The U.S. Food and Drug Administration has granted approval to depemokimab, marketed as Exdensur, marking it as the inaugural ultra-long-acting biologic therapy administered just twice annually for individuals suffering from severe asthma exhibiting an eosinophilic profile. This milestone approval was shared by pharmaceutical giant GSK.
Expanded Treatment Option for Eosinophilic Severe Asthma
Administered via subcutaneous injection, this anti-interleukin-5 medication is now indicated as an additional maintenance therapy for managing severe asthma driven by type 2 inflammation. It is suitable for both adult patients and adolescents aged 12 years and above, providing a targeted approach to address this challenging condition.
GSK reports that approximately 80% of those with severe asthma display this eosinophilic characteristic. Clinically, severe asthma is identified by the necessity for medium- to high-dose inhaled corticosteroids combined with another controller agent, such as systemic corticosteroids or other biologics, to achieve stability. Even with these interventions, many patients experience persistent poor control.
Addressing Gaps in Current Biologic Therapies
Geoffrey Chupp, MD, a specialist in pulmonology and critical care at Yale University in New Haven, Connecticut, highlighted the limitations of existing options in a statement provided by GSK. He noted, “Existing biologic treatments for asthma tend to be underused, and the need for frequent injections proves inconvenient for numerous patients, often resulting in irregular adherence.”
Chupp further emphasized the potential benefits, stating, “This presents a significant chance to deliver extended protection against asthma exacerbations with fewer injections, which could enhance patient outcomes and optimize healthcare resource use.”
Historical Context and Low Adoption Rates
The very first biologic for asthma received FDA clearance back in 2003. Despite this, real-world data from Optum claims indicate that adoption among severe asthma patients remains below 20%. Emerging guideline revisions for moderate to severe asthma are anticipated to prioritize biologics, aiming to curtail reliance on oral corticosteroids-a shift supported by evidence demonstrating superior asthma management.
Insights from patient surveys reinforce the appeal of extended dosing schedules, suggesting that less frequent administrations could increase willingness to pursue biologics for asthma or related type 2 inflammatory disorders.
Robust Evidence from Pivotal Clinical Trials
The approval of depemokimab was underpinned by results from the SWIFT-1 and SWIFT-2 phase III trials, which enrolled a total of 792 participants aged 12 and older with severe asthma. In these studies, patients were allocated in a 2:1 fashion to receive either 100 mg of depemokimab subcutaneously or a placebo at baseline and week 26, alongside their standard-of-care regimen. This regimen typically incorporated medium- or high-dose inhaled glucocorticoids plus at least one additional controller medication.
To qualify, participants needed a history of at least two exacerbations in the preceding year that necessitated systemic corticosteroids, coupled with a blood eosinophil count of 300 cells/μL or higher within the past year, or 150 cells/μL at the time of screening.
Over the 52-week study period, depemokimab demonstrated substantial efficacy. In SWIFT-1, it lowered the annualized exacerbation rate by 58% (rate ratio 0.42, 95% CI 0.30-0.59), with rates of 0.46 for depemokimab compared to 1.11 for placebo. Similarly, SWIFT-2 showed a 48% reduction (rate ratio 0.52, 95% CI 0.36-0.73), with rates of 0.56 versus 1.08, respectively. Both trials achieved statistical significance (P < 0.001).
Key Safety Considerations and Usage Guidelines
The prescribing information explicitly states that depemokimab is not intended for treating acute bronchospasm or status asthmaticus episodes. Furthermore, clinicians should avoid sudden cessation of systemic or inhaled corticosteroids when initiating therapy; instead, a gradual taper is recommended if clinically suitable.
Discontinuation is advised in cases of hypersensitivity reactions, including severe anaphylaxis. For patients undergoing treatment for helminth infections that do not resolve, therapy should be paused. Ideally, any active helminth infections should be resolved prior to commencing depemokimab.
In the clinical trials, the most frequently reported adverse events, occurring in 4% or more of participants, included infections of the upper respiratory tract, allergic rhinitis, influenza, joint pain (arthralgia), and inflammation of the pharynx (pharyngitis).
Broadening Horizons: Ongoing Research Applications
Beyond asthma, depemokimab is under investigation for several other conditions involving type 2 inflammation. These include chronic rhinosinusitis with nasal polyps, uncontrolled moderate to severe chronic obstructive pulmonary disease characterized by type 2 inflammation, eosinophilic granulomatosis with polyangiitis, and hypereosinophilic syndrome. These efforts highlight the drug’s versatility in tackling a spectrum of eosinophil-driven diseases.
With its biannual dosing paradigm, depemokimab represents a promising advancement, potentially overcoming longstanding barriers to biologic adherence and improving quality of life for patients grappling with severe eosinophilic asthma.
