Mepolizumab is a humanized IL-5 antagonist monoclonal antibody produced by recombinant DNA technology in Chinese hamster ovary cells. It has a molecular weight of approximately 149 kDa. It was approved by the FDA in November, 2015 for the treatment of asthma under the brand name Nucala (marketed by GlaxoSmithKline). Mepolizumab has been investigated in the treatment of severe nasal polyposis, among numerous other conditions.
|Protein chemical formula||Not Available|
|Protein average weight||149000.0 Da|
|External IDs||240563 / SB-240563|
|Product Ingredients||Not Available|
|Approved Prescription Products|
|Approved Generic Prescription Products||Not Available|
|Approved Over the Counter Products||Not Available|
|Unapproved/Other Products||Not Available|
|Brand mixtures||Not Available|
Mepolizumab is indicated for add-on maintenance treatment of severe eosinophilic asthma, as identified by blood eosinophils greater than or equal to 150 cells/μl at initiation of treatment or blood eosinophils greater than or equal to 300 cells/μl in the past 12 months, in patients aged 12 years and older. Mepolizumab has been shown to reduce exacerbations of asthma in patients with an exacerbation history
The pharmacodynamic response (blood eosinophil reduction) following repeat doses of mepolizumab administered subcutaneously or intravenously was evaluated in subjects with asthma and blood eosinophil levels greater than 200 cells/mcL. Subjects received 1 of 4 mepolizumab treatments (administered every 28 days for a total of 3 doses): 12.5 mg SC, 125 mg SC, 250 mg SC, or 75 mg IV. Sixty-six (66) of the 70 randomized subjects completed the trial. Compared with baseline levels, blood eosinophils decreased in a dose-dependent manner. A reduction in blood eosinophil levels was observed in all treatment groups by Day 3. On Day 84 (4 weeks post-last dose), the observed geometric mean reduction from baseline in blood eosinophils was 64%, 78%, 84%, and 90% in the 12.5-mg SC, 75-mg IV, 125-mg SC, and 250-mg SC treatment groups, respectively. The model-predicted SC doses providing 50% and 90% of maximal reduction of blood eosinophils at Day 84 were estimated to be 11 and 99 mg, respectively. These results, along with the clinical efficacy data from the dose-ranging exacerbation trial (Trial 1) supported the evaluation of mepolizumab 75 mg IV and 100 mg SC in the confirmatory trials [see Clinical Studies (14)]. Following SC administration of mepolizumab 100 mg every 4 weeks for 32 weeks (Trial 2), blood eosinophils were reduced to a geometric mean count of 40 cells/mcL, which corresponds to a geometric mean reduction of 84% compared with placebo. This magnitude of reduction was observed within 4 weeks of treatment and was maintained throughout the treatment period.
|Mechanism of action|
Mepolizumab is an interleukin-5 antagonist (IgG1 kappa). IL-5 is the major cytokine responsible for the growth and differentiation, recruitment, activation, and survival of eosinophils. Mepolizumab binds to IL-5 with a dissociation constant of 100 pM, inhibiting the bioactivity of IL-5 by blocking its binding to the alpha chain of the IL-5 receptor complex expressed on the eosinophil cell surface. Inflammation is an important component in the pathogenesis of asthma. Multiple cell types (e.g., mast cells, eosinophils, neutrophils, macrophages, lymphocytes) and mediators (e.g., histamine, eicosanoids, leukotrienes, cytokines) are involved in inflammation. Mepolizumab, by inhibiting IL-5 signaling, reduces the production and survival of eosinophils; however, the mechanism of mepolizumab action in asthma has not been definitively established.
Following 100-mg SC administration in the upper arm of subjects with asthma, the bioavailability of mepolizumab was estimated to be approximately 80%. Following repeat SC administration once every 4 weeks, there was approximately a 2-fold accumulation at steady state.
|Volume of distribution|
The population central volume of distribution of mepolizumab in patients with asthma is estimated to be 3.6 L for a 70-kg individual.
Mepolizumab binds to IL-5 with a dissociation constant of 100 pM.
Mepolizumab is a humanized IgG1 monoclonal antibody that is degraded by proteolytic enzymes widely distributed in the body and not restricted to hepatic tissue.
|Route of elimination||Not Available|
The mean terminal half-life (t1/2) ranged from 16 to 22 days.
The population apparent systemic clearance of mepolizumab in patients with asthma is estimated to be 0.28 L/day for a 70-kg individual.
|Pharmacogenomic Effects/ADRs||Not Available|
|Food Interactions||Not Available|
|Synthesis Reference||Not Available|
|AHFS Codes||Not Available|
|PDB Entries||Not Available|
|FDA label||Download (3.56 MB)|
|MSDS||Download (86.4 KB)|
|Experimental Properties||Not Available|
|Super Class||Organic Acids|
|Class||Carboxylic Acids and Derivatives|
|Sub Class||Amino Acids, Peptides, and Analogues|
|Alternative Parents||Not Available|
|Molecular Framework||Not Available|
|External Descriptors||Not Available|
- Pharmacological action
- General Function:
- Interleukin-5 receptor binding
- Specific Function:
- Factor that induces terminal differentiation of late-developing B-cells to immunoglobulin secreting cells.
- Gene Name:
- Uniprot ID:
- Molecular Weight:
- 15237.695 Da
- Basavaraju KP, Wong T: Eosinophilic oesophagitis: a common cause of dysphagia in young adults? Int J Clin Pract. 2008 Jul;62(7):1096-107. doi: 10.1111/j.1742-1241.2008.01782.x. [PubMed:18564273 ]
- Garrett JK, Jameson SC, Thomson B, Collins MH, Wagoner LE, Freese DK, Beck LA, Boyce JA, Filipovich AH, Villanueva JM, Sutton SA, Assa'ad AH, Rothenberg ME: Anti-interleukin-5 (mepolizumab) therapy for hypereosinophilic syndromes. J Allergy Clin Immunol. 2004 Jan;113(1):115-9. Epub 2003 Dec 12. [PubMed:14699394 ]