HANSOH PHARMA - VOLUNTARY ANNOUNCEMENT - THE PHASE III CLINICAL STUDY OF HS-20093 IN THE TREATMENT OF

SMALL CELL LUNG CANCER HAS MET THE PRIMARY ENDPOINT

Hansoh Pharmaceutical Group Company Limited

翰森製藥集團有限公司

(Incorporated in the Cayman Islands with limited liability)

(Stock Code: 3692)

VOLUNTARY ANNOUNCEMENT

THE PHASE III CLINICAL STUDY OF HS-20093 IN THE TREATMENT OF

SMALL CELL LUNG CANCER HAS MET THE PRIMARY ENDPOINT

The board of directors (the "Board") of Hansoh Pharmaceutical Group Company Limited (the "Company" and together with its subsidiaries, the "Group") is pleased to announce that, HS-20093, the Group's self-developed B7-H3 directed antibody-drug conjugate (ADC), met the primary endpoint of overall survival ("OS") in a pivotal Phase III clinical trial (ARTEMIS-008) for patients with advanced or relapsed small cell lung cancer (SCLC) after prior platinum-based therapy. At a pre-specified interim analysis, HS-20093 demonstrated statistically significant and clinically meaningful OS improvements compared with topotecan. Consistent benefit was also observed across secondary clinical endpoints, including progression-free survival (PFS). The safety profile was consistent with prior findings, and no new safety signals were identified.

Based on these positive results, the Group will initiate communications with regulatory authority to advance preparations for a biologics license application in China in the near term. The detailed data from the ARTEMIS-008 study is expected to be presented at an upcoming international oncology conference.

By Order of the Board

Hansoh Pharmaceutical Group Company Limited Zhong Huijuan

Chairlady

Hong Kong, July 10, 2026