GSK (LSE:GSK) said its CALM-1 and CALM-2 phase III trials produced mixed results for camlipixant, a P2X3 receptor antagonist tested in adults with refractory chronic cough.
Refractory chronic cough is a complex, under-recognised condition with treatment options, according to GSK.
CALM-1 met its primary endpoint, with the 50mg twice-daily dose showing a statistically significant reduction in 24-hour cough frequency versus placebo at 12 weeks.
CALM-2 did not reach statistical significance on the same measure at 24 weeks, and the lower 25mg dose failed in both studies.
Key secondary endpoints, including a Chronic Cough Diary measure, missed target thresholds across both trials.
Treatment-related adverse events were similar between camlipixant and placebo groups.
GSK said the aggregate data show efficacy unlikely to transform patient care, and it will not progress the drug further in this indication.
Results from the CALM programme will be submitted for future publication to inform scientific understanding of the disease.
Camlipixant's development continues elsewhere: the phase IIb BALANCE trial is still evaluating the compound in irritable bowel syndrome with diarrhoea and mixed-type irritable bowel syndrome.
News Intelligence what this means for the company
GSK is discontinuing camlipixant for refractory chronic cough after one of two pivotal phase III trials failed to meet its primary endpoint; the successful CALM-1 trial showed efficacy with the 50mg dose, but CALM-2 missed statistical significance at 24 weeks, and key secondary endpoints flopped in both studies. GSK judged the aggregate data insufficient to transform patient care and halted development in this indication, though the compound continues evaluation in irritable bowel syndrome.
This is a single-asset setback in GSK's pipeline rather than a portfolio-level concern; the company has a $40bn+ revenue base and multiple late-stage programmes (dostarlimab label expansions, bepirovirsen PDUFA October 2026, Nuvalent acquisition integration). The camlipixant failure removes one potential future revenue stream but does not materially alter GSK's near-term catalysts or financial trajectory.
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