Camlipixant, which GSK picked up in its $2 billion buyout of Bellus Health in April 2023, “is unlikely to transform patient care,” the pharma said.
GSK will no longer invest in the development of camlipixant in chronic cough after a disappointing late-stage performance.
The pharma had been running the Phase 3 CALM-1 and CALM-2 trials, which tested a 52-week and 24-week course of camlipixant, respectively. CALM-1 met a primary endpoint, GSK said on Friday, with a 50-mg dose significantly lowering 24-hour cough frequency at 12 weeks versus placebo.
Camlipixant failed CALM-2, however, with no significant decrease in cough frequency occurring. Both trials missed key secondary endpoints, according to GSK.
With this efficacy profile, camlipixant “is unlikely to transform patient care,” GSK said in its release, adding that it will no longer develop the drug for refractory chronic cough (RCC). The pharma will continue to study the drug for irritable bowel syndrome, for which it is in mid-stage development.
Camlipixant, an orally available blocker of the P2X3 receptor, was originally discovered and developed by Bellus Health, which GSK acquired in April 2023 for $2 billion.
P2X3 receptors are expressed by nerves on airways, which are present at a much higher density than usual in patients with refractory chronic cough. By blocking the P2X3 cascade, camlipixant is supposed to work by normalizing cough reflex and frequency.
At the time of the acquisition, GSK was in a cough contest with Merck, which was developing another P2X3 antagonist called gefapixant—a drug that had already been rebuffed by the FDA once. In January 2022, the agency had rejected gefapixant’s application in refractory chronic cough for issues unrelated to safety, though the pharma at the time did not provide further details.
In December 2023, months after GSK’s buyout of Bellus, Merck’s gefapixant again failed to secure a U.S. approval, with the FDA saying the drug package “did not meet substantial evidence of effectiveness.” Currently, Merck sells the drug as Lyfnua in several European countries and Japan.
For GSK, the decision to discontinue camlipixant in RCC follows the termination of its partnership with Alector, effective Jan. 2, 2027. The companies first linked up in July 2021 to advance two antibodies for neurodegenerative conditions. Both assets failed in the clinic, leading to the pharma’s decision to abandon Alector. At the time, GSK paid $700 million upfront and earmarked up to $1.5 billion in possible milestones for the biotech.
