterial species Fusobacterium nucleatum is associated with a subset of human colorectal cancers, but its role in tumorigenesis is unclear. Studying patient samples, Bullman et al. found that F. nucleatum and certain co-occurring bacteria were present not only in primary tumors but also in distant metastases. Preliminary evidence suggests that the bacterium is localized primarily within the metastatic cancer cells rather than in the stroma. Antibiotic treatment of mice carrying xenografts of F. nucleatum –positive human colorectal cancer slowed tumor growth, consistent with a causal role for the bacterium in tumorigenesis. Science , this issue p. 1443

Background There are currently no good indicators of which patients with cancer will respond or not to immunotherapy. Novel computational analysis of computed tomography scans (CT) (i.e. radiomics) provides information about the tumour-infiltrating CD8 and predict response to immunotherapy. We aim to validate in an external cohort the VHIO CT-radiomics signature and to develop a combined radiomics-clinical signature that predicts the response to immune checkpoint inhibitors in patients with advanced solid tumours. Methods The VHIO CT-radiomics signature was developed in a population of 115 consecutive patients treated with immune checkpoint inhibitors (programmed-death protein 1 [PD-1] or programmed-death ligand 1 [PD-L1] inhibitors) monotherapy in phase I clinical trials (Cohort 1). The external validation included 62 consecutive patients with urinary bladder cancer treated with anti-PD-1 or PD-L1 monotherapy (Cohort 2). From the baseline CT, a target lesion per patient was delineated. Radiomics variables of first-order, shape, and texture were extracted. An elastic-net model combining radiomics and clinical features was implemented. The association between the radiomics score and changes in tumour shrinkage was assessed using Mann-Whitney analysis. Results In the Cohort 1 the CT-radiomics signature associates with response (area under the curve [AUC] of 0.81, p-value=2.74x10-5 and 0.72, p = 0.001 in the training and internal validation sets, respectively). In the external validation set (Cohort 2), the CT-radiomics signature predicts a response with an AUC of and 0.76 (p = 0.001). The model combining radiomics and clinical features has an AUC of 0.84 (p-value=5.04x10-9) for response prediction. Tumour homogeneity, hypodensity and spherical shape together with high lymphocytes and albumin and low neutrophils, corresponding to a high clinical-radiomics signature score, are indicators of tumour response. A higher CT-radiomics signature score is associated with a larger tumour shrinkage (p Conclusions CT-radiomics signature at baseline predicts the response to immune checkpoint inhibitors. Integrating radiomics and clinical data improved the response prediction capacity. Legal entity responsible for the study The authors. Funding This study was supported by the Banco Bilbao Vizcaya Argentaria and Fundacio La Caixa. RPL is supported by a Prostate Cancer Foundation Young Investigator award. Disclosure J. Martin Liberal: Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Roche; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Novartis; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: MSD; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Pfizer; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Ipsen; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Pierre Fabre; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Astellas; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Bristol-Myers Squibb. R. Morales Barrera: Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Sanofi Aventis; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Bayer; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Janssen; Advisory / Consultancy, Speaker Bureau / Expert testimony: AstraZeneca; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Merck Sharp & Dohme; Advisory / Consultancy, Speaker Bureau / Expert testimony: Asofarm; Travel / Accommodation / Expenses: Roche; Travel / Accommodation / Expenses: Astellas; Travel / Accommodation / Expenses: Pharmacyclics; Travel / Accommodation / Expenses: Clovis Oncology; Travel / Accommodation / Expenses: Lilly. E. Elez: Travel / Accommodation / Expenses: Merck; Travel / Accommodation / Expenses: Sanofi; Travel / Accommodation / Expenses: Roche; Travel / Accommodation / Expenses: Servier and Amge ; Research grant / Funding (self): Merck. E. Felip: Honoraria (self): AbbVie; Honoraria (self): AstraZeneca; Honoraria (self): Blue Print Medicines; Honoraria (self): Boehringer Ingelheim; Honoraria (self): Bristol-Myers Squibb; Honoraria (self): Celgene; Honoraria (self): Eli Lilly; Honoraria (self): Guardant Health; Honoraria (self): Janssen; Honoraria (self): Medscape; Honoraria (self): Merck KGaA; Honoraria (self): MSD; Honoraria (self): Novartis; Honoraria (self): Pfizer; Honoraria (self): Takeda; Honoraria (self): Touchtime. J. Tabernero: Advisory / Consultancy: Array Biopharma; Advisory / Consultancy: AstraZeneca; Advisory / Consultancy: Bayer; Advisory / Consultancy: BeiGene; Advisory / Consultancy: Boehringer Ingelheim; Advisory / Consultancy: Chugai; Advisory / Consultancy: Genentech, Inc; Advisory / Consultancy: Genmab A/S; Advisory / Consultancy: Halozyme; Advisory / Consultancy: Imugene Limited; Advisory / Consultancy: Inflection Biosciences Limited; Advisory / Consultancy: Ipsen; Advisory / Consultancy: Kura Oncology; Advisory / Consultancy: Lilly; Advisory / Consultancy: MSD; Advisory / Consultancy: Menarini; Advisory / Consultancy: Merck Serono; Advisory / Consultancy: Merus; Advisory / Consultancy: Molecular Partners; Advisory / Consultancy: Novartis; Advisory / Consultancy: Peptomyc; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Pharmacyclics; Advisory / Consultancy: ProteoDesign SL; Advisory / Consultancy: F. Hoffmann-La Roche Ltd; Advisory / Consultancy: Sanofi; Advisory / Consultancy: SeaGen; Advisory / Consultancy: Seattle Genetics; Advisory / Consultancy: Servier; Advisory / Consultancy: Symphogen; Advisory / Consultancy: Taiho; Advisory / Consultancy: VCN Biosciences; Advisory / Consultancy: Biocartis; Advisory / Consultancy: Foundation Medicine; Advisory / Consultancy: HalioDX SAS. R. Dienstmann: Advisory / Consultancy, Speaker Bureau / Expert testimony: Roche; Speaker Bureau / Expert testimony: Symphogen; Speaker Bureau / Expert testimony: Ipsen; Speaker Bureau / Expert testimony: Amgen; Speaker Bureau / Expert testimony: Sanofi; Speaker Bureau / Expert testimony: MSD; Speaker Bureau / Expert testimony: Servier; Research grant / Funding (self): Merck. All other authors have declared no conflicts of interest.

Background So far, no biomarkers of response to anti-angiogenic drugs are available in colorectal cancer (CRC) treatment. Liquid biopsy technique identifies actionable targets in CRC patients (pts), tracking dynamic mutational changes. We and others described RAS mutant allele fraction in plasma (plMAF) as an independent prognostic marker in metastatic CRC (mCRC). Here, we explored the predictive value of plMAF in RAS mutant pts treated in first line with chemotherapy +/- bevacizumab (bev). Methods A multicentric prospective/retrospective analysis was conducted. We collected data from 226 mCRC pts and selected the subset not eligible for metastasis resection that had basal plMAF sample evaluable for RAS mutant MAF quantification using digital PCR (BEAMing). Pts were stratified as high (≥ 5.8%) or low ( Results From October 2017 to May 2019, BEAMing analysis from 62 basal plasma samples was performed. 42 pts (67.7%) were classified as high and 20 pts (32,3%) as low plMAF. Among high RAS plMAF, 24 pts received FOLFOX+bev (57%) and 20 pts FOLFOX alone (43%). In this high plMAF subgroup, a statistically significant longer PFS favouring FOLFOX+bev was observed when compared to FOLFOX alone (10.7 versus 6.9 months, respectively; HR: 0.30; p = 0.002). In the low RAS plMAF subgroup, no differences in terms of PFS were observed in either arm (8.9 versus 8.7 months, respectively; HR: 0.70; p = 0.6). Multivariate PFS model showed no association between RAS plMAF and clinicopathological variables, except for high RAS plMAF and treatment benefit with FOLFOX+bev. Conclusions Our results indicate that tumor-borne RAS plMAFs may constitute a potential predictive biomarker of efficacy for anti-angiogenic agents in mCRC. Confirmatory studies in randomized cohorts will be performed. Legal entity responsible for the study VHIO (Vall d’Hebron Institute of Oncology). Funding AECC (Asociacion Espanola Contra el Cancer). Disclosure G. Martini: Research grant / Funding (self), Research Project supported by ESMO with the aid of a grant from Amgen: ESMO-AMGEN. E. Elez: Honoraria (self): Merck Serono; Honoraria (self): Sanofi; Honoraria (self): MSD; Honoraria (self): Roche; Honoraria (self): Servier; Honoraria (self): Amgen; Honoraria (self): Array. G. Argiles Martinez: Honoraria (self), Honoraria (institution), Research grant / Funding (self), Travel / Accommodation / Expenses: Hoffmann-LaRoche, Bristol-Myers Squibb, Bayer, Servier, Amgen, Merck Serono, Menarini; Honoraria (self): Menarini; Honoraria (institution): Boston Pharmaceuticals; Honoraria (institution): Genentech; Honoraria (institution): Boehringer Ingelheim. M.J. Ortiz Morales: Speaker Bureau / Expert testimony: Amgen; Speaker Bureau / Expert testimony: Roche; Speaker Bureau / Expert Testimony: Sanofi. P.G. Nuciforo: Honoraria (self): BAYER; Honoraria (self): MSD; Honoraria (self): Novartis. R. Dienstmann: Advisory / Consultancy, Speaker Bureau / Expert testimony: Roche; Speaker Bureau / Expert testimony: Symphogen, Ipsen, Amgen, Sanofi, MSD, Servier; Research grant / Funding (self): MERCK. J. Tabernero: Advisory / Consultancy: Array Biopharma, AstraZeneca, Bayer, BeiGene, Boehringer Ingelheim, Chugai, Genentech, Inc., Genmab A/S, Halozyme, Imugene Limited, Inflection Biosciences Limited, Ipsen, Kura Oncology, Lilly, MSD, Menarini, Merck Serono, Merrimack, Merus, Molecular Part. E. Aranda Aguilar: Advisory / Consultancy: Amgen; Advisory / Consultancy: Bayer; Advisory / Consultancy: Celgene; Advisory / Consultancy: Merck; Advisory / Consultancy: Roche; Advisory / Consultancy: Sanofi. A. Vivancos: Advisory / Consultancy: sysmex; Advisory / Consultancy: Novartis; Advisory / Consultancy: Merck; Advisory / Consultancy: Bristol-Meyers Squidd; Advisory / Consultancy: Guardant Health. All other authors have declared no conflicts of interest.

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187 Background: BTCs are rare, aggressive malignancies with poor prognoses. Treatment options and outcomes after first-line therapy are not well defined. Median progression-free survival (PFS) in second-line BTC is < 5 mo. Combined BRAF + MEK inhibition is efficacious in BRAF V600–mutated anaplastic thyroid cancer, melanoma, and lung cancer, but less so in BRAF V600E-mutated colorectal cancer. Activating BRAF V600E mutations have been reported in 0% to 20% of BTCs; thus, D (BRAF inhibitor) + T (MEK inhibitor) was evaluated as a treatment for pts with BRAF V600E–mutated BTC in the ROAR basket trial. Methods: In this phase II, open-label trial, pts with BRAF V600E mutations in 9 rare tumor types, including BTC, received D (150 mg BID) + T (2 mg QD) until unacceptable toxicity, disease progression, or death. Eligible pts had advanced or metastatic cancer and had been treated with ≥ 1 prior systemic therapy. The primary endpoint was investigator-assessed overall response rate (ORR). Secondary endpoints included duration of response (DOR), PFS, overall survival (OS), biomarker correlates, and safety. Results: Thirty-three pts with BTC had enrolled at data cutoff (January 3, 2018). BRAF V600E mutations were centrally confirmed in 30 of 33 pts with BTC (91%). Median age was 58 y, and 78% had received ≥ 2 prior lines of systemic therapy. 32 of 33 pts with BTC were evaluable. Investigator-assessed ORR was 41% (13/32; 95% CI, 24%-59%), with 6 of 13 responses ongoing at data cutoff, 7 of 13 pts (54%) had a DOR ≥ 6 mo. Median PFS was 7.2 mo (95% CI, 4.6-10.1 mo), and median OS was 11.3 mo (95% CI, 7.3-17.6 mo). Grade 3/4 adverse events in ≥ 3 pts were increased γ-glutamyltransferase (n = 3 [9%]) and decreased white blood cell count (n = 3 pts [9%]). Biomarker analyses demonstrate a heterogeneous genetic landscape, and suggest a higher baseline expression of MAPK pathway genes in the pts who did not respond to D + T. Conclusions: D + T demonstrated promising efficacy in pts with BTC, with a favorable safety profile. These pts should be considered for BRAF mutation analysis, and D + T should be considered for pts with BRAF V600E-mutated BTC. Clinical trial information: NCT02034110.

688 Background: BRAFV600E mutation occurs in 10%-–15% of patients (pts) with mCRC and confers a poor prognosis. After first-line therapy, standard second-line therapies provide limited benefit, with objective response rates (ORRs) < 10%, and overall survival (OS) of 4–6 months (mo). BEACON CRC (NCT02928224) is a 3-arm phase 3 trial of triplet therapy with the BRAF inhibitor ENCO + MEK inhibitor BINI + anti–EGFR antibody CETUX vs ENCO + CETUX vs a control arm (irinotecan/FOLFIRI + CETUX) in pts with BRAFV600E mCRC in the second or third-line setting. A safety lead-in (SLI) of the triplet therapy was conducted in 30 pts prior to initiation of the randomized part of the trial. Previously reported confirmed ORR in 29 pts with BRAFV600E mCRC was 48% and median progression-free survival (PFS) was 8.0 mo (Van Cutsem E, et al. Ann Oncol. 2018;29:O-027). Here we present updated safety and efficacy results including mature OS. Methods: All pts in the SLI received ENCO 300 mg once daily + BINI 45 mg twice daily + CETUX standard weekly dose. Assessments included efficacy (ORR, duration of response, time to response, PFS, and OS), safety, and tolerability. Results: Among 30 pts treated, 1 had a BRAF non-V600E mutation and is not included in the efficacy analyses. At data cutoff, the median follow-up time for survival was 18.2 mo and median exposure was 7.8 mo (range 0.5–21.4 mo). The confirmed ORR and median PFS remain unchanged from the previous report (ORR, 48% [95%CI, 29.4–67.5]; PFS, 8.0 mo [95% CI, 5.6–9.3 mo]). Mature median OS is 15.3 mo (95% CI, 9.6 mo–not reached). The triplet continues to be well-tolerated with no unexpected toxicities. The most common grade 3/4 toxicities were fatigue (13%), anemia, increases in creatine phosphokinase and/or aspartate aminotransferase, and urinary tract infections (each 10%). The rate of grade 3/4 skin toxicities continues to be lower than generally observed with CETUX in mCRC. Conclusions: With longer follow-up, triplet therapy with ENCO + BINI + CETUX continues to be well tolerated. Median PFS and now mature median OS are substantially improved over historical data for current standard-of-care options. Clinical trial information: NCT02928224.

TPS718 Background: 5-FU-containing regimens with oxaliplatin or irinotecan and a biologic agent such as the VEGF inhibitor bevacizumab (BEV) are standard-of-care (SOC) options for the treatment of first-line (1L) metastatic colorectal cancer (mCRC). However, the objective response rate (ORR) with these regimens is 38%, and median progression-free survival (PFS) and median overall survival (OS) are 9.4 months and 21.3 months, respectively (Saltz et al. JCO 2007). Thus, there is a need for therapies that will provide durable clinical responses and improved survival. mCRC tumors represent classic “cold” tumors characterized by low expression of inflammatory and immune signatures. Emerging evidence suggests that there may be subtypes of mCRC that could benefit from synergistic immunogenic stimuli with immunotherapy agents combined with other compounds. The immune checkpoint inhibitor nivolumab (NIVO) enhances antitumor T-cell activity through the inhibition of the programmed death-1 receptor. Chemotherapy and BEV may have potential synergistic immune-stimulatory effect on the tumor and its microenvironment. Therefore, combining NIVO with SOC may enhance the antitumor immune response and improve clinical activity in 1L mCRC. The international, multicenter, open-label phase 2/3 CheckMate-9X8 (NCT03414983) trial will evaluate efficacy and safety of the combination of NIVO+SOC, compared with SOC alone, in previously untreated patients with mCRC. Methods: An estimated 180 patients aged ≥ 18 years with histologically confirmed mCRC, no prior therapy for mCRC, Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, and an adequate tissue sample, will be randomized to receive either NIVO+SOC or SOC alone. Patients who have had prior treatment with a checkpoint inhibitor; have autoimmune, cardiovascular, or hepatic disease; or test positive for hepatitis B or C (indicating detectable virus) will be excluded. The primary endpoint is PFS assessed by blinded independent central review (BICR) using RECIST v1.1. Secondary endpoints include ORR, disease control rate, duration of response, and time to response, all by BICR; OS; and safety. Clinical trial information: NCT03414983.

Purpose: Within the aim of advancing precision oncology, we have generated a collection of patient-derived xenografts (PDX) characterized at the molecular level, and a preclinical model of colon cancer metastasis to evaluate drug-response and tumor progression. Experimental Design: We derived cells from 32 primary colorectal carcinomas and eight liver metastases and generated PDX annotated for their clinical data, gene expression, mutational, and histopathological traits. Six models were injected orthotopically into the cecum wall of NOD-SCID mice in order to evaluate metastasis. Three of them were treated with chemotherapy (oxaliplatin) and three with API2 to target AKT activity. Tumor growth and metastasis progression were analyzed by positron emission tomography (PET). Results: Patient-derived cells generated tumor xenografts that recapitulated the same histopathological and genetic features as the original patients' carcinomas. We show an 87.5% tumor take rate that is one of the highest described for implanted cells derived from colorectal cancer patients. Cecal injection generated primary carcinomas and distant metastases. Oxaliplatin treatment prevented metastasis and API2 reduced tumor growth as evaluated by PET. Conclusions: Our improved protocol for cancer cell engraftment has allowed us to build a rapidly expanding collection of colorectal PDX, annotated for their clinical data, gene expression, mutational, and histopathological statuses. We have also established a mouse model for metastatic colon cancer with patient-derived cells in order to monitor tumor growth, metastasis evolution, and response to treatment by PET. Our PDX models could become the best preclinical approach through which to validate new biomarkers or investigate the metastatic potential and drug-response of individual patients. Clin Cancer Res; 19(24); 6787–801. ©2013 AACR.

Colorectal cancer (CRC) is a leading cause of cancer death worldwide. Over the last decade, the addition of antibodies that block the epidermal growth factor receptor (EGFR) or angiogenesis to the classic chemotherapy backbone has improved overall survival in metastatic colorectal cancer (mCRC). However, the role of the other major targeted therapy, the tyrosine kinase inhibitors (TKIs), is not yet fully clarified.This review discusses key published and ongoing studies with TKIs in mCRC, the mechanisms of resistance to standard treatments that are potentially targetable with these small molecules, along with the role of biomarkers in therapeutic decision-making process.The current effectiveness of TKIs is limited by two principal reasons, firstly the use of combination chemotherapy necessitates lower dose-density to manage the toxicity profile and secondly, development of these drugs has mainly been performed in molecularly unselected populations. mCRC is a heterogeneous and dynamic disease, and clinical trials with TKIs must be designed on the basis of specific molecular alterations targeted by these drugs. Success with this approach relies on identifying mutations at the time of progression, raising the importance of minimally-invasive monitoring tools. Liquid biopsies are a promising option, although this technique remains to be validated. Overall, this approach contributes to the move towards personalized and precision therapeutic strategies.

Background Patients with metastatic colorectal cancer whose disease has progressed on oxaliplatin- and irinotecan-containing regimens may benefit from EGFR-inhibiting monoclonal antibodies if they do not contain mutations in the KRAS gene (are “wild type”). It is unknown whether these antibodies, such as cetuximab, are more efficacious in refractory metastatic colorectal cancer as monotherapy, or in combination with irinotecan. Lack of mutation in KRAS, BRAF and PIK3CA predicts response to EFGR-inhibitors. The ICECREAM trial examines the question of monotherapy versus combination with chemotherapy in two groups of patients: those with a “quadruple wild type” tumour genotype (no mutations in KRAS, NRAS, PI3KCA or BRAF genes) and those with the specific KRAS mutation in codon G13D, for whom possibly EGFR-inhibitor efficacy may be equivalent. Methods and design ICECREAM is a randomised, phase II, open-label, controlled trial comparing the efficacy of cetuximab alone or with irinotecan in patients with “quadruple wild type” or G13D-mutated metastatic colorectal cancer, whose disease has progressed on, or who are intolerant of oxaliplatin- and fluoropyrimidine-based chemotherapy. The primary endpoint is the 6-month progression-free survival benefit of the treatment regimen. Secondary endpoints are response rate, overall survival, and quality of life. The tertiary endpoint is prediction of outcome with further biological markers. International collaboration has facilitated recruitment in this prospective trial of treatment in these infrequently found molecular subsets of colorectal cancer. Discussion This unique trial will yield prospective information on the efficacy of cetuximab and whether this is further enhanced with chemotherapy in two distinct populations of patients with metastatic colorectal cancer: the “quadruple wild type”, which may ‘superselect’ for tumours sensitive to EGFR-inhibition, and the rare KRAS G13D mutated tumours, which are also postulated to be sensitive to the drug. The focus on establishing both positive and negative predictive factors for the response to targeted therapy is an attempt to improve outcomes, reduce toxicity and contain treatment costs. Tissue and blood will yield a resource for molecular studies. Recruitment, particularly of patients with the rare G13D mutation, will demonstrate the ability for international collaboration to run prospective trials in small colorectal cancer molecular subgroups. Trial registration Australian and New Zealand Clinical Trials Registry: ACTRN12612000901808, registered 16 August 2012.

Purpose RAS mutations predict lack of response to epidermal growth factor receptor monoclonal antibody therapy in patients with metastatic colorectal cancer (mCRC), but preclinical studies and retrospective clinical data suggest that patients with tumors harboring the exon 2 KRAS G13D mutation may benefit from cetuximab. We aimed to assess cetuximab monotherapy and cetuximab plus irinotecan in patients with molecularly selected (G13D mutation) chemotherapy-refractory mCRC in a randomized phase II trial of this rare molecular subtype. Patients and Methods Patients with chemotherapy-refractory KRAS G13D mutation–positive mCRC who had progressed within 6 months of irinotecan therapy were randomly assigned to cetuximab 400 mg/m2 loading dose and then 250 mg/m2 once per week with or without irinotecan 180 mg/m2 once every 2 weeks. The primary end point was 6-month progression-free survival; secondary end points were response rate, overall survival, quality of life, and toxicity. Results Fifty-one of 53 patients recruited over 2 years were eligible. The 6-month progression-free survival rate was 10% (95% CI, 2% to 26%) for cetuximab versus 23% (95% CI, 9% to 40%) for cetuximab plus irinotecan with a hazard ratio of 0.74 (95% CI, 0.42 to 1.32). Response and stable disease rates were 0% and 58% for monotherapy versus 9% and 70% for combination treatment, respectively. Overall survival and quality of life were similar; toxicities were higher with combination therapy. Conclusion In patients with G13D-mutated chemotherapy-refractory mCRC, there was no statistically significant improvement in disease control at 6 months with either cetuximab monotherapy or cetuximab plus irinotecan. No responses were seen with single-agent cetuximab. The responses observed with the combination of cetuximab and irinotecan may reflect true drug synergy or persistent irinotecan sensitivity. The ICECREAM (Irinotecan Cetuximab Evaluation and Cetuximab Response Evaluation Among Patients with a G13D Mutation) study demonstrates the need to prospectively evaluate hypotheses that were previously supported by retrospective analyses and exemplifies the value of international collaboration in trials of rare molecular subtypes.

Purpose: Aurora A kinase (AAK) is a key regulator of mitosis and a target for anticancer drug development. This phase I study investigated the safety, pharmacokinetics, and pharmacodynamics of MLN8237 (alisertib), an investigational, oral, selective AAK inhibitor, in 59 adults with advanced solid tumors. Experimental Design: Patients received MLN8237 once daily or twice daily for 7, 14, or 21 consecutive days, followed by 14 days recovery, in 21-, 28-, or 35-day cycles. Dose-limiting toxicities (DLT) and the maximum-tolerated dose (MTD) for the 7- and 21-day schedules were determined. Pharmacokinetic parameters were derived from plasma concentration–time profiles. AAK inhibition in skin and tumor biopsies was evaluated and antitumor activity assessed. Results: Neutropenia and stomatitis were the most common DLTs. The MTD for the 7- and 21-day schedules was 50 mg twice daily and 50 mg once daily, respectively. MLN8237 absorption was fast (median time to maximum concentration, 2 hours). Mean terminal half-life was approximately 19 hours. At steady state, pharmacodynamic effects were shown by accumulation of mitotic and apoptotic cells in skin, and exposure-related increases in numbers of mitotic cells with characteristic spindle and chromosomal abnormalities in tumor specimens, supporting AAK inhibition by MLN8237. Stable disease was observed and was durable with repeat treatment cycles, administered over 6 months, in 6 patients, without notable cumulative toxicity. Conclusions: The recommended phase II dose of MLN8237 is 50 mg twice daily on the 7-day schedule, which is being evaluated further in a variety of malignancies, including in a phase III trial in peripheral T-cell lymphoma. Clin Cancer Res; 18(17); 4764–74. ©2012 AACR.

Panitumumab is a fully human, monoclonal antibody targeting the EGF receptor with proven clinical activity in KRAS wild-type metastatic colorectal carcinoma. Treatment with panitumumab has been shown to significantly improve response rate and progression-free survival in this subgroup of patients, with a manageable toxicity profile. Panitumumab’s first worldwide indication was as a single agent in chemorefractory patients. Recently, the EMA approved its use as part of a chemotherapy regimen in first- and second-line settings, following the encouraging results of large randomized Phase III trials. In order to identify patients with higher chances of benefiting from the treatment, additional molecular aberrations in the EGF receptor signaling pathway are being investigated as predictive biomarkers. In this article we review 10 years of drug development, focusing on the clinical evidence for panitumumab’s indication in metastatic colorectal cancer and future strategies of investigation.

Cetuximab was approved using a weekly schedule, alone or in combination with chemotherapy (CT). However, many CT regimens in metastatic colorectal cancer (CRC) are delivered every 2 weeks (q2wks). Preliminary data suggested that a simplified schedule using cetuximab q2wks, 500 mg/m² would be equivalent to the standard weekly administration. Medical data of all patients with advanced CRC who received cetuximab q2wks were retrospectively collected and checked for consistency by an independent monitor in 4 European centers. Ninety-one patients were treated between 2005 and 2007 when the K-RAS mutational status of tumors was not determined routinely. They received a median of 4 (0-5) previous drugs, including previous weekly cetuximab in 38.5% of patients. Cetuximab q2wks was associated with an irinotecan-based regimen in 85.7% of patients. The median number of cetuximab administrations was 6 (1-23). Skin toxicity was observed in 68.2% of evaluable patients (grade 3 in 15%). Only one grade 1 allergy was reported. In the 84 patients beyond first-line therapy, response rate was 29.3%. The median progression-free survival was 3.0 months (range 2.2-3.8), and median overall survival was 9.0 months (range 6.2-11.8). Cetuximab q2wks appears safe and effective in heavily pretreated patients and convenient in combination with q2wks CT schedules.

This phase I trial examined the safety, pharmacokinetics, and pharmacodynamics of MLN8054, an oral, selective, small-molecule inhibitor of Aurora A kinase. Patients with advanced solid tumors received increasing doses of MLN8054 in 28-day cycles until dose-limiting toxicity (DLT) was seen in ≥2 of 3-6 patients in a cohort. For the 10-mg and 20-mg cohorts, treatment was administered once daily on days 1 to 5 and 8 to 12. Patients in later cohorts (25, 35, 45, 55, 60, 70, and 80 mg/day) were treated four times daily on days 1 to 14, with the largest dose at bedtime (QID-14D) to mitigate benzodiazepine-like effects possibly associated with peak plasma concentrations. Patients (n = 43) received a median of 1 cycle (range, 1–10). DLT of somnolence was first noted in the 20-mg cohort. Two DLTs of somnolence (n = 1) and transaminitis (n = 1) were seen at QID-14D 80 mg. Grade 2 oral mucositis (n = 1), predicted to be a mechanistic effect, was observed only at QID-14D 80 mg. MLN8054 exposure levels were roughly linear with dose; terminal half-life was 30 to 40 hours. Pharmacodynamic analyses of skin and tumor mitotic indices, mitotic cell chromosome alignment, and spindle bipolarity provided evidence of Aurora A inhibition. MLN8054 dosing for 10 to 14 days in 28-day cycles was feasible. Somnolence and transaminitis were DLTs. Pharmacodynamic analyses in mitotic cells of both skin and tumor provided proof of mechanism for Aurora A kinase inhibition. A more potent, selective, second-generation Aurora A kinase inhibitor, MLN8237, is in clinical development. Mol Cancer Ther; 9(10); 2844–52. ©2010 AACR.

2523Background: BI 836880 (q3w or qw, iv) was evaluated in two first-in-human, Phase I trials in pts with advanced/metastatic solid tumors. We report exploratory PK/PD analysis of these studies to ...

3551Background: Pts with MSS all-RAS and BRAFV600E wild-type met CRC are more likely to respond to anti-EGFR drugs, irrespective of treatment (tx) line, particularly if left-sided primaries (prim)....

2586Background: CRAF is a key mediator of oncogenic mitogen-activated protein kinase (MAPK) pathway reactivation following MEK or BRAF inhibition. LXH254 is a BRAF and CRAF inhibitor with antitumor...

e24013Background: VEGF and Ang-2 are often overexpressed in human cancers and the VEGF/VEGFR2 and Ang-2/Tie-2 pathways are established independent therapeutic targets. Given the crosstalk between t...

627 Background: The SLI of the BEACON CRC phase 3 study assessed the safety and efficacy of the combination of the BRAF inhibitor encorafenib (ENCO) + MEK inhibitor binimetinib (BINI) + anti-EGFR antibody cetuximab (CETUX) in pts with BRAFV600E-mutant mCRC after 1 or 2 prior regimens. CEA and CA19-9 are tumor markers that are widely used to monitor the effectiveness of systemic therapies for mCRC; here we report on the association of CEA and CA19-9 changes while on treatment with clinical outcomes in pts from the SLI. Methods: Pts in the SLI received the triplet of ENCO 300 mg QD + BINI 45 mg BID + CETUX 400 mg/m2 (initial dose) then 250 mg/m2 QW in 28-day cycles. Pts were evaluated for safety, radiographic response, and change in tumor markers CEA and CA19-9. Results: 30 pts were treated. The triplet was generally well tolerated, and adverse events were consistent with known BRAF, MEK, and EGFR inhibitor toxicities. The rate of severe skin toxicities (grade 3/4) was lower than generally observed for CETUX in mCRC. Of the 29 pts with a BRAFV600E mutation, the median time on study treatment was 5.6 mo (range, 1.0–9.3 mo), and 22 (76%) remained on study treatment at the time of data cutoff. The confirmed overall response rate (ORR) was 41%, with 1 complete and 11 partial responses. In addition, 9 pts had prolonged stable disease (SD) up to 9.3 mo.CEA and CA19-9 were analyzed in 28 pts. CEA and CA19-9 decreased in 96% and 82% of these pts, respectively. Among 15 pts with treatment duration ≥5.6 mo, median/mean % decreases were 97%/79% for CEA and 92%/82% for CA19-9 in confirmed responders (n=6). Respective decreases in pts with prolonged SD (n=9) were similar: 84%/68% for CEA and 89%/68% for CA19-9. Updated safety, efficacy, and tumor marker results will be provided. Conclusions: ENCO + BINI + CETUX is generally well tolerated and has encouraging clinical activity in BRAFV 600E mCRC, with a confirmed ORR of 41%. In pts with study treatment duration ≥5.6 mo, the tumor markers CEA and CA19-9 decreased markedly and to the same degree in responders vs pts with prolonged SD, providing additional evidence of the meaningful clinical activity of this regimen. Clinical trial information: NCT02928224.

Purpose of review In the last years, interesting advances have been reported in the treatment of infrequent digestive tumors. The increasing development of new targeted therapies in human cancer has also impacted in these rare gastrointestinal malignancies providing a wide range of possibilities in the design of future clinical trials. Recent findings The inhibition of angiogenesis and the blockage of the epidermal growth factor receptor pathway have provided the most interesting activity in recently reported studies for esophageal and biliary tract carcinomas. Additionally, several targeted therapies have been developed to target the main kinase proteins of the most important pathways of these malignancies. The results of the biggest phase III trial in locally advanced anal carcinoma have been recently published. Finally, the inhibition of epidermal growth factor receptor has also showed promising activity in anal carcinomas. Summary Recent advances in the knowledge of molecular mechanism of carcinogenesis have led to meaningful changes in the management of gastrointestinal cancers. Although the major advances in targeted therapy have been introduced in the treatment of colorectal cancer, new interesting approaches have been reported in less frequent gastrointestinal tumors such as esophageal, biliary tract, and anal canal carcinoma opening a new hope in the treatment of these rare tumors in the molecular targeted therapy era.

Colorectal cancer is one of the most frequently diagnosed malignancies in men and women and despite recent advances the prognosis of metastatic colorectal cancer remains poor. A better understanding of the molecular pathways that characterize tumor growth has provided novel targets in cancer therapy. Several proteins have been implicated as having a crucial role in metastatic colorectal cancer. Targets are defined according to their cellular localization, such as membrane receptor targets, intracellular signaling targets and protein kinases that regulate cell division. In the last 5 years, cetuximab, panitumumab and bevacizumab have been approved for the treatment of metastatic colorectal cancer and emerging data on the clinical development of new drugs, other than EGF-receptor and VEGF inhibitors, are likely to provide novel opportunities in the treatment of this malignancy.

Major advances with new molecular agents have translated in the last decade in a survival benefit in those patients with advanced cancer disease and in a cure rate improvement in those treated in the adjuvant setting. Some of these targeted agents have been approved by the regulatory agencies and are now used in daily clinical practice. In general, targeted molecular therapies have a good toxicity profile; nevertheless, new types of toxicity have been reported with the use of these new agents.

Colorectal cancer (CRC) is one of the leading causes of cancer deaths worldwide. Despite the introduction of several new drugs targeting the vascular endothelial growth factor or epidermal growth factor receptor (EGFR) signaling pathways, survival and disease control in metastatic CRC remains poor.Chemotherapy based on fluoropyrimidines and irinotecan or oxaliplatin has been the cornerstone of CRC standard of care for several decades. Optimal regimens are selected according to toxicity profiles and patient characteristics. The addition of targeted drugs inhibiting angiogenesis, notably bevacizumab, aflibercept and ramucirumab, has improved chemotherapy outcomes in metastatic CRC. Anti-EGFR agents, cetuximab and panitumumab, in combination with chemotherapy have also improved survival in patients with wild-type RAS tumors. In the refractory setting, there are emerging drugs such as regorafenib or TAS-102 that also have demonstrated impact on outcomes.Drugs targeting signaling pathways involved in tumorigenesis improve patient outcomes over chemotherapy alone. Determining the most suitable combination and sequence should be carefully selected, with studies yet to provide a definitive solution to this unknown. Molecular mechanisms of colorectal cancer are at the forefront of research. Knowledge in this domain will help overcome resistance to therapies and introduce new drugs in the personalized CRC therapeutic scenario.

Background & Aims There are few validated biomarkers that can be used to predict outcomes for patients with colorectal cancer. Part of the challenge is the genetic and molecular heterogeneity of colorectal tumors not only among patients, but also within tumors. We have explored intratumor heterogeneity at the epigenetic level, due to its dynamic nature. We analyzed DNA methylation profiles of the digestive tract surface and the central bulk and invasive front regions of colorectal tumors. Methods We determined the DNA methylation profiles of >450,000 CpG sites in 3 macrodissected regions of 79 colorectal tumors and 23 associated liver metastases, obtained from 2 hospitals in Spain. We also analyzed samples for KRAS and BRAF mutations, 499,170 single nucleotide polymorphisms, and performed immunohistochemical analyses. Results We observed differences in DNA methylation among the 3 tumor sections; regions of tumor−host interface differed the most from the other tumor sections. Interestingly, tumor samples collected from areas closer to the gastrointestinal transit most frequently shared methylation events with metastases. When we calculated individual coefficients to quantify heterogeneity, we found that epigenetic homogeneity was significantly associated with short time of relapse-free survival (log-rank P = .037) and short time of overall survival (log-rank P = .026) in patients with locoregional colorectal cancer. Conclusions In an analysis of 79 colorectal tumors, we found significant heterogeneity in patterns of DNA methylation within each tumor; the level of heterogeneity correlates with times of relapse-free and overall survival.

The clinical significance of low-frequent RAS pathway–mutated alleles and the optimal sensitivity cutoff value in the prediction of response to anti-EGFR therapy in metastatic colorectal cancer (mCRC) patients remains controversial. We aimed to evaluate the added value of genotyping an extended RAS panel using a robust nanofluidic digital PCR (dPCR) approach. A panel of 34 hotspots, including RAS (KRAS and NRAS exons 2/3/4) and BRAF (V600E), was analyzed in tumor FFPE samples from 102 mCRC patients treated with anti-EGFR therapy. dPCR was compared with conventional quantitative PCR (qPCR). Response rates, progression-free survival (PFS), and overall survival (OS) were correlated to the mutational status and the mutated allele fraction. Tumor response evaluations were not available in 9 patients and were excluded for response rate analysis. Twenty-two percent of patients were positive for one mutation with qPCR (mutated alleles ranged from 2.1% to 66.6%). Analysis by dPCR increased the number of positive patients to 47%. Mutated alleles for patients only detected by dPCR ranged from 0.04% to 10.8%. An inverse correlation between the fraction of mutated alleles and radiologic response was observed. ROC analysis showed that a fraction of 1% or higher of any mutated alleles offered the best predictive value for all combinations of RAS and BRAF analysis. In addition, this threshold also optimized prediction both PFS and OS. We conclude that mutation testing using an extended gene panel, including RAS and BRAF with a threshold of 1% improved prediction of response to anti-EGFR therapy. Mol Cancer Ther; 15(5); 1106–12. ©2016 AACR.

BackgroundBRAF V600 mutations occur in various nonmelanoma cancers. We undertook a histology-independent phase 2 “basket” study of vemurafenib in BRAF V600 mutation–positive nonmelanoma cancers. MethodsWe enrolled patients in six prespecified cancer cohorts; patients with all other tumor types were enrolled in a seventh cohort. A total of 122 patients with BRAF V600 mutation–positive cancer were treated, including 27 patients with colorectal cancer who received vemurafenib and cetuximab. The primary end point was the response rate; secondary end points included progression-free and overall survival. ResultsIn the cohort with non–small-cell lung cancer, the response rate was 42% (95% confidence interval [CI], 20 to 67) and median progression-free survival was 7.3 months (95% CI, 3.5 to 10.8). In the cohort with Erdheim–Chester disease or Langerhans’-cell histiocytosis, the response rate was 43% (95% CI, 18 to 71); the median treatment duration was 5.9 months (range, 0.6 to 18.6), and no patients had diseas...

This is the first study that seeks to establish the prognostic value of circulating tumor cell (CTC) (determined by CellSearch system) in patients with stage III CRC. Our results suggest that given the low number of CTC in patients with localized CRC and the particular pattern of metastatic dissemination in patients with CRC, it is likely that CTC does not have a prognostic role in this setting. Background The prognostic role of circulating tumor cells (CTC) in early colorectal cancer (CRC) has not been determined yet. We evaluated the potential prognostic value of CTC in stage III CRC patients. Patients and methods Prospective multicenter study of 519 patients with stage III CRC recruited between January 2009 and June 2010. CTC were enumerated with the CellSearch System after primary tumor resection and before the start of adjuvant therapy. A total of 472 patients were included in the analysis. Results CTC ≥1, ≥2, ≥3 and ≥5 were detected in 166 (35%), 93 (20%), 57 (12%) and 34 (7%) patients, respectively. Median follow-up was 40 months. In the overall population, CTC ≥1 (disease-free survival (DFS): HR 0.97,P = 0.85; overall survival (OS): HR 1.03,P = 0.89), ≥2 (DFS: HR 1.07,P = 0.76; OS: HR 1.02,P = 0.95), ≥3 (DFS: HR 0.96,P = 0.87; OS: HR 0.74,P = 0.41) and ≥5 (DFS: HR 0.72,P = 0.39; OS: HR 0.48,P = 0.21) were not associated with worse DFS and OS. No clinicopathological characteristics were significantly associated with the presence of CTC. In patients with disease relapse, the proportion with CTC ≥1 was not significantly different between those with single versus multiple metastatic locations (37.9% versus 31.4%,P = 0.761). In the multivariate analysis, CTC ≥1 was not an independent prognostic factor for DFS (HR 0.97,P = 0.87) and OS (HR 0.96,P = 0.89). Conclusion CTC detection was not associated with worse DFS and OS in patients with stage III CRC. Given the scarcity of CTC in these patients, it is likely that CTC determined by CellSearch system does not have a prognostic role in this setting. However, a longer follow-up is needed.

3071 Background: Mismatch repair deficient cancers harbor high levels of microsatellite instability and somatic mutations. Treatment with anti-PD-1 antibodies has resulted in durable objective responses in MSI-H cancer. As part of the ongoing, global, multicenter phase 2 studies KEYNOTE(KN)164 and KN158, we assessed the efficacy of pembrolizumab in patients (pts) with MSI-H tumors. Methods: Both studies enrolled pts with MSI-H status determined locally by IHC or PCR. KN164 enrolled pts with MSI-H CRC and ≥2 prior therapies, whereas the multicohortKN158 study included pts with MSI-H non-CRC and ≥1 prior therapy. Eligible pts in both studies received pembrolizumab 200 mg Q3W until progression, unacceptable toxicity, or pt/investigator decision. Tumor response was assessed every 9 wk by independent review per RECIST v1.1. Primary endpoint was ORR. Secondary endpoints included DOR, PFS, OS, and safety. Analyses were performed in pts from KN164 and KN158 who had ≥27 wk of follow-up as of Aug 3, 2016 and Oct 19, 2016, respectively. Results: KN164 enrolled 61 pts with MSI-H CRC (90% with ≥2 prior therapies) whereas KN158 included 21 pts with MSI-H non-CRC (42% with ≥2 prior therapies). In KN158 the most common tumor types were endometrial and small intestinal cancer (n = 4 each), cholangiocarcinoma (n = 3), and gastric and pancreatic cancer (n = 2 each). Median follow-up was 7.4 mo for MSI-H CRC and 4.5 mo for MSI-H non-CRC. ORR for MSI-H CRC was 26.2% (95% CI, 15.8%-39.1%), with 15 confirmed responses and 1 unconfirmed response, and ORR for MSI-H non-CRC was 42.9% (21.8%-66.0%), with 8 confirmed responses and 1 unconfirmed response. DCR was 50.8% (n = 31; 37.7%-63.9%) for MSI-H CRC and 66.7% (n = 14; 38.4%-83.7%) for MSI-H non-CRC. Median duration of response was not reached for either MSI-H CRC or non-CRC, and 100% of responses were ongoing. Survival and safety analyses are ongoing. Conclusions: Early results from KN164 and KN158 confirm the robust antitumor activity of pembrolizumab in heavily pretreated pts with MSI-H cancers. Clinical trial information: NCT02628067; NCT02460198.

9518 Background: The benefits of BRAF + MEK inhibition (dual combo) in pts with BRAF V600-mutant ( BRAFV600) melanoma are known. Preclinical data supports inhibiting CDK 4/6 and BRAF + MEK (triple combo) to improve antitumor activity. We report safety and preliminary efficacy from a phase 1b/2 study (NCT01543698) of encorafenib (ENCO; a selective BRAF kinase inhibitor), binimetinib (BINI; a MEK inhibitor), and ribociclib (RIBO; a CDK 4/6 inhibitor). Methods: Phase 1b of this open-label, multicenter study enrolled pts with confirmed BRAFV600advanced solid tumors. Escalating doses of RIBO 100 mg-600 mg QD for 3 wk on/1 wk off were administered with ENCO 200 mg QD + BINI 45 mg BID in successive cohorts (6 pts each) until the maximum tolerated or recommended phase 2 dose (RP2D) was reached. Due to potential pharmacokinetic interactions with RIBO, the ENCO dose was lower than the dual combo RP2D (450 mg QD). Dose escalations followed an adaptive Bayesian model. In phase 2, the triple combo was tested in pts with BRAFV600melanoma naïve to prior BRAF inhibitor treatment; the primary endpoint was objective response rate (ORR) per RECIST v1.1. Results: In phase 1b (n = 21), no dose-limiting toxicities were reported and the triple combo RP2D was ENCO 200 mg QD + BINI 45 mg BID + RIBO 600 mg QD. ENCO AUC was slightly lower than at the dual combo RP2D. In phase 2 (n = 42), 59.5% pts had an ECOG PS of 0 and 43% of pts had elevated lactate dehydrogenase. The most common (≥5%) grade 3/4 toxicities were neutropenia (26.2%), increased alanine transaminase (14.3%), diarrhea (7.1%), and anemia (7.1%). Ten pts (23.8%) discontinued treatment due to an AE, of which 4 were increased transaminases. The confirmed ORR was 52.4%, including 4 complete responses, 18 partial responses, and 15 pts with stable disease. Median duration of exposure in phase 2 was 9.1 mo (range, 0.0-21.6). Median progression-free survival was 9.0 mo (95% confidence interval, 7.0-11.1). Conclusions: Triple therapy with ENCO + BINI + RIBO in this small trial of pts with high disease burden was associated with responses in over half of pts and some evidence of increased toxicity. Clinical trial information: NCT01543698.

409 Background: PC is the 4th leading cause of cancer-related death, with limited efficacy of systemic treatment (tx) beyond first-line chemotherapy (chemo). We aimed to assess the potential benefit of phase 1 trials in this setting. Methods: From 2011 to 2016, 49 pts were enrolled in 54 phase 1 trials at our institution. Clinical and molecular data were retrospectively extracted from medical records. Time to progression (TTP) was calculated from time of tx start to discontinuation due to progressive disease, and clinical benefit rate (CBr) was defined as partial response or stable disease > 4 months. Results: Median age was 58 (41-75), 69% were male, 60% had metastases in liver. Most pts received gemcitabine-based regimens (47%) or Folforinox (32%) as first-line tx (median TTP of 5.63 months [CI 95% 4.0-8.1]). Median tx line of Phase 1 trial was 3 (range 2-5). Regimens included chemo or immunotherapies (chemo-imm group) in 16 cases (12 and 4, respectively), small molecule inhibitor (SMI) as single-agent in 19 cases (SMI.1 group), and SMI in combinations in 19 cases (SMI.2 group). In 17 cases, tx was matched to genomic profile; most frequent matches were PI3K + MEK SMI or RAF SMI ( KRAS mut in 7 pts), PI3K SMI ( PTEN loss/ PIK3CA mut in 3 pts) and PD1 blockade (PDL1 high in 4 pts). There were 3 (6%) partial responses (PI3K SMI unmatched, RAF SMI matched and anti-PD1 agent matched) and 12 (24%) disease stabilizations. Median TTP in phase 1 trial was 1.9 months [CI 95% 1.6-2.5], without significant differences if matched/unmatched agent (p = 0.5) or tx given as second-line/later regimen (p = 0.5). Median TTP was 2.7 months [CI95% 1.6-10.7] with chemo-imm (control arm), 2.0 months [CI95% 1.8-5.6] with SMI.2 (HR = 1.8, p = 0.13) and 1.4 months [CI95% 1.3-2.8] with SMI.1 (HR = 3.0, p = 0.004). This difference was maintained in a multivariable model (HR = 2.9, p = 0.005). CBr with chemo-imm (38%) or SMI.2 (21%) was higher as compared with SMI.1 (5%; p = 0.06). Conclusions: Selected PC pts are eligible to phase 1 trials and up to one-third derive substantial benefit from the intervention. In our experience, chemo-imm agents or targeted SMI given as combination regimens associate with longer TTP and CBr when compared with single-agent SMI.