GSK’s Exdensur wins US FDA approval as twice-yearly biologic for severe eosinophilic asthma

Edited by Robert McTiernan··2 min read

GSK plc revealed US FDA approval for Exdensur (depemokimab-ulaa) as an add-on maintenance treatment for patients aged 12 years and older with severe asthma characterized by an eosinophilic phenotype. The market nod is the first for an ultra-long-acting biologic with a twice-yearly dosing regimen in this setting.

The decision is backed by the Phase 3 SWIFT-1 and SWIFT-2 clinical programs, in which twice-annual depemokimab demonstrated substantial reductions in annualized asthma exacerbation rates compared with placebo plus standard of care. In these trials, treatment with Exdensur cut exacerbations by 58% in SWIFT-1 and 48% in SWIFT-2 over 52 weeks, and a pooled analysis showed a 72% reduction in clinically significant exacerbations requiring hospital care or emergency department visits versus placebo.

IL-5 and asthma

Exdensur is an anti-IL-5 monoclonal antibody developed in-house by GSK. Interleukin-5 (IL-5) is a cytokine central to the development, activation, and survival of eosinophils—a type of white blood cell implicated in airway inflammation and hyperresponsiveness in asthma, particularly in the eosinophilic phenotype. Elevated IL-5 levels and eosinophil counts are strongly associated with asthma severity and exacerbations. Targeting IL-5 or its receptor (IL-5R) disrupts this pathway, reducing eosinophilic inflammation and its downstream effects on airway function and remodeling.

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GSK’s own mepolizumab (Nucala) was the first IL-5 antagonist monoclonal antibody approved by the FDA for maintenance treatment of patients with severe asthma with an eosinophilic phenotype, followed by Teva’s reslizumab (Cinqair) and AstraZeneca’s benralizumab (Fasenra). All three require dosing once every four weeks. Exdensur’s approval looks set to offer a new benchmark, the extended dosing interval supporting improved patient adherence and convenience compared with more frequent biologic injections.

An estimated 2 million Americans live with severe asthma, and roughly half continue to experience frequent exacerbations and hospitalizations despite current care — underscoring an ongoing unmet need in this population.

Exdensur has also recently secured marketing authorization in the UK, and a positive opinion from the European Medicines Agency’s CHMP signals likely EU approval in early 2026.