OncoTargets and Therapy (Apr 2022)
An Innovative Site-Specific Anti-HER2 Antibody-Drug Conjugate with High Homogeneity and Improved Therapeutic Index
Abstract
Xiwu Hui,1,* Can Yuan,1,* Weirong Cao,1 Wenli Ge,1 Di Zhang,1 Mo Dan,2 Qian Zhao,2 Boning Liu,1,* Bing Yao1,* 1Institute of Quality Analysis, CSPC Megalith Biopharmaceutical Co., Ltd., Shijiazhuang, Hebei, People’s Republic of China; 2Pharmacology Center, CSPC Pharmaceutical Group Co., Ltd., Shijiazhuang, Hebei, People’s Republic of China*These authors contributed equally to this workCorrespondence: Boning Liu; Bing Yao, Institute of Quality Analysis, CSPC Megalith Biopharmaceutical Co., Ltd., No. 226 Huanghe Street, Shijiazhuang, Hebei, People’s Republic of China, Tel +8613284452520 ; +8613930148328, Fax +86031169085667, Email [email protected]; [email protected]: Antibody-drug conjugates (ADCs) have emerged as a potent cancer therapeutic option in recent years. DP303c is a HER2-targeting ADC with a cleavable linker-MMAE payload. The current study aimed to evaluate the therapeutic potentials of DP303c in vitro as well as in vivo.Materials and Methods: Size exclusion chromatography (SEC), reverse-phase high-performance liquid chromatography (RP-HPLC), and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to analyze the physicochemical characterization of DP303c. An enzyme-linked immunosorbent assay (ELISA), a cell-based assay, and bio-layer interferometry (BLI) were used to evaluate DP303c’s affinity with HER2 and Fc receptors. A confocal laser scanning microscopy was used to observe the internalization of DP303c. Antibody-dependent cell-mediated cytotoxicity (ADCC) and cytotoxicity assays were used to investigate the activity of DP303c in vitro. The antitumor activity of DP303c was assessed in vivo in the HER2-positive cell-derived xenograft model.Results: DP303c was a site-specific anti-HER2 antibody-drug conjugate with a monomethyl auristatin E (MMAE) with an average drug-to-antibody ratio (DAR) of 2.0. DP303c showed a high affinity with HER2 and could be effectively internalized. In vitro and in vivo, DP303c showed stronger antitumor activity as compared to trastuzumab-DM1 (T-DM1) in a series of HER2-positive cancer cells and cell-derived xenograft (CDX) models, especially in the lower HER2-expressing cells. DP303c also exhibited high serum stability and a good PK profile.Conclusion: DP303c was a steady and homogenous DAR 2 ADC that was predicted to deliver MMAE inhibitor to tumor cells. DP303c demonstrated remarkable anticancer efficacy against T-DM1 in xenograft models. DP303c was a strong candidate for the treatment of patients with HER2-positive cancer.Keywords: antibody-drug conjugates, ADCs, site-specific conjugation, engineered microbial transglutaminase, monomethyl auristatin E
