Merck discontinues vibostolimab-Keytruda combination arm of Phase 3 trial

Merck announced the discontinuation of the vibostolimab and pembrolizumab coformulation arm of the Phase 3 KeyVibe-010 trial. The trial is evaluating the investigational coformulation of vibostolimab, an anti-TIGIT antibody, and pembrolizumab, or Keytruda, Merck’s anti-PD-1 therapy, compared to Keytruda alone, as adjuvant treatment for patients with resected high-risk melanoma. Data showed that the primary endpoint of recurrence-free survival met the pre-specified futility criteria. A higher rate of discontinuation of all adjuvant therapy by patients in the coformulation arm versus the Keytruda-only arm, primarily due to immune-mediated adverse experiences, rendered it highly unlikely that the trial could achieve a statistically significant improvement in RFS. Merck is unblinding the study and recommends that patients receiving the vibostolimab and pembrolizumab coformulation be offered the option to be treated with Keytruda monotherapy. Merck has a clinical development program evaluating the safety and efficacy of the vibostolimab and pembrolizumab coformulation alone and in combination with other agents in over 3,000 patients.