SIHUAN PHARM - VOLUNTARY ANNOUNCEMENT- SIHUAN PHARMACEUTICAL SIGNS STRATEGIC COLLABORATION AGREEMENT WITH BIOCYTOGEN TO ACCELERATE INNOVATIVE DRUG R&D IN WEIGHT LOSS AND OTHER AREAS THROUGH AI-DRIVEN FULLY HUMAN ANTIBODY DISCOVERY PLATFORM

investing public on the Group's latest business development, and does not constitute, and is not intended to be, an advertisement regarding the use of any medicine, surgical appliance, treatment or orally consumed product.

By order of the Board Sihuan Pharmaceutical Holdings Group Ltd. Dr. Che Fengsheng Chairman and Executive Director

Hong Kong, 1 April 2026

As at the date of this announcement, the executive directors of the Company are Dr. Che Fengsheng (Chairman), Dr. Guo Weicheng (Deputy Chairman and Chief Executive Officer),

Dr. Zhang Jionglong, Ms. Chen Yanling and Ms. Miao Guili; and the independent non- executive directors of the Company are Mr. Tsang Wah Kwong, Dr. Zhu Xun and Mr. Wang Guan.

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