Guest Blogger – Marc-Aurèle Chay

ASCO 2016 - image 2 The American Society of Clinical Oncology (ASCO) 2016 annual meeting took place June 3rd to 7th in Chicago, Illinois. Being the largest cancer conference in the world, it gathered doctors, researchers and biopharma giants to discuss the latest trends in cancer research. On the topic of colorectal cancer, you will find the four most promising advances that were presented at the conference below.

Combining Nivolumab and Ipilimumab to treat MSI-H mCRC: The CheckMate-142 trial
CheckMate-142, an ongoing phase II clinical trial, is testing the efficacy of combining Nivolumab with Ipilimumab for treatment of mCRC. The two drugs are hypothesized to enhance T cell antitumor activity through complementary mechanisms, and are promising for the targeting of MSI-H (microsatellite instability high) mCRC especially. With an overall response rate (ORR) of up to 33% (9/27 MSI-H patients on combination therapy having a partial remission), this combination therapy shows good potential and appears to be tolerated by most patients, although the effects seem to be more effective for MSI-H mCRC only.

A new promising combination therapy for the treatment of KRAS-mutated, non-MSI-High CRC.
A phase Ib study is investigating the combination potential of Cobimetinib (a MEK inhibitor) and Atezolizumab (an anti-PDL1 antibody) for the treatment of advanced solid tumors. Using a predefined expansion cohort of KRAS-mutated mCRC, the combination treatment achieved an ORR of 20%, with treatment related grade 3 adverse event occurring in 35% of the patients. This is a step forward in the treatment of non MSI-H mCRC, and evaluation of the combination treatment effectiveness will be continued.

More is not always better when treating CRC with chemotherapy.
STAR-01, a randomized phase III clinical trial, investigated the effects of increasing the aggressiveness of chemotherapy for the treatment of resectable locally advanced rectal cancer. They compared a standard regimen of 5FU-based chemoradiation with the same regimen + oxaliplatin. The more aggressive chemotherapy regimen did not result in improved pathological complete response or 5 year overall survival rate, but was unfortunately associated with increased toxicity.

Right-side vs left-side colorectal cancers, differences in prognosis and response to treatment.
A lot of attention was brought to the debate of the differences between left and right side colorectal cancer. A retrospective analysis of the CALGB/SWOG 80405 study showed that patients with primary tumors on the right side of the colon have a 55% higher risk for death compared with patients with primary tumors located on the left side. This finding is especially important for the designing of new drugs and drug trials, and need to be taken into account when doing randomization for studies.

And there you have it, the most promising studies presented at this year’s ASCO relating to colorectal cancer.