Shares of Alphamab-B (09966) have surged more than 10%, climbing 10.43% to HK$8.15 by the time of writing, with a trading turnover of HK$5.97 million.

The rally follows news that the company's self-developed HER2 bispecific antibody, Enhertu® (Anituo Monoclonal Antibody Injection, R&D code: KN026), co-developed with Shanghai Jinmante Biotechnology Co., Ltd., a wholly-owned subsidiary of CSPC Pharmaceutical Group, has received Breakthrough Therapy Designation from the Center for Drug Evaluation (CDE) of China's National Medical Products Administration (NMPA). The designation is for the first-line treatment of unresectable or metastatic HER2-positive adult breast cancer in combination with CSPC's docetaxel (albumin-bound) (HB1801).

This marks the second Breakthrough Therapy Designation for Enhertu®, following its previous designation for HER2-positive gastric cancer (including gastroesophageal junction adenocarcinoma).

It is reported that Enhertu® received formal approval for its gastric cancer indication in May 2026, making it the first commercially available, domestically developed HER2 bispecific antibody in China. This approval represented a significant breakthrough for local innovation in the bispecific antibody field.

The company stated that this latest Breakthrough Therapy Designation will accelerate the research, development, and regulatory review process for Enhertu®'s advanced breast cancer indication. Following the commercialization of the gastric cancer indication, the rapid advancement of the breast cancer indication is expected to fully unlock the clinical value and commercial potential of Enhertu®, continuously expanding the product's growth prospects.