GSK has discontinued development of the once promising P2X3 antagonist, camlipixant, after determining that the cough drug's limited efficacy demonstrated in a pair of trials is “unlikely to transform patient care.”
The oral tablet was being tested for the treatment of refractory chronic cough, an under-recognised disease with limited treatment options. While the CALM-1 trial met its primary endpoint with camlipixant 50mg twice daily showing statistically significant reductions in 24-hour cough frequency versus placebo at week 12, CALM-2 did not reach statistical significance in the same primary endpoint with 50mg twice daily at week 24. Camlipixant 25mg twice daily did not reach statistical significance in either study. Key secondary endpoints did not meet target thresholds in either study.
GSK picked up the experimental cough drug in 2023 when it paid $2 billion to acquire Bellus Health. At the time, the potential best-in-class drug was in phase 3 development for the first-line treatment of adult patients with refractory chronic cough and GSK had hoped to add it to its portfolio of respiratory drugs.