GSK Drops $2B Cough Drug After Trial Split

GSK is walking away from camlipixant in chronic cough, the drug it paid $2 billion to get when it bought Bellus Health in April 2023.

The compound split its two pivotal trials. CALM-1 hit its primary endpoint, with the 50-mg dose cutting 24-hour cough frequency versus placebo at week 12. CALM-2 didn’t, and both studies missed key secondary endpoints. GSK’s own verdict: camlipixant “is unlikely to transform patient care” in refractory chronic cough. That’s a company writing off its own $2 billion bet in one sentence.

I’ve read a lot of sponsor statements dressing up a miss as a strategic pivot. This one doesn’t bother. GSK isn’t spinning a resubmission path or a subgroup analysis, it’s just stopping.

Camlipixant was supposed to be GSK’s answer to Merck’s gefapixant, another P2X3 blocker for the same indication. Merck’s drug got rejected twice, most recently when the FDA said in December 2023 the application “did not meet substantial evidence of effectiveness.” Two sponsors, two P2X3 antagonists, zero U.S. approvals in refractory chronic cough. That’s not a company-specific stumble, that’s the mechanism itself struggling to clear FDA’s efficacy bar in this population.

Camlipixant isn’t dead everywhere. GSK is keeping it alive in irritable bowel syndrome, where it’s still in the Phase 2b BALANCE trial. This is also GSK’s second scrapped asset in short order, following the January 2027 wind-down of its Alector antibody partnership, another deal where the clinic didn’t cooperate.

— Rebecca Lauren