GSK announced on July 17 that it will stop investing in the development of camlipixant for chronic cough following disappointing late-stage clinical trial results.
The company had been conducting two Phase 3 trials, CALM-1 and CALM-2, to test the effectiveness of camlipixant. According to GSK, CALM-1 met its primary endpoint by showing that a 50-mg dose significantly reduced 24-hour cough frequency at 12 weeks compared to placebo. However, camlipixant failed in the CALM-2 trial, with no significant decrease in cough frequency observed. Both studies also missed key secondary endpoints.
GSK said that with this efficacy profile, camlipixant “is unlikely to transform patient care,” and confirmed it will discontinue development of the drug for refractory chronic cough. The company stated it will continue studying camlipixant for irritable bowel syndrome, where it is currently in mid-stage development.
Camlipixant is an orally available blocker of the P2X3 receptor and was originally discovered and developed by Bellus Health. GSK acquired Bellus Health in April 2023 for $2 billion as part of its efforts to compete with Merck in the chronic cough market. At that time, Merck was developing another P2X3 antagonist called gefapixant but faced regulatory setbacks from the U.S. Food and Drug Administration (FDA). In January 2022, gefapixant’s application was rejected due to issues unrelated to safety; later in December 2023, another FDA review concluded that evidence of effectiveness was insufficient for approval. Gefapixant is currently sold as Lyfnua in several European countries and Japan.
The decision regarding camlipixant comes after GSK ended its partnership with Alector effective Jan. 2, 2027. The collaboration began in July 2021 aiming to develop antibodies for neurodegenerative conditions but ended after both assets failed clinical trials.
