Abstract LB538: Characterization of GB263T, a tri-specific antibody against EGFR/cMET/cMET for NSCLC

Abstract

Abstract Background: The EGFR tyrosine kinase inhibitors (TKIs) have been effectively used for non-small cell lung cancer (NSCLC) driven by EGFR mutations. However, patients eventually develop drug resistance via various mechanisms such as secondary EGFR mutations and activation of alternative pathways. The cMET amplification is one of the resistant mechanisms. Amivantamab, a bispecific antibody to EGFR/c-Met has shown that concurrent inhibition of EGFR and c-Met can overcome resistance of EGFR-TKIs and improve patient outcomes. Thus, amivantamab has been approved for the treatment of advanced NSCLC patients with EGFR exon20ins mutations in the US. GB263T is a novel EGFR/cMET/cMET tri-specific antibody with enhanced ADCC function. The current study has demonstrated GB263T exhibited robust anti-tumor activity by in vitro and in vivo studies. Methods: GB263T has been extensively characterized. The binding/blocking activities were analyzed by SPR and ELISA. The protein levels and phosphorylation of EGFR/cMET were detected by Western Blot. Internalization ability was evaluated by confocal microscope. ADCC function was tested by Jurkat-CD16A-NFAT-Luc reporter system. Various CDX and PDX models were used to evaluate the in vivo efficacy in tumor inhibition. Results: GB263T showed high affinity binding to EGFR and cMET, with robust blocking activity. Moreover, GB263T induced receptor internalization and EGFR/cMET phosphorylation in NSCLC cell lines. GB263T dose-dependently inhibited the proliferation of cells containing EGFR exon 20 insertion mutations and C797S mutations. In addition, potent ADCC function against NSCLC cell lines was observed. Significant in vivo anti-tumor efficacy was demonstrated by multiple tumor models of EGFR exon 20 insertion, EGFR C797S mutation, cMET amplification, and cMET exon 14 skipping mutation. Conclusions: GB263T is a novel tri-specific antibody that exhibited robust anti-tumor activity. The preclinical data indicate that GB263T has great potential to become an effective therapeutics in the treatment of NSCLC. Citation Format: Qinglin Du, Wengang Zeng, Xueyan Yang, Liwen Liang, Xueqin Li, Yan Li, Yiqi Cao, Zongjun Xia, Jing Zhang, Qian Ding, Shuhua Han. Characterization of GB263T, a tri-specific antibody against EGFR/cMET/cMET for NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB538.