Suzhou, China, September 7, 2026—CStone Pharmaceuticals (“CStone,” HKEX: 2616), an innovation-driven biopharmaceutical company focused on the research and development of therapies for oncology, immunology, inflammation, and other key disease areas, today announced that the shares of the Company have been included in the eligible securities list for southbound trading under Stock Connect, effective September 7, 2026.

Dr. Jason Yang, CEO, President of R&D, and Executive Director at CStone, commented, “Inclusion in the Southbound Stock Connect reflects strong recognition by the capital markets of our innovation capabilities and long-term growth potential. We expect this inclusion to further broaden our investor base and enhance the liquidity of our shares in the secondary market. Looking ahead, we will continue to advance the global development of our core assets, strengthen our competitive position through efficient pipeline execution and commercialization, and deliver sustainable, long-term value for our shareholders.”

CStone remains committed to addressing unmet clinical needs worldwide through a differentiated innovation strategy. Our core asset, CS2009, a PD-1/VEGF/CTLA-4 trispecific antibody, continues to progress efficiently through global Phase I/II clinical development, with the first wave of global Phase III registrational trials expected to be initiated by the end of 2026. Our proprietary EGFR/HER3 bispecific ADC, CS5007, has also entered global Phase I clinical development, with the study being conducted concurrently in China and Australia. In addition, multiple next-generation ADC programs, along with bispecific antibody programs in immunology and inflammation, are advancing toward Investigational New Drug (IND) submissions.

About CStone

CStone (HKEX: 2616), established in late 2015, is an innovation-driven biopharmaceutical company focused on the research and development of therapies for oncology, immunology, inflammation, and other key disease areas. Dedicated to addressing patients' unmet medical needs in China and globally, the Company has made significant strides since its inception. To date, the Company has successfully launched four innovative drugs and secured approvals for 21 new drug applications covering nine indications. The Company's pipeline comprises 13 promising innovative candidates, including antibody-drug conjugates (ADCs), mono- and multispecific antibodies, immunotherapies and precision medicines. CStone has an experienced management team with comprehensive capabilities spanning the entire drug development spectrum, from preclinical and translational research to clinical development, drug manufacturing, business development, and commercialization.

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

IR contact: ir@cstonepharma.com

PR contact: pr@cstonepharma.com

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