‘Disappointing PFS’
In the question and answer session following the presentation, moderator Michael J. Hall, MD, of Fox Chase Cancer Center in Philadelphia, asked whether the response rate seen with the addition of panitumumab was what the investigators expected, independent of the dual–checkpoint inhibitor therapy, and “with the relatively disappointing PFS you saw, what are the plans moving forward with this regimen?”
“These are great questions and thoughts I’ve had as well,” Dr. Lee replied.
He noted that studies of other anti-EGFR and checkpoint inhibitor combinations have had relatively low response rates, and his group’s study was conducted with “an effort to try and get over this immune-cold environment that we know exists in the tumor microenvironment,” he said.
Dr. Lee also acknowledged that the response rate may have been slightly higher than that seen in other studies because of the preponderance of left colon tumors, which are generally more amenable to systemic therapy.
Regarding PFS, Dr. Lee said the analyses of durability of response are still ongoing, and the median PFS was better than that seen in a trial of single-agent panitumumab in a similar population.
The current study was funded by Amgen and Bristol Myers Squibb. Dr. Lee disclosed institutional research funding from the companies, consulting/advising for Pfizer, and travel expenses from Genentech/Roche. Dr. Hall disclosed relationships with Ambry Genetics, AstraZeneca, Caris Life Sciences, Foundation Medicine, InVitae, and Myriad Genetics. He also shares a patent with several Fox Chase investigators for a novel method to investigate hereditary CRC genes.
The Gastrointestinal Cancers Symposium is sponsored by the American Gastroenterological Association, the American Society for Clinical Oncology, the American Society for Radiation Oncology, and the Society of Surgical Oncology.
