GSK abandons chronic cough drug after $2 billion Bellus deal falters

GSK discontinued development of camlipixant for refractory chronic cough after the drug failed to show consistent efficacy across two late-stage studies, dealing a blow to the $2 billion Bellus Health acquisition.

"The aggregate data point to limited efficacy that is unlikely to transform patient care," GSK said in a statement Friday, announcing the decision to halt the refractory chronic cough program.

Camlipixant, a P2X3 receptor antagonist, met its primary endpoint in the Phase III CALM-1 study, with the 50-milligram twice-daily dose showing a statistically significant reduction in 24-hour cough frequency after 12 weeks. But the CALM-2 study, conducted in China, failed to achieve statistical significance for the same endpoint after 24 weeks. The lower 25-milligram dose did not demonstrate significant improvements in either study, and key secondary endpoints, including patient-reported outcomes, also missed predefined thresholds. The drug showed a favorable safety profile and was generally well tolerated.

GSK acquired Bellus Health in June 2023 for about $2 billion, betting on camlipixant as a potential blockbuster in a market with limited treatment options. The company had previously forecast peak annual sales of more than 2.5 billion pounds ($3.37 billion). Shares fell 3.7% in London trading Friday, trimming the stock's year-to-date gain to 3.3%.

The failure adds to investor concerns about GSK's ability to deliver on its 2031 sales target of more than 40 billion pounds, against consensus estimates of 34.88 billion pounds, according to company-compiled analyst forecasts. Jefferies analysts said the decision rules out a potential $1 billion opportunity in refractory chronic cough, while J.P. Morgan analysts said GSK would likely need to book a write-down on the program.

Camlipixant's failure continues a difficult track record for the P2X3 receptor antagonist class. Bayer abandoned its eliapixant program in 2022 over safety concerns and previously dropped filapixant due to taste-related side effects. Shionogi also appears to have stopped development of its candidate, sivopixant.

GSK will continue evaluating camlipixant in the Phase IIb BALANCE study for irritable bowel syndrome with diarrhea and mixed bowel habits, with results expected by March 2027, according to ClinicalTrials.gov.

The discontinuation removes a key pipeline asset from GSK's respiratory portfolio and raises questions about the company's deal-making strategy. Investors will watch for any impairment charge in GSK's next quarterly report and for updates on the BALANCE trial as the remaining catalyst for the Bellus acquisition.

This article is for informational purposes only and does not constitute investment advice.