SUZHOU, China, October 13, 2021, Transcenta Holding Limited ("Transcenta") (HKEX: 06628), a clinical stage biopharmaceutical company with fully-integrated capabilities in discovery, research, development and manufacturing of antibody-based therapeutics, announces that the Center for Drug Evaluation (CDE) of the China National Medical Products Administration (NMPA) has accepted IND application of its PD-L1/TGF-β bi-functional antibody TST005. Transcenta has received IND clearance for TST005 from US FDA on April 17, 2021 and the first US patient has been dosed in the global Phase I clinical trial on July 15, 2021.

TST005 is the second bi-functional anti-PD-L1 and TGF-β trap fusion protein entering the global clinical stage. It simultaneously targets two immuno-suppressive pathways, transforming growth factor -β (TGF-β) and programmed cell death ligand-1 (PD-L1), that are commonly used by cancer cells to evade the immune system. TST005 consists of a high affinity PD-L1 antibody fused with an engineered TGF-β Receptor Type II protein in its C-terminal. TST005 lacks FcR binding activity and thus has reduced FcR mediated killing of PD-L1 expressing effector T cells. TST005's high PD-L1 binding activity and enhanced TGF-β trap stability enables the targeted delivery of TGF-β trap into PD-L1 expressing tumors, thereby minimizing off-target toxicities of systemic inhibition of TGF-β signaling. TST005 displayed potent activity in vitro in reversing TGF-β induced T-cell suppression. In multiple syngeneic tumor models, TST005 induced significant increase of CD8 T-cell infiltration into PD-L1 expressing tumors and displayed dose-dependent tumor growth inhibition in tumor model not sensitive to PD-(L)1 treatment due to high level TGF-β. TST005 is well tolerated in non-human primates and displayed a linear PK profile. TST005 is a potential differentiated bi-functional immunotherapy candidate with improved therapeutic window.

“TST005 is one of the few leading PD-L1/TGF-β bi-functional antibody-targeting drug candidates currently under clinical development globally.” said Dr. Michael Shi, EVP, Head of Global R&D and CMO of Transcenta, “PD-L1/TGF-β bi-functional antibodies can effectively prevent tumor cells from escaping immune regulation, therefore, TST005 has the potential to offer a promising new therapeutic strategy for combating cancer immune evasion.”

A global Phase I trial for TST005 with both US and China using the same protocol is currently ongoing. Please refer to http://www.clinicaltrials.gov for additional information about this clinical trial (NCT04958434).