Structural basis of a novel heterodimeric Fc for bispecific antibody production

Abstract

Bispecific antibodies provide an efficient tool for combinational clinical therapy. Here we have engineered a heterodimeric Fc for bispecific antibodies production by combining the knob-into-hole and electrostatic steering strategies where a bulky hydrophobic residue Phe405 of the IgG CH3 interface is mutated to a charged residue Lys and Lys409 of the corresponding CH3 domain is mutated to Ala. The crystal structure of this Fc heterodimer solved here at 2.7Å resolution revealed how these two mutations resulted a complementary binding interface and explained why F405K mutation could effectively inhibit Fc homodimer formation during protein expression. An anti-HER2 bispecific antibody derived from trastuzumab and pertuzumab was generated by this heterodimeric Fc. It showed comparable or improved efficacy than the combination of trastuzumab and pertuzumab in inhibiting proliferation of cancer cells in vitro and in vivo. Overall this study shows that the heterodimeric Fc engineered here provides an efficient platform for generating active bispecific antibody for cancer treatment.

Toward Drug-Like Multispecific Antibodies by Design

“…However, identifying a promiscuous light chain that enables binding of two different antigens can be a significant undertaking. Still others have engineered the heavy chain-light chain interface to promote selective association of the correct heavy chain-light chain pairs, or perhaps just as importantly, disfavor incorrect chain pairing [ 70 , 71 , 72 , 73 ]. This type of engineering has the potential to allow direct expression and production of heterodimeric antibodies, which are antibodies composed of half of two different antibodies dimerized into a full IgG through heterotypic Fc pairing [ 74 , 75 ].…”

Anti-ErbB2 immunotherapeutics: struggling to make better antibodies for cancer therapy

“…Currently, two bispecific/biparatopic antibodies, incorporating the paratopes of trastuzumab and pertuzumab, are in Phase 2 clinical studies and two in Phase 1 clinical studies. KN026 was obtained by heterodimeric Fc engineering, 51 and showed encouraging clinical results particularly in patients with advanced gastric/gastroesophageal junction cancer. ZW25 biparatopic antibody, also generated by using a proprietary technology, showed excellent tolerability and considerable efficacy in breast and gastroesophageal cancer patients that had progressed after therapies that included trastuzumab, pertuzumab, and T-DM1.…”

A cytokine receptor-masked IL2 prodrug selectively activates tumor-infiltrating lymphocytes for potent antitumor therapy

“…As a result, we engineered designs of ProIL2 to minimize potential steric clash that would prevent MMP access of the cleavable linker. These engineering strategies involved synthesizing hIgG1 heterodimers 15 , incorporating different or truncated IL-2 receptor subunits, and altering the orientation of domains on both the N and C termini of each Fc arm. We initially rejected the designs that exhibited minimal IL-2 blocking activity and recombinant MMP cleavage.…”