China Approves Silevimig, the World's First Bispecific Antibody for Rabies Passive Immunization
Key Insights
China's NMPA approved Silevimig Injection (search) (GR1801), the world's first fully human bispecific antibody targeting dual epitopes of the rabies (search) virus, on June 22, 2026.
The drug demonstrated non-inferior protective efficacy compared with human rabies immune globulin (search) (HRIG) in a Phase III adult trial, without compromising vaccine-induced active immunity.
Silevimig offers the smallest injection volume among rabies (search) passive immunization products, carries no blood-borne infection risk, and can be manufactured at scale with standardized processes.
China's National Medical Products Administration (search) (NMPA) has approved Silevimig Injection (search) (GR1801), a Class 1 therapeutic biological product developed as the world's first fully human bispecific antibody for passive immunization against rabies (search). The approval, announced by China Medical System Holdings Limited (search) (CMS) on June 22, 2026, marks a significant advance in post-exposure prophylaxis for a disease that carries a case-fatality rate approaching 100% once clinical symptoms manifest.
Silevimig Injection (search) is indicated for passive immunization in adults following rabies (search) virus (RABV) exposure. The product targets dual epitopes — epitopes I and III — of the viral envelope glycoprotein (G protein), blocking the virus's interaction with host receptors and neutralizing RABV before active vaccination can establish full protection.
A Novel Mechanism Aligned with WHO Recommendations
The bispecific antibody approach is consistent with the World Health Organization's recommendation for a "cocktail" therapeutic paradigm against rabies (search). By binding to two distinct epitopes simultaneously, Silevimig demonstrates broad neutralization capability against different viral strains and genotypes of RABV, providing immediate protection during the critical window before vaccine-induced antibodies reach protective levels — a process that typically requires one to two weeks after the first vaccine dose.
As a recombinant, fully human antibody, Silevimig carries no risk of blood-borne infections, exhibits low immunogenicity, and shows minimal interference with the active immune response induced by concurrent rabies (search) vaccination. These characteristics address key limitations of human rabies immune globulin (search) (HRIG), the current standard passive immunization product in China, which must be sourced from healthy donors, making supply difficult and costly while carrying potential blood-borne pathogen risks.
Phase III Clinical Evidence
In a pivotal Phase III clinical trial conducted in adults, Silevimig met its primary efficacy endpoint, demonstrating non-inferior protective efficacy compared with HRIG. The study confirmed that the product provides immediate protection during the early stages of rabies (search) virus exposure without compromising the active immune response induced by vaccination. A separate Phase III clinical trial in children and adolescents aged 2 to less than 18 years is currently ongoing in China.
Silevimig also offers practical advantages in clinical administration. It is described as the passive immunization product with the smallest dose for rabies (search), resulting in less injection volume and easier administration — factors that can reduce patient pain and improve compliance.
Addressing a Significant Unmet Need
The rabies (search) burden in China remains substantial. According to the Chinese Center for Disease Control and Prevention, more than 40 million people are exposed to rabies annually, with approximately 40% falling under Category III exposure — the most severe classification requiring both vaccination and passive immunization. However, only about 15% of Category III cases currently receive passive immunization, a gap driven by limited awareness, high cost, and restricted accessibility of existing products.
Standardized post-exposure management — comprising wound care, vaccination, and passive immunization when indicated — remains the most effective strategy against rabies (search), for which no proven treatment exists once clinical symptoms appear.
Commercialization and Pipeline Impact
CMS obtained exclusive commercialization rights for Silevimig in mainland China, along with exclusive licensing rights for the rest of the Asia-Pacific region, the Middle East, and North Africa, through an Exclusive Collaboration Agreement signed in September 2025 with Chongqing Genrix Biopharmaceutical Co., Ltd. (search) The collaboration term extends until ten years after marketing approval in mainland China, with automatic renewal for successive ten-year periods.
The approval expands CMS's commercialized innovative drug portfolio to eight products, with six additional innovative drugs under marketing review and approximately 20 projects advancing through clinical development. The company stated that its innovation transformation strategy has "fully entered the value-harvesting phase," with the commercialization rollout of Silevimig expected to provide sustained momentum to performance growth.