invited several experts to identify practice-changing or noteworthy abstracts in their field from the research presented at the 2016 ASCO Annual Meeting, held June 3-7 in Chicago. Their insights are presented here, along with a list of notable immunotherapy research developed by the Society for the Immunotherapy of Cancer. Full abstracts are available at the American Society of Clinical Oncology website, meetinglibrary.asco.org.
Robert J. Mayer, MD
Dana-Farber Cancer Institute
ESPAC-4: A multi-center, international, open label randomized controlled phase III trial of adjuvant combination chemotherapy of gemcitabine (GEM) and capecitabine (CAP), versus monotherapy gemcitabine in patients with resected pancreatic ductal adenocarcinoma. Abstract LBA4006.
The administration of 6 months of adjuvant gemcitabine chemotherapy has been shown to prolong survival in patients with pancreatic cancer; gemcitabine and 5-fluorouracil were shown to be equally effective when administered in the adjuvant setting.
In the ESPAC-4 study, 730 patients who had undergone a complete macroscopic resection of a pancreatic adenocarcinoma were randomly assigned to receive gemcitabine or a combination of gemcitabine and capecitabine.
The gemcitabine/capecitabine combination proved to be statistically superior in terms of median (28.0 months vs 25.5 months) and estimated 5-year (28.8% vs 16.3%) overall survival, and may be considered as a new standard of care.
Two abstracts addressed the efficacy of checkpoint inhibitors in patients with microsatellite unstable metastatic colorectal cancer:Programmed death-1 blockade in mismatch repair deficient colorectal cancer. Abstract 103.
This abstract provides mature data from a phase II trial in which the clinical activity of the anti-PD-1 antibody pembrolizumab was compared in 28 patients with mismatch repair-deficient colorectal cancers to that in 25 patients with mismatch repair-proficient colorectal cancers.
Pembrolizumab therapy resulted in an objective response rate of 57% in the patients with mismatch repair-deficient tumors versus 0% in the patients with mismatch repair–proficient tumors. Remarkably, the responses in the mismatch repair-deficient patients have been durable with the median overall survival time not having been reached and five patients continuing to respond at the 2-year mark.Nivolumab +/- ipilimumab in treatment (TX) of patients (pts) with metastatic colorectal cancer (mCRC) with and without high microsatellite instability (MSI-H); CheckMate-142 interim results. Abstract 3501.
In this phase II trial, 47 previously treated patients with metastatic microsatellite unstable colorectal cancers were given monotherapy with the PD-1 inhibitor nivolumab while 27 similar patients were given both nivolumab and the anti-CTLA-4 antibody ipilimumab. The monotherapy cohort experienced a 26% response rate with 46% of patients remaining free of disease progression after 6 months. The patients given combination immunotherapy experienced a 33% response rate with 67% remaining free of progression after 6 months. Only 10% of 20 patients with previously treated microsatellite-stable colorectal cancers who were given the combined immunotherapy experienced a response.
Three abstracts assessed the impact of primary tumor sideness and outcome in colorectal cancer:The relationship between primary tumor sideness and prognosis in colorectal cancer. Abstract 3505.
Prior observations have suggested that patients having colon cancers arising from the right colon have a poorer prognosis than those whose tumors arise in the left colon. This finding was confirmed through a SEER data analysis dealing with 64,770 patient with colon cancer whose disease was diagnosed between 2000 and 2012, showing that patients with metastatic disease whose tumors arose in the right colon experienced an absolute 6% poorer survival outcome than those whose tumors arose in the left colon, leading to a 32% greater likelihood of death.Impact of primary (10) tumor location on overall survival (OS) and progression free survival (PFS) in patients (pts) with metastatic colorectal cancer (mCRC): Analysis of CALGB/SWOG 80405 (Alliance). Abstract 3504.
In this 1137 patient multi-institutional cooperative group trial, patients with metastatic KRAS
wild-type colorectal cancer were randomized to receive chemotherapy with cetuximab or with bevacizumab.