Suzhou, China; January 4, 2019 -- CStone Pharmaceuticals ("CStone") announced that a first patient was recently enrolled and dosed in the second Phase III clinical trial in China for CS1001, China's first fully human and full-length anti-PD-L1 monoclonal antibody. This multi-center clinical trial will be carried out in around forty hospitals including Shanghai Pulmonary Hospital, and will explore the safety and efficacy of CS1001 in combination with platinum-based chemotherapy as a first-line treatment for patients with advanced non-small cell lung cancer (NSCLC).

According to Chinese National Cancer Center data published in 2018, lung cancer is the most commonly diagnosed cancer in China at 781,000 cases annually, and have the highest mortality rate of all malignant tumors. NSCLC accounts for about 80% of all lung cancer, while about 75% of NSCLC patients are diagnosed at an advanced stage in China. The 5-year survival rate for advanced NSCLC is only 16.1%.

Dr. Frank Jiang, chairman and CEO of CStone, commented: "We are delighted that CS1001 has achieved the milestone of reaching the Phase III trial stage. Our hope is that CS1001 can be among the first combination therapies approved for first-line treatment for advanced NSCLC, and will benefit patients as soon as possible."

"Currently, for patients with advanced NSCLC with no driver mutation, first-line therapy is usually platinum-based two-drug chemotherapy, which has a poor survival rate," noted Dr. Jason Yang, CStone's Chief Medical Officer. "In this Phase III clinical trial we aim to assess the safety and efficacy of combination therapy using CS1001 and chemotherapy in both squamous and non-squamous advanced NSCLC. We expect to bring benefits to more possible range of patients."

About CS1001

CS1001 is an investigational monoclonal antibody directed against PD-L1 being developed by CStone Pharmaceuticals. Authorized by the U.S.-based Ligand Corporation, CS1001 is developed by the OMT transgenic animal platform, which can generate fully human antibodies in one step. As a fully human, full-length anti-PD-L1 monoclonal antibody, CS1001 mirrors natural G-type immune globulin 4 (IgG4) human antibody, which can reduce the risk of immunogenicity and potential toxicities in patients, a unique advantage over similar drugs.

Currently, CS1001 has completed a Phase I dose-escalation study in China, which showed the drug to be well-tolerated and produced sustained clinical benefit during the Phase Ia stage of development. In addition, two pivotal Phase II studies have been initiated in China: for natural killer cell/T-cell lymphoma (CS1001-201) and classical Hodgkin's lymphoma (CS1001-202). Meanwhile, Phase III studies are under way or being prepared both in China and globally for various serious tumor indications.

About CStone

CStone Pharmaceuticals is a biopharma company focused on developing and commercializing innovative immuno-oncology and molecularly targeted drugs to address significant unmet medical needs for cancer patients in China and worldwide. Since company inception three years ago, CStone has assembled a world-class management team that has a full spectrum of complementary skillsets from preclinical research to clinical development and commercialization. Through a dual source of innovation, comprised of internal research and external partnership, the company has built a rich oncology pipeline of 14 drug candidates with significant mono- and combination-therapy potential and synergies, including 4 assets exclusively in-licensed from Agios and Blueprint Medicine. Among CStone's portfolio, 4 late-stage drug candidates are at or near registrational trial. CStone's business model has a clear focus on clinical development, while at the same time, the company is rapidly developing its commercial and manufacturing capabilities. The company is backed by prestigious VC and PE funds with record-breaking amounts of equity investment, raising a combined total of USD 412 million in two financing rounds to date. 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 biopharma company by bringing innovative and differentiated oncology therapies to cancer patients in China and worldwide.

For more information about CStone Pharmaceuticals, please visit: www.cstonepharma.com.