SIHUAN PHARM - VOLUNTARY ANNOUNCEMENT- COMPLETION OF ENROLLMENT OF ALL SUBJECTS IN PHASE III CLINICAL TRIAL IN CHINA OF ANAPRAZOLE SODIUM ENTERIC-COATED TABLETS (AN JIU WEI) FOR THE TREATMENT OF REFLUX ESOPHAGITIS

Sihuan Pharmaceutical Holdings Group Ltd.

四環醫藥控股集團有限公司

(incorporated in Bermuda with limited liability)

(Stock Code: 0460)

VOLUNTARY ANNOUNCEMENT

COMPLETION OF ENROLLMENT OF ALL SUBJECTS IN

PHASE III CLINICAL TRIAL IN CHINA OF ANAPRAZOLE

SODIUM ENTERIC-COATED TABLETS (AN JIU WEI) FOR THE

TREATMENT OF REFLUX ESOPHAGITIS

The board of directors (the "Board") of Sihuan Pharmaceutical Holdings Group Ltd. (the "Company" or "Sihuan Pharmaceutical", together with its subsidiaries, the "Group") is pleased to announce that the phase III clinical trial in China of the innovative drug Anaprazole Sodium Enteric-coated Tablets (trade name: An Jiu Wei) independently developed by Xuanzhu Biopharmaceutical Co., Ltd. ("Xuanzhu Biopharm") (Stock Code: 02575.HK), a non wholly-owned subsidiary of the Group, for the treatment of adult reflux esophagitis ("RE") has successfully completed the enrollment of all 500 subjects recently.

This phase III clinical trial is a multi-centre, randomized, double-blind, double-dummy, active-drug parallel-controlled pivotal study designed to evaluate the efficacy and safety of Anaprazole Sodium Enteric-coated Tablets in the treatment of Chinese adult subjects with RE. The primary clinical endpoint of the trial is the endoscopic healing rate of RE in subjects after a predetermined treatment cycle compared with the active control drug (within 8 weeks of treatment (including 8 weeks)); the secondary endpoints cover multiple efficacy indicators including the endoscopic healing rate of RE in subjects (at week 4 of treatment), changes from baseline in severity and frequency of major symptoms (heartburn and regurgitation) (at week 4 and week 8 of treatment). The safety indicators mainly include the types, incidence rates, and severity of adverse events.

ABOUT ANAPRAZOLE SODIUM ENTERIC-COATED TABLETS

Anaprazole Sodium Enteric-coated Tablets (trade name: An Jiu Wei) was approved for marketing by the National Medical Products Administration of China in June 2023 for the treatment of patients with duodenal ulcer. Anaprazole Sodium features an innovative structural design with characteristics including non-enzymatic plus multi-enzymatic metabolism and balanced intestinal-renal dual-channel excretion, with only 3.5% metabolized through CYP2C19, making it unaffected by CYP2C19 gene polymorphism. Compared with previous generations of proton pump inhibitors, Anaprazole Sodium has lower risk of drug-drug interactions, making it a safer choice for patients on multiple medications and those with renal impairment, and is a proton pump inhibitor more suitable for the Chinese population. As a Class 1 innovative drug in China, Anaprazole Sodium fills the gap in domestically developed proton pump inhibitors, bringing treatment options with both superior efficacy and safety to Chinese patients. In addition to the approved indication for duodenal ulcer, the phase III clinical study in China of Anaprazole Sodium Enteric-coated Tablets for the treatment of RE was fully launched in July 2025, and has recently successfully completed the enrollment of all 500 subjects.

ABOUT XUANZHU BIOPHARM

Xuanzhu Biopharm (Stock Code: 02575.HK) is an innovative pharmaceutical company rooted in China with a global perspective, focusing on major diseases such as digestion, oncology and non-alcoholic steatohepatitis, and is committed to the research and development ("R&D"), production and commercialization of class 1 drugs with core proprietary intellectual property rights. The company has a first-class R&D team that all core personnel have years of experience in new drug R&D. The company has two R&D platforms: small molecule chemistry and large molecule biopharmaceuticals. The dual engines drive the company's innovation and development, forming a product pipeline that covers small molecule chemistry, large molecule biopharmaceuticals, antibody-drug conjugate (ADC) and other types of products. With a focus on unmet major clinical needs, the company is committed to developing into a first class innovative pharmaceutical company with independent R&D, production, and sales capabilities.

ABOUT SIHUAN PHARMACEUTICAL

Founded in 2001 and listed on the Main Board of The Stock Exchange of Hong Kong Limited in 2010, Sihuan Pharmaceutical is an international medical aesthetic and pharmaceutical company led by innovation, with an independent and leading research and development technology platform, a rich global product pipeline, strong product registration capability, a full dosage form production platform with high efficiency and low cost and a mature and excellent sales system. Adhering to the overall strategic goal for the "full promotion of a two-wheel drive strategy of its medical aesthetics and biopharmaceutical businesses", Sihuan Pharmaceutical endeavors to build itself into a leading medical aesthetics and biopharmaceutical company in China.

This announcement is being made by the Company on a voluntary basis to update the 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, 22 March 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 nonexecutive directors of the Company are Mr. Tsang Wah Kwong, Dr. Zhu Xun and Mr. Wang Guan.