GSK wins FDA approval for new severe asthma drug with dosing advantages
Severe asthma can already be treated with monthly injections of GlaxoSmithKline's drug, blockbuster Nucala. A new FDA approval gives the drugmaker a chance to offer patients another biologic drug that treats asthma in a similar way to Nucala, but in just two injections a year.
The FDA late Tuesday approved GlaxoSmithKline's new drug depemokimab as an add-on maintenance treatment for severe asthma. The disease requires moderate to high doses of inhaled corticosteroids, already a standard treatment, plus a second treatment to prevent asthma from getting out of control. The FDA's approval of depemokimab makes it a new patient option for second therapy. GlaxoSmithKline will commercialize the new asthma product under the brand name Exdensur.
Exdensur is FDA-approved specifically to cover patients ages 12 and older with asthma caused by eosinophils, a type of white blood cell. High levels of these cells lead to what is called type 2 inflammation. An estimated 80% of people with severe asthma have high eosinophil levels. Nucala and Exdensur are both antibodies designed to bind to and inhibit IL-5, a signaling protein that activates eosinophils. The main difference is that Exdensur is an ultra-long-acting antibody with a longer half-life and can be administered twice a year. This medicine is not used to treat acute asthma attacks.
GSK's submission to the FDA was based on two placebo-controlled Phase 3 clinical trials that evaluated Exdensur versus standard corticosteroids. The primary objective of both 52-week studies was to measure the annualized rate of clinically significant exacerbations or asthma exacerbations. The results showed that exacerbations were reduced by 58% and 48% respectively. Among secondary trial measures, results showed fewer exacerbations requiring hospitalization or emergency room visits compared with placebo. The study drug was well tolerated, with similar incidence and severity of side effects in the Exdensur and placebo groups. Detailed results were presented last year at the European Respiratory Society International Conference and published in the New England Journal of Medicine.
GSK noted that published studies estimate that 2 million Americans with severe asthma continue to experience frequent exacerbations that may require hospitalization or emergency room visits. Although biologic drugs such as Nucala are available, research also shows that these drugs are underused. Only 20% of asthma patients who are eligible for biologic therapy receive it. GlaxoSmithKline noted that additional research suggests that longer dosing intervals increase the likelihood that patients will consider biologic drugs. Frequent injections can be inconvenient for many patients and lead to inconsistent use, said Dr. Geoffrey Chupp, professor of medicine, pulmonary, critical care and sleep medicine at Yale University.
“There is a clear opportunity to provide patients with severe asthma with longer intervals between injections to prevent exacerbations, thereby reducing medication frequency and potentially improving overall healthcare utilization,” Chupp said in GSK's approval announcement. “Exdensur can help physicians and patients achieve treatment goals with fewer injections.”
GSK's top respiratory product is Trelegy Elipta, which is approved to treat asthma and chronic obstructive pulmonary disease (COPD). Nucala was first approved to treat severe asthma in 2015, and this spring added chronic obstructive pulmonary disease (COPD) to its list of indications. The type 2 inflammation-reducing drug generated 1.7 billion pounds ($2.2 billion) in revenue last year across its approved indications. AstraZeneca treats type 2 inflammation with Fasenra, an antibody designed to block the IL-5 receptor. The blockbuster product, which is administered as monthly injections for the first three doses and then every eight weeks, was approved in 2017 to treat severe eosinophilic asthma.
AstraZeneca is also working with Amgen to commercialize Tezspire, a once-monthly injection of an antibody drug that blocks a different target, the signaling protein TSLP. The drug was originally approved in 2021 to treat severe asthma. Severe asthma is one of the approved indications for Dupixent, an antibody drug that blocks IL-13 and IL-4 and is a best-selling product from Sanofi and Regeneron Pharmaceuticals. Dupixent is administered as an injection every two or four weeks, depending on the indication.
Exdensur's clinical trial plan includes a Phase 3 study evaluating the drug in patients switching from Nucala or Fasenra. But GlaxoSmithKline has broader plans for its new asthma drug. Exdensur is under FDA review for chronic rhinosinusitis with nasal polyps (CRSwNP). Phase 3 studies are ongoing in eosinophilic granulomatosis with polyangiitis, eosinophilic syndrome and chronic obstructive pulmonary disease (COPD).
GSK has not revealed the price of Exdensur. In October, during the company's conference call to discuss third-quarter 2025 financial results, Chief Commercial Officer Luke Miels said the asthma drug was expected to be available in the United States in early 2026. Agencies around the world are reviewing Exdensur's regulatory applications. Last week, a key European Medicines Agency committee issued a positive opinion on the drug; Europe is expected to make a regulatory decision in the first quarter of 2026.
Photo: Jackie Niamh, Getty Images
