FDA Approves GSK's Depimokimab for Severe Asthma with Th2 Inflammation, First Ultra-Long Acting Biologic

The FDA today approved depemokimab (Exdensur), GSK's ultra-long-acting biologic therapy, as add-on maintenance treatment for asthma with an eosinophilic phenotype (ie, type 2 inflammation) in adults and adolescents aged 12 years and older.1 This marks the first FDA approval of a biologic therapy with a 6-month dosing interval for the chronic respiratory disease.1

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“Physicians in the US now have the option to provide sustained protection from exacerbations for patients living with severe asthma with an eosinophilic phenotype in just two doses a year. Exdensur could redefine patient care and further establish the use of biologics for those who continue to experience exacerbations despite treatment,” said Kaivan Khavandi, SVP & Global Head, Respiratory, Immunology & Inflammation R&D, GSK, in a statement.1

Revolutionary Asthma Results

The approval is based on results from GSK's comprehensive SWIFT-1 and SWIFT-2 phase 3 clinical trial program. In the replicate SWIFT trials, depemokimab demonstrated compelling efficacy in patients with severe asthma characterized by elevated blood eosinophil counts.2,3 The studies enrolled 762 patients who were already receiving medium- to high-dose inhaled corticosteroids plus at least one additional controller medication but continued to experience exacerbations.2,3

Results published in The New England Journal of Medicine showed that depemokimab achieved a 54% reduction in the annual rate of clinically significant asthma exacerbations compared to placebo in a pooled analysis.2 In SWIFT-1, the annual exacerbation rate was 0.46 with depemokimab versus 1.11 with placebo (rate ratio 0.42, P <.001).2 SWIFT-2 produced similar results with rates of 0.56 versus 1.08 (rate ratio 0.52, P <.001).2

Importantly for patients and healthcare systems, depemokimab achieved a 72% reduction in severe exacerbations requiring hospitalization or emergency department visits.2 The therapy demonstrated sustained suppression of blood eosinophils, a key marker of type 2 inflammation that drives asthma attacks in more than 80% of people with severe asthma.2,3

“The struggle for people living with severe asthma is immense, with many silently enduring continued symptom recurrence and exacerbations. An innovative treatment option like Exdensur that offers the long-acting protection from exacerbations that severe asthma patients with an eosinophilic phenotype deserve, with the benefit of fewer doses, is truly welcome," Tonya Winders, President and CEO, Global Allergy & Airways Patient Platform, said.1

Novel Mechanism and Safety Profile

Depemokimab is a monoclonal antibody engineered with enhanced binding affinity and potency for interleukin-5 (IL-5), a key cytokine driving type 2 inflammation.2,3 Its extended half-life enables the unprecedented 6-month dosing interval, potentially addressing adherence challenges associated with more frequent injections.2

Across the 4 pivotal trials, depemokimab demonstrated a well-tolerated safety profile.2,3 Adverse event rates were similar between depemokimab and placebo groups in both the asthma trials (SWIFT-1: 73% vs 73%; SWIFT-2: 72% vs 78%). Fewer than 1% of patients discontinued treatment due to adverse events, and no serious adverse events were considered treatment-related by investigators.2,3

Impact on Patient Care

Type 2 inflammation affects approximately 2 million of the estimated 26 million Americans with asthma, shifting classification of the condition into the category of severe disease.4,5 Among the population with asthma, 40% reporting at least one attack annually.6

Current treatment options require dosing intervals ranging from 2 to 4 weeks. Depemokimab's twice-yearly schedule represents a paradigm shift that could improve treatment adherence and reduce the burden on both patients and healthcare systems, GSK said.1

“Current biologic treatments for asthma are often underutilised and 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 utilisation," Geoffrey Chupp, MD, Professor of Medicine, Pulmonary, Critical Care and Sleep Medicine, Yale University, said in a statement. "Exdensur could empower physicians and patients to potentially achieve their treatment goals with fewer injections."

Depemokimab is administered as a 100 mg subcutaneous injection every 26 weeks.1,2 GSK has indicated that additional studies are ongoing in other IL-5-mediated diseases, including eosinophilic granulomatosis with polyangiitis (EGPA) and hypereosinophilic syndrome (HES).

References

1. Exdensur (depemokimab) approved by US FDA for the treatment of severe asthma. News release. GSK. December 17, 2025. Accessed December 17, 2025. https://www.gsk.com/en-gb/media/press-releases/exdensur-depemokimab-approved-by-us-fda-for-the-treatment-of-severe-asthma/

2. Jackson DJ, Wechsler ME, Busse WW, et al. Twice-yearly depemokimab in severe asthma with an eosinophilic phenotype. N Engl J Med. 2024;391(24):2337-2349. doi:10.1056/NEJMoa2406673

3. Depemokimab late-breaking data presented at ERS show a 54% reduction in severe asthma exacerbations. News release. GSK. September 9, 2024. Accessed December 10, 2025. https://www.gsk.com/en-gb/media/press-releases/depemokimab-late-breaking-data-presented-at-ers-show-a-54-reduction-in-severe-asthma-exacerbations/

4. Wang E, Wechsler ME, Tran TN, et al. Characterization of severe asthma worldwide. Chest. 2020;157(4):790-804. doi:10.1016/j.chest.2019.10.053

5. Menzies-Gow A, Canonica GW, Winders TA, et al. A renewed charter: key principles to improve patient care in severe asthma. Adv Ther. 2022;39(12):5307-5326. doi:10.1007/s12325-022-02340-w

6. Mazurek JM, Syamlal G. Prevalence of asthma, asthma attacks, and emergency department visits for asthma among working adults—National Health Interview Survey, 2011–2016. MMWR Morb Mortal Wkly Rep. 2018;67(13):377-386. doi:10.15585/mmwr.mm6713a1