Merck Announces Discontinuation of Vibostolimab (Anti-TIGIT) and Favezelimab (Anti-LAG-3) Development Programs

December 16,MSD(MRK.US) announced the termination of the development of the anti-TIGIT antibody Vibostolimab and the anti-LAG-3 antibody Favezelimab.

Vibostolimab (MK-7684) restores the tumor-killing activity of T cells by blocking the binding of the TIGIT receptor to its ligands (CD112 and CD155). Favezelimab (MK-4280) restores T cell effector function by blocking the LAG-3 receptor from binding to its major ligand, the major histocompatibility complex (MHC) class II molecule.

In the pre-planned analysis, both the KeyVibe-003 study and the KeyVibe-007 study met the pre-specified futility criteria for the primary endpoint of OS.

MSD stated that more immune-related adverse events occurred in the fixed-dose combination therapy group than in the pembrolizumab monotherapy group.

Based on all data from the existing KeyVibe series of studies, MSD has decided to terminate the Phase III KeyVibe-006 study and other clinical studies of vibostolimab.

In addition, based on all existing clinical data, MSD has also decided to terminate the clinical development program of Favezelimab and will halt the Phase III KEYFORM-008 study. Patients already enrolled can continue to receive treatment until the study is completed. The KEYFORM-008 study is the only Phase III study in the KEYFORM clinical development program that has not yet yielded results. MSD emphasized that this decision to terminate is unrelated to the safety of MK-4280A.

Editorial Responsibility: Guo Mingyu