GSK Gets FDA Approval for New Severe Asthma Drug With a Dosing Advantage
Severe asthma is already treatable with a monthly injectable GSK drug, the blockbuster product Nucala. A new FDA approval gives the drugmaker the opportunity to reach patients with a different biologic medication that treats asthma in a similar way to Nucala, but with just two shots a year.
The FDA late Tuesday approved the new GSK drug, depemokimab, as an add-on maintenance treatment for severe asthma — disease that requires medium-to-high doses of the inhaled corticosteroids that are already a standard treatment plus a second therapy to keep asthma from becoming uncontrolled. FDA approval of depemokimab makes it a new patient option for that second therapy. GSK will commercialize this new asthma product under the brand name Exdensur.
Exdensur’s FDA approval specifically covers patients age 12 and older whose asthma is driven by eosinophils, a type of white blood cell. High levels of these cells can lead to what’s called type 2 inflammation. An estimated 80% of patients with severe asthma have high levels of eosinophils. Nucala and Exdensur are both antibodies designed to bind to and inhibit IL-5, a signaling protein that activates eosinophils. The key difference is that Exdensur is an ultra-long-acting antibody whose extended half-life enables twice-yearly dosing. This drug is not indicated for treating acute asthma attacks.
GSK’s FDA submission was based on two placebo-controlled Phase 3 clinical trials that evaluated Exdensur alongside standard corticosteroids. The main goal of both 52-week studies was to measure the annualized rate of clinically significant exacerbations, or asthma attacks. Results show exacerbations were reduced by 58% and 48% respectively. On secondary trial measures, results show numerically fewer exacerbations requiring hospitalization or emergency room visits compared to placebo. The study drug was well tolerated and the rate and severity of side effects were similar across the Exdensur and placebo arms. Detailed results were presented last year during the European Respiratory Society International Conference and published in the New England Journal of Medicine.
GSK points to published research estimating that 2 million Americans with severe asthma continue to experience frequent exacerbations that may require hospitalization or emergency room visits. Despite the availability of biologic drugs, such as Nucala, research also shows underuse of these drugs. Only 20% of asthma patients eligible for treatment with a biologic drug receive one. GSK notes that additional research indicates longer dosing intervals increase the likelihood of patients considering a biologic medication. According to Dr. Geoffrey Chupp, professor of medicine, pulmonary, critical care and sleep Medicine at Yale University, frequent injections can be inconvenient for many patients and lead to inconsistent use.
“There is clearly an opportunity to provide a longer duration of protection from exacerbations between injections for severe asthma patients that reduces the frequency of doses and may improve overall health care utilization,” Chupp said in GSK’s approval announcement. “Exdensur could empower physicians and patients to potentially achieve their treatment goals with fewer injections.”
GSK’s top respiratory product is Trelegy Elipta, which has approvals in both asthma and chronic obstructive pulmonary disease (COPD). Nucala, first approved in 2015 for severe asthma, added COPD to its list of indications this past spring. This type 2 inflammation-reducing drug generated £1.7 billion (about $2.2 billion) in revenue last year across its approved indications. AstraZeneca addresses type 2 inflammation with Fasenra, an antibody designed to block the IL-5 receptor. This blockbuster product, administered monthly for the first three doses and then every eight weeks afterward, was approved for severe eosinophilic asthma in 2017.
AstraZeneca is also partnered with Amgen on the commercialization of the Tezspire, a once-monthly injectable antibody drug that blocks a different target, the signaling protein TSLP. This drug was initially approved for severe asthma in 2021. Severe asthma is one of the approved indications for Dupixent, the IL-13- and IL-4-blocking antibody drug that is a blockbuster seller for Sanofi and Regeneron Pharmaceuticals. Dupixent is administered by injection every two or four weeks depending on the indication.
The clinical trial program for Exdensur includes a Phase 3 study evaluating the drug in patients who switched from Nucala or Fasenra. But GSK has broader plans for its new asthma drug. Exdensur is under FDA review for chronic rhinosinusitis with nasal polyps (CRSwNP). Phase 3 studies are underway in eosinophilic granulomatosis with polyangiitis, hypereosinophilic syndrome, and COPD.
GSK has not yet disclosed Exdensur’s price. In October, during the company’s conference call to discuss third quarter 2025 financial results, Chief Commercial Officer Luke Miels said the asthma drug is expected to launch in the U.S. in early 2026. Regulatory submissions for Exdensur are under review at agencies around the world. Last week, a key European Medicines Agency committee issued a positive opinion for the drug; a regulatory decision in Europe is expected in the first quarter of 2026.
Photo: Jackie Niam, Getty Images
