Higher Binding Affinity and
in vitro Potency of Reslizumab for Interleukin-5 Compared With Mepolizumab.
ALLERGY, ASTHMA & IMMUNOLOGY RESEARCH 2019;
11:291-298. [PMID:
30661320 PMCID:
PMC6340799 DOI:
10.4168/aair.2019.11.2.291]
[Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/28/2018] [Accepted: 09/04/2018] [Indexed: 11/21/2022]
Abstract
Reslizumab and mepolizumab are recently approved monoclonal antibodies for the treatment of severe (uncontrolled) eosinophilic asthma. Both are effective in neutralizing the function of interleukin-5 (IL-5). This study is the first to compare the binding affinity and in vitro potency of both antibodies in head-to-head assays. Two assays assessed binding affinity (using the equilibrium dissociation constant [KD]) of each drug for human IL-5. In the Biacore surface plasmon resonance assay, the association constant (kon) values for human IL-5 for reslizumab and mepolizumab were 3.93 × 106 and 1.83 × 105, respectively. The dissociation constant (koff) values were 4.29 × 10−4 and 2.14 × 10−4, respectively. Calculated KD values for human IL-5 for reslizumab and mepolizumab were 109 and 1,170 pM, respectively, representing an approximately 11-fold stronger binding affinity with reslizumab. In the Kinetic Exclusion Assay, the kon values for human IL-5 for reslizumab and mepolizumab were 3.17 × 106 and 1.32 × 105, respectively. The koff values were 1.36 × 10−5 and 1.48 × 10−5, respectively. Measured KD values for human IL-5 for reslizumab and mepolizumab were 4.3 and 112 pM, respectively, representing an approximately 26-fold stronger binding affinity for reslizumab. A human-IL-5-dependent cell proliferation assay was developed to assess in vitro potency, based on a human cell line selected for enhanced surface expression of IL-5 receptor-alpha and consistent proliferation response to IL-5. The concentration at which 50% inhibition occurred (IC50) was determined for both antibodies. Reslizumab and mepolizumab inhibited IL-5-dependent cell proliferation, with IC50 values of approximately 91.1 and 286.5 pM, respectively, representing on average 3.1-fold higher potency with reslizumab. In conclusion, comparative assays show that reslizumab has higher affinity binding for and in vitro potency against human IL-5 compared with mepolizumab. However, these results do not take into consideration the different methods of administration of reslizumab and mepolizumab.
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