Merck, a global biopharmaceutical company developing medicines and vaccines for many of the world’s most challenging diseases, announced the efficacy results from Phase 3 trials evaluating gefapixant (MK-7264), a selective P2X3 receptor antagonist, for the treatment of refractory or unexplained chronic cough. The high (45 mg) dose met the primary efficacy endpoints, whereas the 15 mg dose failed.
Although the detailed findings from these trials are yet to be shared, some concerns about the tolerability of a 45 mg dose of gefapixant exist. In fact, Phase 2b trials demonstrated that high-dose (50 mg) gefapixant was associated with some unpleasant taste effects leading to some discontinuations. This information could be exploited by other companies working on P2X3 antagonists (Bellus Health, Bayer, Shionogi, Asana BioSciences) in order to develop a more potent, selective and tolerable alternative.