Molecular and genetic targets within metastatic colorectal cancer and associated novel treatment advancements

Colorectal cancer results in the deaths of hundreds of thousands of patients worldwide each year, with incidence expected to rise over the next two decades. In the metastatic setting, cytotoxic therapy options remain limited, which is reflected in the meager improvement of patient survival rates. Therefore, focus has turned to the identification of the mutational composition inherent to colorectal cancers and development of therapeutic targeted agents. Herein, we review the most up to date systemic treatment strategies for metastatic colorectal cancer based on the actionable molecular alterations and genetic profiles of colorectal malignancies.

Update on optimal treatment for metastatic colorectal cancer from the AGITG expert meeting: ESMO congress 2019

Introduction: Outcomes in metastatic colorectal cancer are improving, due to the tailoring of therapy enabled by better understanding of clinical behavior according to molecular subtype.Areas covered: A review of the literature and recent conference presentations was undertaken on the topic of systemic treatment of metastatic colorectal cancer. This review summarizes expert discussion of the current evidence for therapies in metastatic colorectal cancer (mCRC) based on molecular subgrouping.Expert opinion: EGFR-targeted and VEGF-targeted antibodies are now routinely incorporated into treatment strategies for mCRC. EGFR-targeted antibodies are restricted to patients with extended RAS wild-type profiles, with evidence that they should be further restricted to patients with left-sided tumors. Clinically distinct treatment pathways based on tumor RAS, BRAF, HER2 and MMR status, are now clinically applicable. Evidence suggests therapy for additional subgroups will soon be defined; the most advanced being for patients with KRAS G12 C mutation and gene TRK fusion defects.

Association of Industry and Academic Sponsorship With Negative Phase 3 Oncology Trials and Reported Outcomes on Participant Survival: A Pooled Analysis

Importance

Only 3.4% of cancer drugs evaluated in phase 1 trials are approved by the US Food and Drug Administration, with most failing in phase 3 trials.

Objective

To investigate whether an association exists between the sponsorship and conduct of a negative phase 3 randomized clinical trial (RCT) investigating a cancer drug that lacked supporting phase 2 trial evidence for that drug, and to evaluate the association with overall survival among patients randomized to the experimental arm of such phase 3 trials.

Data Sources

Articles in the Lancet, Lancet Oncology, JAMA, JAMA Oncology, and Journal of Clinical Oncology published between January 2016 and June 2018 were searched.

Study Selection

Phase 3 RCTs of cancer drugs that failed to improve the primary end point were selected and any prior phase 2 trial of the same drug that supported the phase 3 trial was selected without any date or journal restrictions.

Data Extraction and Synthesis

Percentages of negative phase 3 RCTs of cancer drugs that lacked any phase 2 evidence, had a negative phase 2 trial, or had a positive phase 2 study were extracted. Associations were assessed using the Fisher exact test. Pooled hazard ratios and 95% CIs for the overall survival of patients enrolled in these negative phase 3 RCTs were estimated using a random-effects model.

Main Outcomes and Measures

Negative phase 3 RCTs with a lack of a phase 2 trial or the presence of a negative phase 2 trial and overall survival of enrolled patients in the phase 3 RCTs.

Results

In this meta-epidemiological study, 67 negative phase 3 RCTs on cancer drugs, which included 64 600 patients, met the criteria of being sponsored by industry or academic groups, of which 42 RCTs (63%) were industry sponsored and the remaining 25 RCTs (37%) were academic. A phase 2 trial was not available for 28 of these trials (42%). Of 29 trials (43%) with a phase 2 trial available, 8 trials (28%) failed to meet their primary end points and 5 of those were industry sponsored. There was no association with overall survival for patients participating in these negative phase 3 RCTs (pooled hazard ratio, 0.99; 95% CI, 0.96-1.02). When the pooled analysis was limited to the 27 RCTs with a hazard ratio above 1.00, the overall pooled hazard ratio for overall survival was 1.11 (95% CI, 1.06-1.16). No association between having a negative or undefined phase 2 trial and trial sponsorship was found using the Fisher exact test.

Conclusions and Relevance

More than 40% of the negative phase 3 RCTs in oncology published in these 5 journals were conducted without a supporting phase 2 trial and were sponsored by both academia and industry. Running such trials not only may risk loss of resources owing to a failed trial but also may be associated with decreased patient survival. Further research and regulations in this area appear warranted.

Targeted therapy for metastatic colorectal cancer

INTRODUCTION

Outcomes in metastatic colorectal cancer are improving, with better understanding and use of targeted therapies. Areas covered: A review of the literature and recent conference presentations was undertaken on the topic of systemic treatment of metastatic colorectal cancer. This article reviews the current evidence for targeted therapies in advanced colorectal cancer, including up-to-date data regarding anti-epidermal growth factor receptor (EGFR) and anti-vascular endothelial growth factor (VEGF) agents, the relevance of primary tumor location and novel subgroups such as BRAF mutated, HER2 amplified, and mismatch-repair-deficient cancers. Expert commentary: EGFR-targeted and VEGF-targeted antibodies are now routinely incorporated into treatment strategies for metastatic colorectal cancer (mCRC). The use of EGFR-targeted antibodies should be restricted to patients with extended RAS wild-type profiles, and there is evidence that they should be further restricted to patients with left-sided tumors. Clinically, mCRC can be divided into subgroups based on RAS, BRAF, HER2, and MMR status, each of which have distinct treatment pathways.

Unravelling the pharmacologic opportunities and future directions for targeted therapies in gastro-intestinal cancers Part 1: GI carcinomas

Until the 1990s, cytotoxic chemotherapy has been the cornerstone of medical therapy for gastrointestinal (GI) cancers. Better understanding of the molecular biology of cancer cell has led to the therapeutic revolution of targeted therapies, i.e. monoclonal antibodies or small molecule inhibitors directed against proteins that are specifically overexpressed or mutated in cancer cells. These agents being more specific to cancer cells were expected to be less toxic than cytotoxic agents. Targeted agents have provided clinical benefit in many GI cancer types. For example, antiangiogenics and anti-EGFR therapies have significantly improved survival of patients affected by metastatic colorectal cancer and have deeply changed the therapeutic strategy in this disease. However, their effects have sometimes been disappointing, due to intrinsic or acquired resistance mechanisms (e.g., RAS mutation for anti-EGFR therapies), or to an activity restricted to some tumour settings (e.g., lack of activity in other cancer types, or on the microscopic residual disease in adjuvant setting). Many studies are negative in overall population but positive in some specific patient subgroups (e.g., trastuzumab in HER2-positive gastric cancer), illustrating the importance of patient selection and early identification of predictive biomarkers of response to these therapies. We propose a comprehensive two-part review providing a panoramic approach of the successes and failures of targeted agents in GI cancers to unravel the pharmacologic opportunities and future directions for these agents in GI oncology. In this first part, we will focus on adenocarcinomas and squamous cell carcinomas, for which targeted therapies are mostly used in combination with chemotherapy.