The board of directors of Simcere Pharmaceutical Group Limited announced that, on January 10, 2024, SIM0501 tablets, a small-molecule inhibitor of Ubiquitin Specific Peptidase 1 ("USP1"), which is an anti-tumor drug candidate independently developed by the Group, has obtained the Clinical Trial Approval issued by the National Medical Products Administration ("Guo Jia Yao Pin Jian Du Guan Li Ju") of China, pursuant to which, SIM0501 tablets have been approved to initiate clinical trials for advanced malignant solid tumors as monotherapy. SIM0501 is an oral, non-covalent and highly selective inhibitor of USP1. USP1 is found to be overexpressed in various tumors and plays a key role in DNA damage response and repair.

The inhibition of USP1 can promote apoptosis in tumors, especially in the tumors with homologous recombination deficiency ("HRD"). Following the success of PARP inhibitor (PARPi), the USP1 inhibitor is expected to provide innovative solutions for more patients with solid tumors in the field of "synthetic lethality". In preclinical in vitro and in vivo pharmacology studies, SIM0501 has shown significant anti-proliferation activity against HRD tumors as a monotherapy or in combination with PARPi, which demonstrates high potential for clinical development.

On December 2, 2023, the Investigational New Drug (IND) application of SIM0501 to initiate clinical trials for advanced solid tumors was approved by the U.S. Food and Drug Administration (FDA).