Suzhou, China; December 29, 2017 -- CStone Pharmaceuticals (Suzhou) Co., Ltd, today announced that an investigational new drug (IND) filing has been submitted to Human Research Ethics Committees of the Ashford Cancer Center in Australia for CS1002, an independently-developed investigational cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) inhibitor. The application represents CStone's third molecule to be submitted for clinical trial approval overseas during 2017.

CS1002 is an immunoglobulin G (IgG) 1 class, fully human monoclonal antibody (mAb) that has demonstrated high levels of specificity and selectivity for CTLA-4 during pre-clinical studies and is expected to provide a new therapeutic option for cancer patients. The molecule will primarily be developed alongside other candidate drugs as part of combination therapies.

Dr. Frank Jiang, Chief Executive Officer (CEO) of CStone commented: "We are very pleased to take another major step forward in terms of our global R&D strategy, and CS1002 represents a new milestone for CStone in the field of cancer immunotherapy.  During December 2017, we have now successfully made three IND filings for drug candidates to enter international clinical trials. This will enrich our clinical research strategy for combination immunotherapies, and help to accelerate these drug candidates towards early registrations as new treatment options addressing the unmet medical needs of a broad patient population."

Since CStone was established, a number of achievements have been made in the field of cancer immunotherapy. The company has independently developed China's first full-length, fully human anti-PD-L1 monoclonal antibody candidate, CS1001, currently at Phase I clinical trial stage in China in patients with advanced cancers. IND filings have also been recently filed in Australia for the MEK inhibitor CS3006 and the anti-PD-1 antibody CS1003. In the future, CStone aims to leverage its unique advantages in clinical development to achieve accelerated market approvals for a range of new therapies that benefit cancer patients around the world.

About the CTLA-4 pathway

Cytotoxic T lymphocyte associated antigen 4 (CTLA-4), also known as CD152, is a transmembrane protein encoded by the CTLA-4 gene that can down-regulate the activity of T cells when binding with its ligand, B7, a pathway also used by tumor cells to avoid T lymphocyte attack. Consequently, blockade of the CTLA-4 pathway can stimulate T cell activation and proliferation to induce or enhance anti-tumor immune responses. CTLA-4 provides a new immuno-therapeutic approach to a number of diseases, including tumors.

Presently, Bristol-Myers Squibb's Yervoy (ipilimumab) is the only anti-CTLA-4 antibody to gain a market approval worldwide, although Yervoy has not yet been approved in China. Pre-clinical tests have shown that CS1002 has a relatively strong affinity to CTLA-4 and is expected to match Yervoy in terms of efficacy.

About CStone Pharmaceuticals

CStone Pharmaceuticals is a biopharmaceutical company devoted to the development of a new generation of innovative drugs. With its broad immuno-oncology pipeline, CStone is pursuing a development strategy focusing on combination therapy. In July of 2016, CStone Pharmaceuticals announced the completion of its $150 million Series A financing, led by three prestigious VC/PE funds: Oriza Seed Venture Capital, Boyu Capital and WuXi Healthcare Ventures. All members of the management team are seasoned executives from top multinational pharmaceutical companies. CStone has successfully built up an industry leading team with clinical development and translational medicine as its core competence. This enables CStone to accelerate drug approval timeline, while at the same time, apply global standard practices to ensure clinical trial quality. The unique advantages in clinical development, funding and pipeline also positions CStone as the partner of choice for multinational pharmaceutical / biotech companies to develop drugs in China and the Asia Pacific region.

For more information, please contact:

CStone Pharmaceuticals Co., Ltd.

Corporate Development Department

TEL: +86-(0)21-6109-7678

FAX: +86-(0)21-6109-7689