After successfully completing two trials, SWIFT-1 and SWIFT-2, for its long-acting asthma drug depemokimab, GSK has now shared results for its Phase 3 trial. These trials demonstrated the treatment’s ability to reduce the number of asthma attacks experienced by participants by half, achieving the primary endpoint of the study.
Although it was announced in May that the study had met its primary endpoint, the full details were only recently revealed at the European Respiratory Society International Conference in Vienna. Compared to a placebo, the treatment reduced asthma exacerbations by 54% over 52 weeks in 760 adults and adolescents with severe asthma and type 2 inflammation.
While some secondary endpoints, such as improvements in quality of life, lung function, and asthma control, were not met by depemokimab, the drug did succeed in other areas. A pooled analysis showed that the monoclonal antibody reduced clinically significant exacerbations—those resulting in hospitalization or emergency department visits—by 72%.
Despite the secondary endpoint misses, Khavandi confirmed that GSK will proceed with its plans for depemokimab without changing its strategy. While the company has not specified a timeline for regulatory submission, it has indicated that it will communicate with global health authorities as soon as possible.
Depemokimab works by blocking human interleukin-5 (IL-5) from binding to its receptor, a key protein involved in asthma with type 2 inflammation. In this condition, eosinophils—a type of white blood cell—are elevated. A significant number of patients with severe eosinophilic asthma must discontinue their treatment after a year if they are on short-acting biologics, creating a gap that GSK’s depemokimab can fill as a twice-yearly injection. If approved, it would become the first ultra-long-acting biologic treatment.
In terms of safety, no deaths or serious adverse events (AEs) were considered related to the treatment. In the SWIFT-1 trial, the proportion of adverse events was comparable between the depemokimab and placebo groups, both at 73%. In SWIFT-2, the rate fell to 72% for depemokimab and rose to 78% for the placebo group.
Based on the treatment’s performance, GSK is positioning depemokimab as one of its 12 potential blockbuster launches in the coming years, with peak annual sales projected to reach $3.9 billion once approved.
