Shanghai Henlius Biotech, Inc. (2696) entered into a license agreement with Eisai Co., Ltd. on February 5, 2026, granting Eisai the rights to develop, manufacture, and commercialize HANSIZHUANG (serplulimab injection) for oncology in Japan.

Under the agreement, Eisai will pay an upfront fee of US$75 million, regulatory milestone payments up to US$80.01 million, commercial sales milestone payments up to US$233.33 million, and double-digit royalties on annual net sales. The agreement remains in effect until five years after the expiration of the Royalty Term, which runs from the first commercial sale of HANSIZHUANG in Japan to the latest of: 10 years from the first commercial sale, the expiration of regulatory marketing exclusivity, or patent validity covering the product compound in Japan.

HANSIZHUANG is an anti-PD-1 monoclonal antibody approved in Mainland China for several indications in lung cancer and esophageal squamous cell carcinoma, and has obtained marketing authorizations in multiple countries and regions. It has also received orphan-drug designations from drug regulatory authorities in the United States, the European Union, Switzerland, and other regions. According to the announcement, global sales of monoclonal antibody drugs targeting PD-1 reached approximately US$45.7 billion in 2024.

The collaboration with Eisai is intended to further strengthen the product’s global accessibility and potentially increase Shanghai Henlius Biotech’s revenue. Eisai, listed on the Tokyo Stock Exchange (4523), focuses on researching, developing, manufacturing, and selling pharmaceuticals in neuroscience and oncology.