GSK’s Long-Acting Asthma Drug Hits Primary Endpoint in Phase III Trials

Pictured: GSK's headquarters building in West Lond

Pictured: GSK’s headquarters building in West Lond

Participants experienced fewer asthma attacks when receiving the antibody every six months, GSK said Tuesday, positioning the company to file for approval of the potential blockbuster.

Pictured: GSK’s headquarters building in West London/iStock/Tati Campelo

GSK said Tuesday an asthma drug candidate that is given every six months improved outcomes in a pair of pivotal Phase III trials, teeing up filings for approval of a molecule tipped to generate blockbuster sales.

The studies compared GSK’s ultra-long-acting anti-IL-5 monoclonal antibody depemokimab to placebo in adults and adolescents with severe asthma with Type II inflammation characterized by blood eosinophil count. Over 52 weeks, depemokimab significantly reduced asthma attacks, causing the studies to meet their primary endpoints. GSK plans to use the data to seek approval in markets around the world.

GSK already sells the anti-IL-5 antibody Nucala (mepolizumab) that is injected every four weeks. While Nucala is a blockbuster, generating 1.7 billion pounds ($2.2 billion) last year, GSK contends the dosing schedule for depemokimab can unlock additional sales. The company increased its depemokimab sales forecast to more than 3 billion pounds last year, up from under 2 billion pounds in its earlier prediction.

Management’s confidence in depemokimab is underpinned by surveys of physicians and patients. The surveys found physicians have positive views of depemokimab, GSK said at its respiratory diseases event in November 2023. Physicians told GSK they are interested in switching patients to depemokimab and prescribing the antibody to people with asthma who are yet to try a biologic therapy. AstraZeneca and Teva Pharmaceuticals sell IL-5 asthma drugs but both are given far more frequently than depemokimab.

The Phase III asthma results are part of a series of upcoming pivotal readouts for depemokimab. Building on its experience with Nucala, GSK advanced depemokimab into pivotal trials in four indications on the strength of Phase I data and pharmacokinetic and pharmacodynamic modeling.

GSK expects to report Phase III data in chronic rhinosinusitis with nasal polyps this year and is aiming to file for approval in that indication and asthma by the end of 2024. Phase III eosinophilic granulomatosis with polyangiitis results are due next year. The decision to run Phase III trials in parallel means GSK could expand the label of depemokimab to cover multiple indications much faster than it did for Nucala.

“We’ve just taken a more proactive approach to life cycle management. It’s going to take about two years from the initial indication in eosinophilic asthma right through to [hypereosinophilic syndrome],” Luke Miels, chief commercial officer at GSK, said at an event in November 2023. “We’ll be able to interact around the label with different physician groups who could influence the usage of this product.”

Nick Paul Taylor is a freelance pharmaceutical and biotech writer based in London. He can be reached on LinkedIn.