Merck (NYSE: MRK), known as MSD outside the U.S. and Canada, has announced that the Phase 3 KEYFORM-007 trial, which investigated the fixed-dose combination of favezelimab (Merck’s anti-LAG-3 antibody) and pembrolizumab (KEYTRUDA®), did not meet its primary goal of improving overall survival (OS) in patients with previously treated PD-L1 positive, microsatellite stable (MSS) metastatic colorectal cancer (mCRC). According to the final pre-specified analysis, the combination treatment failed to show a survival advantage over the current standard treatments, regorafenib or TAS-102 (trifluridine and tipiracil hydrochloride).
The safety profile of the combination therapy was consistent with previous studies on favezelimab and pembrolizumab, with no new safety concerns reported.
A thorough evaluation of the trial data is ongoing, and Merck plans to collaborate with investigators to present the findings to the scientific community.
“Metastatic colorectal cancer remains a tough disease to treat, particularly for the majority of patients with microsatellite stable disease, which has shown limited response to immunotherapy,” said Dr. M. Catherine Pietanza, vice president of global clinical development at Merck Research Laboratories. “We are thankful to the patients and investigators involved in this study, and we will continue our efforts to develop KEYTRUDA-based therapies and other novel treatments for colorectal cancer patients who are in need of new options.”
In the U.S., KEYTRUDA is approved for treating patients with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) colorectal cancer, as determined by an FDA-approved test. However, KEYTRUDA is not approved for treating MSS mCRC.
The fixed-dose combination of favezelimab and pembrolizumab is also being studied in other types of cancer, including hematologic malignancies and various solid tumors. Ongoing trials include KEYFORM-008, a Phase 3 study evaluating the combination in patients with relapsed or refractory classical Hodgkin lymphoma whose disease has progressed after previous anti-PD-1 therapy.
