The management of Type 2 inflammatory diseases—most notably severe asthma and chronic rhinosinusitis—has been completely revolutionized by the advent of targeted biologics. However, a persistent hurdle in clinical practice has been the treatment burden and patient adherence associated with frequent dosing schedules.

Enter Depemokimab (development code: GSK3511294, recently approved under the brand name Exdensur). As the world's first ultra-long-acting respiratory biologic, Depemokimab offers researchers and clinicians a highly potent mechanism to achieve sustained suppression of inflammation with an unprecedented twice-yearly dosing interval.

Here is everything researchers need to know about the structural profile, mechanism of action (MoA), manufacturer details, and the latest clinical data for Depemokimab.

Depemokimab is engineered to precisely neutralize a specific cytokine pathway responsible for eosinophil-driven inflammation, but its true differentiator lies in its pharmacokinetic profile.

• The Molecule: Depemokimab is a humanized monoclonal antibody. It has been specifically engineered with distinct structural modifications to its Fc region to significantly extend its half-life, alongside enhanced binding affinity and potency.

• The Target: It selectively targets and neutralizes Interleukin-5 (IL-5), the core cytokine in Type 2 inflammation.

• Developer: The drug was discovered and developed by GSK (GlaxoSmithKline), expanding on their extensive legacy in respiratory medicine and IL-5 inhibition.

• Administration: It is formulated for subcutaneous injection. Because of its ultra-long-acting design, the maintenance dosing schedule is just once every six months (twice yearly).

To understand Depemokimab's profound efficacy, researchers must look at the biology of eosinophils, the primary effector cells in Type 2 inflammation:

1. The Role of IL-5: In diseases like severe eosinophilic asthma and chronic rhinosinusitis with nasal polyps (CRSwNP), patients exhibit an overactive Type 2 immune response. IL-5 is the central cytokine responsible for the growth, differentiation, recruitment, activation, and survival of eosinophils in the bone marrow and mucosal tissues.

2. Cytokine Neutralization: Depemokimab binds directly to circulating IL-5 with exceptionally high affinity.

3. Receptor Blockade: By binding to the cytokine, Depemokimab sterically hinders IL-5 from interacting with the alpha chain of the IL-5 receptor (IL-5R$\alpha$) expressed on the surface of eosinophils.

4. Eosinophil Depletion: Without the vital survival signals provided by IL-5, the eosinophil population rapidly undergoes apoptosis. This profound depletion of eosinophils from the blood and airway tissues directly shuts down the downstream inflammatory cascade, preventing asthma exacerbations, mucus hypersecretion, and the formation of nasal polyps.

Depemokimab's regulatory approvals were driven by robust data from two massive, parallel Phase 3 clinical trial programs evaluating its efficacy over 52 weeks: the SWIFT trials for severe asthma and the ANCHOR trials for CRSwNP.

Severe Eosinophilic Asthma (SWIFT-1 & SWIFT-2)

In these replicate, double-blind, placebo-controlled trials, patients receiving Depemokimab on top of standard-of-care inhalers saw massive reductions in asthma attacks:

Chronic Rhinosinusitis with Nasal Polyps (ANCHOR-1 & ANCHOR-2)

Similarly, in patients with CRSwNP, twice-yearly Depemokimab demonstrated statistically significant and clinically meaningful improvements in both endoscopic nasal polyp size (NPS) and patient-reported nasal obstruction severity compared to placebo.

Across all major trials, Depemokimab was generally well-tolerated. The safety profile and incidence of adverse events (such as upper respiratory tract infections and COVID-19) were highly comparable between the Depemokimab and placebo groups.

Depemokimab is rapidly clearing major regulatory milestones globally. It received US FDA approval in December 2025 for the add-on maintenance treatment of severe asthma with an eosinophilic phenotype in patients aged 12 and older. This was quickly followed by European Commission (EU) approval in February 2026 for both severe asthma and CRSwNP.

GSK is not stopping with asthma and nasal polyps. Depemokimab’s unique pharmacokinetic profile makes it an attractive candidate for a wide array of other IL-5-mediated diseases. It is currently being investigated in late-stage Phase 3 clinical trials for Eosinophilic Granulomatosis with Polyangiitis (EGPA), Hypereosinophilic Syndrome (HES), and Chronic Obstructive Pulmonary Disease (COPD).

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