IL-5/IL-5Rα biologics mepolizumab, reslizumab, benralizumab, depemokimab show broad efficacy across eosinophilia-associated diseases.
Background
Eosinophils are key inflammatory cells, and Interleukin-5 (IL-5) is their central regulator, controlling differentiation, maturation, survival, activation, and recruitment to inflamed tissues. This makes the IL-5/IL-5Rα pathway a critical therapeutic target for eosinophil-associated diseases. Current standard-of-care often involves systemic corticosteroids, which carry significant side effects with long-term use. Targeting IL-5 or its receptor offers a more specific approach to mitigate type 2 inflammation and reduce eosinophil-driven pathology, addressing a major unmet need in chronic inflammatory conditions.
Study Design
This comprehensive review synthesized clinical data on four biologics targeting the IL-5/IL-5Rα pathway: mepolizumab, reslizumab, benralizumab, and depemokimab. The authors evaluated their efficacy and safety across severe eosinophilic asthma (SEA), chronic rhinosinusitis with nasal polyps (CRSwNP), eosinophilic granulomatosis with polyangiitis (EGPA), and idiopathic hypereosinophilic syndrome (iHES). Data were drawn from a wide range of sources, including randomized controlled trials, extension studies, real-world cohorts, and meta-analyses, to provide a holistic view of their clinical utility.
Results
Targeting the IL-5/IL-5Rα pathway with biologics significantly reduces exacerbation risk and the need for long-term oral corticosteroids in severe eosinophilic asthma (SEA). Mepolizumab demonstrated broad efficacy, reducing asthma exacerbations, nasal polyp burden, EGPA relapse activity, and HES flares, alongside lowering peripheral blood eosinophils. It is approved for SEA, CRSwNP, EGPA, and HES. Reslizumab improved exacerbation rates and lung function in SEA, securing FDA and EMA approval for this indication. > Benralizumab produced rapid and near-complete blood and tissue eosinophil depletion, reducing exacerbation rates and oral corticosteroid use in SEA, and showed sustained remissions and corticosteroid-sparing efficacy in EGPA. Depemokimab, with its long-acting, twice-yearly dosing strategy, reduced exacerbation rates in SEA and improved nasal polyp burden in CRSwNP. Safety data from various study types were generally reassuring, indicating a favorable tolerability profile across these agents.
Key Findings
- Mepolizumab showed efficacy across SEA, CRSwNP, EGPA, and iHES, reducing exacerbations, polyp burden, and flares.
- Reslizumab improved exacerbation rates and lung function in SEA, with FDA/EMA approval for this use.
- Benralizumab achieved rapid, near-complete eosinophil depletion, reducing SEA exacerbations and showing EGPA remission.
- Depemokimab's twice-yearly dosing reduced SEA exacerbations and improved CRSwNP nasal polyp burden.
- Safety data for all four biologics were generally reassuring across various clinical settings.
Why It Matters
This review consolidates compelling evidence for the broad clinical utility of IL-5/IL-5Rα targeted biologics, offering a significant advance for patients with severe eosinophilic asthma and other eosinophilia-associated diseases. Clinicians now have multiple targeted options to reduce exacerbations, improve symptoms, and minimize reliance on systemic corticosteroids, which carry substantial long-term side effects. The introduction of depemokimab with its twice-yearly dosing regimen represents a practical breakthrough, potentially improving patient adherence and convenience for chronic management. These biologics are already approved, indicating they are readily available for clinical use, transforming treatment paradigms for these challenging conditions.
il-5
il-5ra
eosinophilia
severe-eosinophilic-asthma
chronic-rhinosinusitis-nasal-polyps
eosinophilic-granulomatosis-polyangiitis