HBM HOLDINGS-B - VOLUNTARY ANNOUNCEMENT - NMPA ACCEPTANCE OF IND APPLICATION FOR HBM7004

FOR THE TREATMENT OF ADVANCED SOLID TUMORS

和鉑醫藥控股有限公司

HBM Holdings Limited

(incorporated in the Cayman Islands with limited liability)

(Stock Code: 02142)

VOLUNTARY ANNOUNCEMENT

NMPA ACCEPTANCE OF IND APPLICATION FOR HBM7004

FOR THE TREATMENT OF ADVANCED SOLID TUMORS

This announcement is made by HBM Holdings Limited (the "Company", together with its subsidiaries, the "Group") on a voluntary basis to inform the shareholders and potential investors of the Company about the latest business update of the Group.

The board of directors of the Company (the "Board") is pleased to announce that the National Medical Products Administration of China (the "NMPA") has accepted the Investigational New Drug ("IND") application for HBM7004, a novel B7H4xCD3 bispecific antibody, for the treatment of advanced solid tumors. This follows the Group's recent receipt of clearance of its IND application from the Food and Drug Administration of the United States to initiate a first-in-human Phase I clinical trial in the U.S. for HBM7004, as disclosed in the Company's announcement dated 8 May 2026.

About HBM7004

HBM7004 is a novel B7H4xCD3 bispecific antibody developed using the Group's proprietary HBICE® platform. This bispecific antibody is designed to provide a differentiated approach to cancer immunotherapy with the potential to enhance both efficacy and safety. The development of HBM7004 further demonstrates the versatility and plug-and-play advantages of the HBICE® platform.

In preclinical studies, HBM7004 demonstrated intratumor B7H4-dependent T-cell activation. In multiple animal models, HBM7004 showed strong anti-tumor efficacy, remarkable in vivo stability, and reduced systemic toxicity. Additionally, in preclinical models, HBM7004 exhibited a strong synergistic effect when combined with a B7H4x4-1BB bispecific antibody at a low effector-to-target cell ratio, indicating an encouraging therapeutic window.

Cautionary Statement: We cannot guarantee that we will be able to successfully develop or ultimately market HBM7004. Shareholders and potential investors of the Company are advised to exercise due care when dealing in the shares of the Company.

By order of the Board

HBM Holdings Limited Dr. Jingsong Wang

Chairman and Executive Director

Hong Kong, 10 June 2026