Merck known as MSD outside of the United States and Canada, has announced the discontinuation of clinical development programs for vibostolimab, an anti-TIGIT antibody, and favezelimab, an anti-LAG-3 antibody. Vibostolimab was being evaluated in combination with pembrolizumab (KEYTRUDA®) in the KeyVibe program, while favezelimab was being tested in combination with pembrolizumab in the KEYFORM program.
The decision to discontinue these programs follows recommendations from an independent Data Monitoring Committee (DMC) and analyses of the trial data. Merck is terminating the Phase 3 KeyVibe-003 and KeyVibe-007 trials, which investigated the fixed-dose combination of vibostolimab and pembrolizumab in patients with non-small cell lung cancer (NSCLC). These trials met pre-specified futility criteria for the primary endpoint of overall survival during a pre-planned analysis. While no new safety concerns were identified, the safety profile of the combination therapy was consistent with prior studies, and as expected, dual checkpoint inhibition resulted in more immune-related adverse events compared to pembrolizumab alone. Based on the cumulative data, Merck has also decided to halt the Phase 3 KeyVibe-006 trial and other vibostolimab-related studies.
Separately, Merck is ending the favezelimab clinical development program, which includes halting enrollment in the Phase 3 KEYFORM-008 trial. This trial was evaluating the combination of favezelimab and pembrolizumab in patients with relapsed or refractory classical Hodgkin lymphoma (cHL) whose disease had progressed after prior anti-PD-1 therapy. Patients currently enrolled in the trial will have the option to continue therapy until the study is completed. KEYFORM-008 was the only Phase 3 study in the KEYFORM program without available results. Merck’s decision to discontinue this program comes after thorough evaluation of data from the favezelimab studies and is aimed at prioritizing other candidates in its oncology pipeline. This decision is not related to safety concerns with the favezelimab-pembrolizumab combination.
Study investigators involved in these trials are being informed, and Merck advises patients to consult with their study teams and physicians regarding their next steps and treatment options. Data analyses for the Phase 3 trials are ongoing, and Merck plans to share the results with the scientific community in due course.
“Following a careful analysis of the data, the decision has been made to discontinue development of these candidates to prioritize other ongoing programs. We are grateful to all the patients, caregivers, and investigators for their many contributions that made these studies possible,” said Dr. Marjorie Green, senior vice president and head of oncology, global clinical development, Merck Research Laboratories. “We continue to pursue the most promising science with a focus on agents with the greatest potential to improve outcomes for more patients with cancer.”
Merck remains committed to advancing its diverse and innovative oncology pipeline, focusing on therapies with the highest potential to address unmet needs and improve outcomes for cancer patients worldwide. The discontinuation of these programs reflects the company’s strategy to allocate resources to candidates with stronger clinical potential, reinforcing its dedication to transformative science in oncology.
