Last reviewed 2026-04-23 · How we verify

Liquid mepolizumab

Mepolizumab is a monoclonal antibody that binds to interleukin-5 (IL-5) and prevents its interaction with eosinophils, reducing eosinophil production and activation.

Mepolizumab is a monoclonal antibody that binds to interleukin-5 (IL-5) and prevents its interaction with eosinophils, reducing eosinophil production and activation. Used for Severe eosinophilic asthma, Eosinophilic granulomatosis with polyangiitis (EGPA), Chronic rhinosinusitis with nasal polyps (CRSNP).

At a glance

Mechanism of action

Mepolizumab targets IL-5, a key cytokine involved in eosinophil development, recruitment, and survival. By neutralizing IL-5, the drug reduces circulating and tissue eosinophil levels, thereby decreasing eosinophil-mediated inflammation. This mechanism is particularly effective in conditions characterized by eosinophilic inflammation, such as severe eosinophilic asthma and eosinophilic granulomatosis with polyangiitis (EGPA).

Approved indications

• Severe eosinophilic asthma
• Eosinophilic granulomatosis with polyangiitis (EGPA)
• Chronic rhinosinusitis with nasal polyps (CRSNP)

Common side effects

• Headache
• Injection site reactions
• Upper respiratory tract infections
• Pyrexia

Key clinical trials

• A Study of GSK3511294 (Depemokimab) Compared With Mepolizumab or Benralizumab in Participants With Severe Asthma With an Eosinophilic Phenotype (PHASE3)
• Mepolizumab as Add-on Treatment IN Participants With COPD Characterized by Frequent Exacerbations and Eosinophil Level (PHASE3)
• Study of Mepolizumab Autoinjector in Asthmatics (PHASE3)
• A Study to Compare the Pharmacokinetics of Mepolizumab as a Liquid Drug in a Safety Syringe or an Autoinjector Versus Lyophilised Drug (PHASE3)
• Study of Mepolizumab Safety Syringe in Asthmatics (PHASE3)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.