Effect of the ADCC-Modulating Mutations and the Selection of Human IgG Isotypes on Physicochemical Properties of Fc

Monoclonal antibodies, particularly IgGs and Ig-based molecules, are a well-established and growing class of biotherapeutic drugs. In order to improve efficacy, potency and pharmacokinetics of these therapeutic drugs, pharmaceutical industries have investigated significantly in engineering fragment crystallizable (Fc) domain of these drugs to optimize the interactions of these drugs and Fc gamma receptors (FcgRs) in recent ten years. The biological function of the therapeutics with the antibody-dependent cellular cytotoxicity (ADCC) enhanced double mutation (S239D/I332E) of isotype IgG1, the ADCC reduced double mutation (L234A/ L235A) of isotype IgG1, and ADCC reduced isotype IgG4 has been well understood. However, limited information regarding the effect of these mutations or isotype difference on physicochemical properties (PCP), developability, and manufacturability of therapeutics bearing these different Fc regions is available. In this report, we systematically characterize the effects of the mutations and IgG4 isotype on conformation stability, colloidal stability, solubility, and storage stability at accelerated conditions in two buffer systems using six Fc variants. Our results provide a basis for selecting appropriate Fc region during development of IgG or Ig-based therapeutics and predicting effect of the mutations on CMC development process. (c) 2022 American Pharmacists Association. Published by Elsevier Inc. All rights reserved.

Automated summary

Monoclonal antibodies, especially IgGs and Ig-based molecules, are widely used biotherapeutic drugs. The engineering of the Fc domain of these drugs to optimize their interactions with Fc gamma receptors (FcgRs) has been extensively studied in recent years. However, limited information is available regarding the effects of mutations and isotype differences on the physicochemical properties and manufacturability of these drugs. This study systematically characterizes the effects of mutations and IgG4 isotype on the stability and manufacturability of six Fc variants, providing a basis for selecting appropriate Fc regions and predicting the impact of mutations on the drug development process.