CMS has announced that the new drug application for its Class 1 therapeutic biologic, Sileweimimab (GR1801) Injection, has been approved by China's National Medical Products Administration. The drug registration certificate was obtained on June 22, 2026. The product, branded as Jinsuxi®, is indicated for passive immunization in adults exposed to the rabies virus.
Sileweimimab Injection is a recombinant fully human bispecific antibody targeting the rabies virus. It binds to epitopes I and III of the viral envelope glycoprotein (G protein), blocking its interaction with cellular receptors and specifically neutralizing the rabies virus before the active immunity from a vaccine becomes fully protective. This product is the world's first bispecific antibody for rabies passive immunization. Its molecular design aligns with the "cocktail" combination formulation recommended by the World Health Organization to ensure efficacy against different viral strains or genotypes.
The product's Phase III clinical trial in China for adults met its primary efficacy endpoint. The study demonstrated that the product offers non-inferior protective efficacy compared to Human Rabies Immune Globulin, which is the primary passive immunization agent currently used in China. It provides immediate protection during the early stages of rabies virus exposure without adversely affecting the vaccine-induced active immune response. Furthermore, a separate Phase III clinical trial for children and adolescents aged 2 to under 18 is currently underway in China. The product holds authorized patents in China.
Understanding the Disease and Market Need
Rabies is an acute zoonotic disease caused by rabies virus infection, with clinical symptoms often including specific hydrophobia, aerophobia, pharyngeal muscle spasms, and progressive paralysis, and is almost 100% fatal. There is currently no recognized effective treatment once symptoms appear, making standardized post-exposure prophylaxis the most effective strategy. This involves wound management, vaccination, and administration of passive immunization agents as needed. It takes 1-2 weeks for a vaccine to induce antibody production; passive immunization agents provide immediate protection during this window, from the first vaccine dose until sufficient antibodies are produced.
According to China's "Rabies Exposure Prevention and Treatment Work Specification (2023 Edition)," passive immunization treatment should be administered concurrently with the first vaccine dose for Category III exposures and for Category II exposures in individuals with severe immune deficiency. China sees over 40 million rabies virus exposures annually, with 40% classified as Category III. However, due to factors like patient awareness, cost, and accessibility, only about 15% of Category III exposures receive passive immunization injections. The primary rabies passive immunization agent in China is HRIG. However, HRIG is sourced from human plasma, leading to supply limitations, high cost, and potential blood-borne infection risks, which contribute to the current low penetration rate of passive immunization agents in China.
Product Advantages and Commercial Outlook
The company is focused on developing differentiated innovative products. The rabies passive immunization market is vast, yet current agents have low market penetration and limitations in safety and accessibility. Sileweimimab Injection is the world's first fully human bispecific antibody targeting two rabies virus epitopes. It conforms to WHO development recommendations, allows for large-scale standardized stable production, and offers broad neutralizing coverage, low immunogenicity, minimal interference with vaccine-induced immunity, and controllable costs. Additionally, it is currently the lowest-dose rabies passive immunization agent, requiring less volume for injection, which can reduce patient pain and improve compliance.
The approval of this product is expected to provide a new treatment option for patients in China requiring urgent post-exposure rabies management. It will synergize effectively with the company's existing expert network and market resources and is anticipated to have a positive impact on the group's financial performance.
In September 2025, the group, through a subsidiary, entered into an exclusive cooperation agreement with Chongqing Zhixiang Jintai Biological Pharmaceutical Co., Ltd. for the product. Under this agreement, the group secured exclusive commercialization rights for the product in mainland China and exclusive licensing rights for the Asia-Pacific region (excluding mainland China), the Middle East, and North Africa. The cooperation term lasts for ten years following the product's approval in mainland China (the initial term). After the initial term, the agreement will automatically renew for successive ten-year periods unless terminated or dissolved under conditions specified in the agreement. The group will proceed with the commercialization of the product in an orderly manner to provide a new choice for rabies passive immunization to patients as soon as possible.