Author Interviews, Cancer Research, Colon Cancer / 10.07.2015
Novel Anti-Metabolite Offers New Therapeutic Option For Resistant Colon Cancer
MedicalResearch.com Interview with:
Howard S. Hochster, MD
Associate Director, Yale Cancer Center
Professor of Medicine, Yale School of Medicine
New Haven, CT 06520
Medical Research: What is the background for this study? What are the main findings?
Dr. Hochster: TAS-102 is a novel anti-metabolite, recently combined with a metabolic inhibitor to make it orally bioavailable and active in the treatment of cancer. In pre-clinical studies, it is non-cross reactive with 5FU. What this means practically is that we have another chemotherapy agent that can be used for patients with colon cancer. This drug will be an addition to the approved chemotherapy agents 5FU, oxaliplatin and irinotecan. It may be combinable with these and with targeted agents to provide new active regimens.
The main findings of the study were published in NEJM, May 15, 2015. The study enrolled 800 patients randomized (2:1 ratio) to drug vs placebo. Patients with advanced colon cancer who had been treated with all the previously approved drugs were eligible. The drug was active in reducing time to tumor growth (Progression Free Survival) by 50% and improved overall survival for treated patients by about 25%.
The data I presented at ESMO included a further analysis on specific genomic subsets of patients within the 800 patient study. All patients were tested locally for RAS mutations and about 50% had such mutations (as expected). There was no differences in benefit or toxicity for those with RAS wild-type tumors or RAS mutated tumors. We also looked at those with BRAF mutations, but only 15% of patients were tested and this mutation occurs in about 8% of colon cancer, so we had very few patients with BRAF mutation. Given this limitation, it appeared that this did not make a difference for benefit or toxicity either.
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