Depemokimab Shows Sustained Efficacy, Safety in Asthma for Up to 2 Years

For individuals grappling with severe asthma, a novel long-term study offers encouraging news regarding depemokimab, an investigational biologic therapy. Data presented this week at the American Academy of Allergy, Asthma & Immunology Annual Meeting demonstrate sustained reductions in asthma exacerbations over a two-year period, bolstering confidence in the drug’s potential as a maintenance treatment. The findings are particularly noteworthy given the December 2025 FDA approval of depemokimab (Exdensur, GSK) for severe eosinophilic asthma in patients aged 12 and older.

The study, an open-label extension of earlier trials known as SWIFT-1 and SWIFT-2, tracked 629 patients with type 2 asthma. Participants either continued receiving depemokimab, administered via subcutaneous injection twice yearly, or transitioned from a placebo to the active drug. Researchers focused on the annualized rate of asthma exacerbations – sudden worsening of symptoms requiring intervention – as a key measure of efficacy and safety.

Long-Term Efficacy and Safety Profile

The results revealed a consistently low annualized exacerbation rate among those who continued depemokimab treatment, reaching 0.55 events per year at the two-year mark. Importantly, patients who switched from placebo to depemokimab also experienced a significant decrease in exacerbations, falling from a rate of 1.12 in year one to 0.58 in year two. This suggests a sustained benefit even after initiating treatment later in the course of the disease. The study’s findings are detailed in a poster presentation at the AAAAI meeting, as reported by Healio.

Michael E. Wechsler, MD, professor of medicine at National Jewish Health, emphasized the reassuring nature of these long-term data. “These findings will provide reassurance to practicing clinicians that this novel ultra-long-acting anti-IL5 agent has sustained efficacy and safety and there should not be concerns regarding long-term use,” he told Healio.

Understanding Depemokimab and its Mechanism

Depemokimab targets interleukin-5 (IL-5), a key protein involved in the development and function of eosinophils, a type of white blood cell that plays a central role in the inflammatory processes driving eosinophilic asthma. Unlike some other biologics targeting IL-5, depemokimab is designed to be an ultra-long-acting therapy, potentially allowing for less frequent dosing – in this case, every six months. This could significantly improve convenience and adherence for patients. The drug’s enhanced binding affinity for IL-5 is thought to contribute to its extended duration of action, as described in a recent publication in the New England Journal of Medicine.

Study Details and Participant Characteristics

The AGILE study involved a diverse group of patients with type 2 asthma, characterized by elevated blood eosinophil levels – a marker of inflammation. Specifically, participants had either a blood eosinophil count of at least 150 cells/μL at the start of the SWIFT-1/-2 trials or a count of at least 300 cells/μL in the year prior. The study population was predominantly white (77-80% in both groups), with a signify age of around 53-55 years, and a majority were female (59-61%). A high proportion of participants – over 90% in both groups – completed the full two years of treatment and study participation.

Safety and Adverse Events

The study reported a generally favorable safety profile for depemokimab. The proportion of patients experiencing any adverse event was comparable between those continuing depemokimab and those switching from placebo (71% vs. 70%), as were the rates of serious adverse events (9% in both groups). Critically, no fatal or treatment-related serious adverse events were observed.

Adverse events related to the study treatment were infrequent, affecting only 4% of those continuing depemokimab and 2% of those switching from placebo. The most commonly reported adverse events – nasopharyngitis (common cold), upper respiratory tract infection, and COVID-19 – were similar to those observed in previous phase 3 trials of depemokimab, including studies in patients with chronic rhinosinusitis with nasal polyps (CRSwNP). A little percentage of patients tested positive for anti-drug antibodies (ADA), but this did not appear to affect the drug’s safety or efficacy.

Implications for Asthma Management

The AGILE study reinforces the potential of depemokimab as a valuable addition to the treatment armamentarium for severe eosinophilic asthma. The sustained reduction in exacerbations, coupled with a manageable safety profile, suggests that the drug could improve quality of life and reduce healthcare utilization for patients with this challenging condition. The twice-yearly dosing schedule also offers a significant convenience advantage over other biologics that require more frequent administration.

However, it’s crucial to note that this study was an open-label extension, meaning that both patients and researchers were aware of who was receiving depemokimab and who had previously received placebo. This lack of blinding could introduce a degree of bias. Further research, including real-world studies, will be needed to confirm these findings and assess the long-term effects of depemokimab in broader patient populations. As Dr. Wechsler noted, continued monitoring and evaluation are crucial to ensure the ongoing safety and efficacy of this novel therapy.

For more information, Michael E. Wechsler, MD, can be reached at [email protected].

Individuals interested in learning more about asthma and available treatment options should consult with a qualified healthcare professional and refer to resources from organizations like the American Academy of Allergy, Asthma & Immunology and the American Lung Association.

The ongoing evaluation of depemokimab, as outlined in the NCT04718389 clinical trial, will continue to inform clinical practice and refine our understanding of its role in managing severe asthma.