Merck has announced the termination of the vibostolimab and pembrolizumab coformulation arm in the Phase 3 KeyVibe-010 trial, according to a news release from the company.

The trial assessed the combination therapy's efficacy compared to KEYTRUDA alone as adjuvant treatment for patients with resected high-risk melanoma (Stage IIB-IV). The researchers said their analysis revealed that the primary endpoint of recurrence-free survival (RFS) did not meet pre-specified criteria for efficacy. Patients in the coformulation arm of the trial showed a higher discontinuation rate of all adjuvant therapy (due primarily to immune-mediated adverse events), making it unlikely for the trial to achieve a statistically significant improvement in RFS. An independent Data Monitoring Committee (DMC) recommended unblinding the study, with patients in the coformulation arm offered KEYTRUDA monotherapy going forward. Merck plans to share the data with the scientific community and regulatory agencies.

“Through our clinical development program, we continue to ask the tough questions in an effort to fully explore the potential of novel coformulations and combinations that build on the foundation of KEYTRUDA, with a goal to improve upon current standards of care and help even more patients with cancer,” Dr. Marjorie Green, senior vice president and head of oncology, global clinical development, Merck Research Laboratories, said in a news release. “We are grateful to the patients and investigators for their participation and will leverage insights from this trial as we rapidly advance our diverse pipeline of novel mechanisms, including further study of this coformulation in lung cancer.”

KEYTRUDA is approved in the U.S. for two indications in melanoma. Vibostolimab, an investigational anti-TIGIT antibody, aims to activate T-lymphocytes to combat tumor cells. Merck said that it is conducting extensive trials, including ongoing Phase 3 studies in lung cancer, with no anticipated changes based on the KeyVibe-010 findings.

Source: Merck press release. Published May 13, 2024.