Merck (NYSE: MRK) has announced the discontinuation of the clinical development programs for vibostolimab and favezelimab, two investigational cancer therapies. The decision follows a review of data from Phase 3 trials that failed to meet pre-specified futility criteria for overall survival.
The KeyVibe program, which was evaluating vibostolimab in combination with pembrolizumab (Keytruda) for the treatment of non-small cell lung cancer (NSCLC), has been terminated. This includes the Phase 3 KeyVibe-003 and KeyVibe-007 trials, which assessed the fixed-dose combination of vibostolimab and pembrolizumab in patients with NSCLC. An independent Data Monitoring Committee (DMC) recommended the discontinuation based on a pre-planned analysis indicating that the trials were unlikely to meet the primary endpoint of overall survival.
KeyVibe Program Details
KeyVibe-003 was a randomized, double-blind Phase 3 trial (NCT04738487) comparing the fixed-dose combination of vibostolimab and pembrolizumab to pembrolizumab alone as a first-line treatment for patients with PD-L1 positive metastatic NSCLC. The primary endpoint was overall survival (OS) in participants with PD-L1 TPS ≥50%. The trial enrolled 1,264 patients.
KeyVibe-007 was a randomized, double-blind Phase 3 trial (NCT05226598) evaluating the fixed-dose combination of vibostolimab and pembrolizumab with chemotherapy in treatment-naïve patients with metastatic NSCLC. The primary endpoint was OS in participants with PD-L1 TPS ≥1%. The trial enrolled 739 patients.
In addition to KeyVibe-003 and KeyVibe-007, Merck has also decided to discontinue the Phase 3 KeyVibe-006 trial (NCT05298423), which was evaluating the fixed-dose combination of vibostolimab and pembrolizumab with concurrent chemoradiotherapy in patients with stage III NSCLC.
KEYFORM Program Halted
Separately, Merck has decided to end the favezelimab clinical development program. This decision impacts the Phase 3 KEYFORM-008 trial (NCT05508867), which was evaluating the fixed-dose combination of favezelimab and pembrolizumab in patients with relapsed or refractory classical Hodgkin lymphoma (cHL) whose disease has progressed following prior anti-PD-1 therapy. Patients currently enrolled in the trial may continue on therapy until study completion.
The decision to discontinue the favezelimab program was made after a thorough evaluation of data from the favezelimab clinical program. Merck will prioritize the development of other candidates in its oncology pipeline. The company emphasized that this decision was not based on any safety concerns.
Prioritizing Promising Science
"Following a careful analysis of the data, the decision has been made to discontinue development of these candidates to prioritize other ongoing programs," 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 is informing study investigators and advising patients to speak with their study team and physician regarding next steps and treatment options. Data analyses for the Phase 3 trials are ongoing, and the results will be shared with the scientific community.
