US FDA Grants Approval to Exdensur, ultra-long acting biologic for Severe Eosinophilic Asthma

GSK announced that the US Food and Drug Administration (FDA) has approved Exdensur (depemokimab-ulaa) as an add-on maintenance treatment for adults and adolescents aged 12 years and older with severe asthma characterized by an eosinophilic phenotype.

Exdensur stands out as the first ultra-long-acting biologic therapy for severe asthma, designed for twice-yearly dosing, offering patients a more convenient treatment schedule compared with currently available biologics.

Clinical evidence supporting approval

The FDA’s decision is supported by data from Phase III SWIFT-1 and SWIFT-2 clinical trials, which evaluated depemokimab in patients whose asthma remained uncontrolled despite standard care. Across both studies, patients receiving depemokimab experienced significant and sustained reductions in annualized asthma exacerbation rates compared with placebo, showing a 58% reduction in SWIFT-1 and a 48% reduction in SWIFT-2 over a 52-week period.

Depemokimab also demonstrated benefits in reducing severe exacerbations requiring hospitalization or emergency department (ED) visits. In both studies, only a small percentage of patients treated with depemokimab required emergency care compared with those on placebo. A pooled analysis of both trials revealed a 72% decrease in the annualized rate of exacerbations leading to hospitalizations or ED visits.

Across all evaluated safety parameters, the therapy was generally well-tolerated, with side effect rates comparable to placebo.

Redefining asthma care with long-acting therapy

Depemokimab has been specifically developed with an extended half-life, enabling prolonged inhibition of type 2 inflammation—one of the key biological drivers of severe eosinophilic asthma. With twice-yearly administration, Exdensur aims to simplify disease management, improve adherence, and reduce healthcare system pressures caused by frequent exacerbations and hospital visits.

In the United States, approximately two million individuals are affected by severe asthma. Despite the availability of biologic therapies, half of these patients continue to experience frequent flare-ups, leading to hospitalization and significant healthcare costs. Furthermore, only a small proportion of eligible patients (around 20%) currently receive biologic treatments. Longer dosing intervals—such as those offered by Exdensur, may improve acceptance and accessibility, as both patients and healthcare providers express strong interest in extended-interval options.

Understanding severe asthma

Severe asthma is defined as a form of the disease that requires medium- to high-dose inhaled corticosteroids combined with an additional therapy (such as systemic corticosteroids or biologics) to remain controlled, or that remains uncontrolled despite current therapy. Around 80% of patients with severe asthma have type 2 inflammation, a condition marked by elevated eosinophil levels, which drive airway inflammation and worsening symptoms.

About Exdensur (depemokimab)

Exdensur represents a new generation of long-acting biologics targeting diseases associated with type 2 inflammation, including severe eosinophilic asthma. Its distinct pharmacokinetic design enables durable disease control with twice-yearly dosing, offering the potential to improve treatment adherence and long-term patient outcomes.