(Suzhou, China, July 24th, 2020) —CStone Pharmaceuticals Co., Ltd. (“CStone” or the “Company”, HKEX: 2616) today announced that the US Food and Drug Administration (FDA) has granted an Orphan Drug Designation (ODD) to the Company’s drug candidate CS1003 (anti-PD-1 antibody) for the treatment of patients with hepatocellular carcinoma (HCC).

Provided for by the Orphan Drug Act (ODA), an Orphan Drug Designation is an incentive created by the FDA to promote the development of innovative drugs for the treatment of rare diseases and conditions. Orphan designation can qualify the sponsor of an orphan drug for 7 years of market exclusivity, along with a series of benefits provided by the FDA, including tax credits, reduction of or exemption from prescription drug user fees, R&D funding support, protocol assistance, and accelerated approval.

CS1003 is a humanized recombinant IgG4 monoclonal antibody targeting human programmed cell death protein 1 (PD-1), which is being developed by CStone for immunotherapy of various tumors. Compared to most of the monoclonal antibodies that bind human and monkey PD-1 that have been approved or are currently under clinical development, CS1003 can not only be cross-reactive to both human and murine PD-1, but also shows a unique competitive advantage in the efficacy test of homologous mouse tumor models. Currently, the Phase I clinical trials of CS1003 are being conducted in Australia, New Zealand and China. In addition, a global multi-center, phase III clinical study to evaluate the efficacy and safety of CS1003 in combination with lenvatinib as first-line treatment for patients with advanced HCC, has started patient enrollment.

Dr. Frank Jiang, Chairman and CEO of CStone Pharmaceuticals, said, “Hepatocellular carcinoma is a highly aggressive disease, and China has a large population living with HCC. The lack of effective treatments has led to overall poor prognosis for patients. CS1003 is one of the core drug candidates of CStone’s Immune-Oncology pipeline, and a number of clinical studies have been conducted to evaluate the combination therapy of CS1003 with other drugs. The orphan drug designation granted by the U.S. FDA will be a blessing for HCC patients who are in need of effective treatment.”

“CS1003 is an anti-PD-1 monoclonal antibody independently developed by CStone. Compared to other anti- PD-1 antibodies that have been launched or are currently under development, CS1003 has obvious differentiated advantages. The orphan drug status granted by the US FDA is an important development in CS1003's global strategic layout. We will continue to work on exploring the efficacy and safety of combination therapy in complex cancers such as hepatocellular carcinoma to address the unmet clinical needs of patients", added Sanhu Wang, Senior Vice President of Government and Regulatory Affairs of CStone Pharmaceuticals.

About CS 1003

PD-1 (Programmed cell death protein 1) is an inhibitory receptor that is preferentially expressed in T cells. Under normal physiological conditions, PD-1 will bind to programmed death ligand 1 or ligand 2 (PD-L1 / PD-L2), leading to reduced activity of T cells and the production of cytokines, which in turn protects the body from attacks by its own immune system. However, studies have found high level of PD-L1 expression on the surface of many solid tumor and some hematological malignant tumor cells in human. Tumor cells can successfully escape the identification and attack of the body's immune system through the binding of PD-L1 with PD-1 on T cells. Anti-cancer drugs such as PD-1 / PD-L1 immune checkpoint inhibitors can block this “tumor immune escape mechanism" and restore the anti-cancer function by the patients’ immune system.

CS1003 is a humanized recombinant IgG4 monoclonal antibody targeting human programmed cell death protein 1 (PD-1), which is being developed for immunotherapy of various tumors. Compared to most of the anti-PD-1 monoclonal antibodies that bind to human and monkey PD-1 (those that have either been approved or are being investigated in clinical trials), CS1003 can bind to both human and murine PD-1, and has shown unique competitive advantages in synergistic mouse models for drug efficacy testing.

About CStone

CStone Pharmaceuticals (HKEX:2616) is a biopharmaceutical company focused on developing and commercializing innovative immuno-oncology and precision medicines to address the unmet medical needs of cancer patients in China and worldwide. Established in 2015, CStone has assembled a world-class management team with extensive experience in innovative drug development, clinical research, and commercialization. The company has built an oncology-focused pipeline of 15 drug candidates with a strategic emphasis on immuno-oncology combination therapies. Currently, five late-stage candidates are at or near pivotal trials. With an experienced team, a rich pipeline, a robust clinical development-driven business model and substantial funding, CStone’s vision is to become globally recognized as a leading Chinese biopharmaceutical company by bringing innovative oncology therapies to cancer patients worldwide.

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