GSK plc said on July 17, 2026 [1], that it is stopping the development of camlipixant, an experimental drug for refractory chronic cough [1], [2].
The decision removes a potential therapeutic option for patients suffering from persistent coughs that do not respond to standard treatments. This failure represents a significant setback for the company's respiratory pipeline and the broader effort to target P2X3 receptors.
Camlipixant was designed as a P2X3 receptor antagonist [2]. The drug underwent rigorous testing in two late-stage Phase III trials, known as CALM-1 and CALM-2 [1], [3]. The company said the treatment failed to meet key efficacy goals across these trials [1], [2].
During the clinical evaluation, researchers tested two specific dosage levels: 50 mg and 25 mg administered twice daily [2]. Despite these variations in dosing, the results did not satisfy the primary endpoints required to move toward regulatory approval [1], [2].
GSK, headquartered in the United Kingdom, had positioned the drug as a primary solution for refractory chronic cough [1], [2]. The discontinuation follows the analysis of data from the CALM trials, which indicated the drug did not provide the necessary clinical benefit over the control groups [1], [3].
While the company did not provide a detailed breakdown of the trial failures, the discontinuation of the program is final [3]. The loss of the candidate leaves a gap in the market for specialized chronic cough medications, a condition that often lacks targeted pharmaceutical interventions.
“The drug failed to meet key efficacy goals in two late-stage (Phase III) trials”
The failure of camlipixant highlights the difficulty of developing targeted therapies for refractory chronic cough, a condition with high unmet medical needs. By failing in Phase III, the drug's inability to demonstrate efficacy at both 25 mg and 50 mg doses suggests that the P2X3 receptor pathway may be more complex to modulate than previously anticipated, potentially impacting how other biotech firms approach similar receptor antagonists.
