Sichuan Kelun Pharmaceutical's (002422.SZ) subsidiary's new drug application for the core product Boduquyu single-chain antibody has been accepted.

Sichuan Kelun Pharmaceutical (002422.SZ) announced that the company recently learned that its controlling subsidiary, Sichuan Kelun Botai Biomedical Co., Ltd., has had the New Drug Application (NDA) for the antibody-drug conjugate (ADC) trastuzumab deruxtecan (formerly known as A166) targeting human epidermal growth factor receptor 2 (HER2) accepted by the China National Medical Products Administration (NMPA) Drug Evaluation Center (CDE). The drug is intended for the treatment of HER2-positive, unresectable or metastatic breast cancer in adults who have previously received at least one HER2-targeted therapy. The application is based on a multicenter, randomized, open-label, controlled Phase III clinical study, KL166-III-06, which evaluated the efficacy and safety of trastuzumab deruxtecan monotherapy compared to trastuzumab emtansine (T-DM1) in HER2-positive, unresectable, or metastatic breast cancer patients who have previously received trastuzumab and taxane therapy. In a pre-specified interim analysis, trastuzumab deruxtecan monotherapy showed a statistically significant and clinically meaningful improvement in progression-free survival (PFS) assessed by blinded independent central review (BICR) compared to T-DM1. Trastuzumab deruxtecan is an innovative HER2-targeted ADC developed by the company, which links a novel MMAF derivative (highly cytotoxic microtubule inhibitor Duo-5) to the HER2 monoclonal antibody through a stable enzymatic cleavable linker, with a drug-to-antibody ratio (DAR) of 2. Trastuzumab deruxtecan specifically binds to HER2 on the surface of tumor cells, gets internalized by the tumor cells, releases the toxin molecule Duo-5 intracellularly, induces tumor cell cycle arrest at the G2/M phase, and triggers tumor cell apoptosis. Trastuzumab deruxtecan can also inhibit HER2-mediated signaling pathways after binding to HER2 and has antibody-dependent cell-mediated cytotoxicity (ADCC) activity.