复宏汉霖HLX3902在中国内地完成1期临床首例患者给药

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Hong Kong Exchanges and Clearing Limited and The Stock Exchange of Hong Kong Limited take no responsibility
for the contents of this announcement, make no representation as to its accuracy or completeness and expressly
disclaim any liability whatsoever for any loss howsoever arising from or in reliance upon the whole or any part of the
contents of this announcement.
Shanghai Henlius Biotech, Inc.
ʮ̡
(A joint stock company incorporated in the People ’s Republic of China with limited liability)
(Stock code: 2696)
VOLUNTARY ANNOUNCEMENT
THE FIRST PATIENT HAS BEEN DOSED IN A PHASE 1 CLINICAL STUDY
OF HLX3902 INJECTION (STEAP1 ×CD3×CD28 TRISPECIFIC ANTIBODY)
FOR THE TREATMENT OF METASTATIC CASTRATION-RESISTANT
PROSTATE CANCER AND OTHER ADVANCED SOLID TUMORS IN
CHINESE MAINLAND
A. INTRODUCTION
This announcement is made by Shanghai Henlius Biotech, Inc. (the “Company ”) on a
voluntary basis to inform the shareholders and potential investors of the Company about the
latest business development of the Company.
The board of directors of the Company (the “Board ”) is pleased to announce that, recently,
the first patient has been dosed in the phase 1 clinical study of HLX3902 injection
(STEAP1 ×CD3×CD28 trispecific antibody) ( “HLX3902 ”), independently developed by the
Company, for the treatment of metastatic castration-resistant prostate cancer (mCRPC) and
other advanced solid tumors in Chinese Mainland (excluding Hong Kong, Macau and Taiwan
regions, the same as below). The Company intends to further commence the relevant clinical
trial in Australia upon fulfilment of the requisite conditions.
B. CLINICAL TRIAL DESIGN AND OBJECTIVES
This is an open-label, first-in-human (FIH) phase 1a clinical trial to evaluate the safety,
tolerability, pharmacokinetics, and preliminary efficacy of HLX3902 in patients with
metastatic castration-resistant prostate cancer (mCRPC) and other advanced solid tumors. The
study includes eight dose levels ranging from 0.005mg to 1.5mg, with each treatment cycle
lasting 4 weeks. The 0.005mg dose cohort employs an accelerated titration design, while the
remaining seven dose cohorts use a “3+3” dose-escalation design. The primary objectives of
this study are to evaluate the safety and tolerability of HLX3902 in patients with metastatic
castration-resistant prostate cancer (mCRPC) and other advanced solid tumors, and to
determine its maximum tolerated dose (MTD). The primary endpoints are the incidence of
dose-limiting toxicities (DLT) and the maximum tolerated dose (MTD) of HLX3902.

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C. ABOUT HLX3902
HLX3902 is a trispecific antibody drug independently developed by the Company,
intended for the treatment of metastatic castration-resistant prostate cancer (mCRPC) and
other advanced solid tumors. HLX3902 is a trispecific T-cell engager (TCE) antibody
that concurrently targets STEAP1, CD3, and CD28. Through engaging CD3 and CD28 to
redirect and enhance cytotoxic T cell responses to lyse STEAP1-expressing tumor cells
while increasing T cell activation, proliferation, and survival via optimization of “Signal
1” (CD3) and “Signal 2 ” (CD28), HLX3902 can achieve the purpose of treating metastatic
castration-resistant prostate cancer (mCRPC) and other advanced solid tumors. Preclinical
studies have demonstrated that HLX3902 exhibits good anti-tumor efficacy and safety, and
is expected to provide clinical benefits. In May and June 2026, HLX3902 was approved
to initiate phase 1 clinical trials in Australia and China, respectively, for the treatment of
metastatic castration-resistant prostate cancer (mCRPC) and other advanced solid tumors.
D. MARKET CONDITION
As of the date of this announcement, no trispecific antibody targeting STEAP1, CD3 and
CD28 has been approved globally.
WARNING STATEMENT WITH REFERENCE TO THE REQUIREMENTS UNDER RULE
18A.05 OF THE RULES GOVERNING THE LISTING OF SECURITIES ON THE STOCK
EXCHANGE OF HONG KONG LIMITED: The Company cannot guarantee the successful
development and commercialization of HLX3902. Shareholders and potential investors of the
Company are advised to exercise caution when dealing in the shares of the Company.
On behalf of the Board
Shanghai Henlius Biotech, Inc.
Wenjie Zhang
Chairman
Hong Kong, 30 July 2026
As at the date of this announcement, the board of directors of the Company comprises Mr. Wenjie
Zhang as the chairman and non-executive director, Dr. Jun Zhu as the executive director, Mr. Qiyu
Chen, Mr. Yuqing Chen, Ms. Xiaohui Guan, Dr. Yi Liu and Dr. Xingli Wang as the non-executive
directors, and Mr. Tak Young So, Dr. Lik Yuen Chan, Dr. Ruilin Song and Mr. Yihao Zhang as the
independent non-executive directors.