China approves two homegrown long-acting RSV antibodies for infants, challenging Beyfortus
核心洞察
China's NMPA approved two domestically developed long-acting RSV monoclonal antibodies, culevibart (搜索) (Yingmule) and retavibart (搜索), on September 3 for preventing RSV-caused lower respiratory tract infections in infants.
Culevibart (搜索) reduced medically attended RSV LRTI by 85.32% and RSV-related hospitalizations by 83.27% versus placebo at 150 days in a pivotal Phase III trial.
Simcere Pharmaceutical Group (搜索) holds exclusive Greater China commercialization rights for culevibart (搜索) under a partnership with Reyoung Bio (搜索) announced just two weeks before approval.
China's National Medical Products Administration (NMPA) has approved two domestically developed long-acting monoclonal antibodies for the prevention of respiratory syncytial virus (搜索) (RSV)-caused lower respiratory tract infections (LRTI) in infants, opening the market to new homegrown competition against established imported prophylactic antibodies.
The September 3 approvals covered Yingmule (culevibart (搜索); formerly RB0026), developed by Reyoung (Shandong) Biopharmaceutical Co., Ltd. (Reyoung Bio (搜索)), and retavibart (搜索), developed by Zhuhai Trinomab (搜索) Pharmaceutical Co., Ltd. (Trinomab; SSE STAR Market: 688806).
Culevibart: A China-Originated Long-Acting Antibody
Culevibart (搜索) was approved for newborns and infants born at or after 35 weeks of gestational age who are entering or born during their first RSV epidemic season. The label excludes children with chronic lung disease (CLD), including bronchopulmonary dysplasia (BPD), or clinically significant congenital respiratory abnormalities.
Culevibart (搜索) is a recombinant human IgG1κ monoclonal antibody targeting epitope II of the RSV F protein (搜索). Fc segment engineering extends its serum half-life, allowing seasonal protection from a single intramuscular injection.
In a pivotal Phase III multicenter, randomized, double-blind, placebo-controlled study, culevibart (搜索) reduced medically attended RSV LRTI by 85.32% versus placebo at 150 days after dosing and reduced RSV-related hospitalizations by 83.27%. At 240 days, efficacy against medically attended LRTI remained at 82.04%, while efficacy against hospitalization was 78.44%. A Phase IIIb study in infants and toddlers aged one to two years is ongoing to support a potential label expansion.
Retavibart: A Second Homegrown Option
Retavibart (搜索), formerly known as TNM001, was approved for the prevention of RSV-caused LRTI in newborns and infants entering or born during their first RSV season. Trinomab (搜索) describes the product as a long-acting fully human monoclonal antibody capable of providing protection for up to nine months following a single injection.
Retavibart (搜索) also targets the RSV F protein (搜索) and advanced rapidly through China's regulatory process in 2026. Its new drug application was accepted in February before the NMPA Center for Drug Evaluation granted priority review in March. Trinomab (搜索) has positioned the antibody for use in both healthy and high-risk infants.
Simcere's Commercialization Role
Simcere Pharmaceutical Group (搜索) Limited (HKEX: 02096) holds exclusive commercialization rights for culevibart (搜索) across Greater China under a strategic partnership with Reyoung Bio (搜索) announced on August 20, 2026, just two weeks before the approval. Reyoung Bio remains the regulatory applicant. The agreement gives Simcere its first RSV prophylaxis product in China.
The transaction is structured as a commercialization license rather than a co-development arrangement. Reyoung retains responsibility for ongoing clinical development, while Simcere takes responsibility for commercialization and market access across Greater China. The arrangement allows Reyoung to leverage the larger drugmaker's established anti-infectives commercial infrastructure as culevibart (搜索) approaches a potential launch.
A Shifting Competitive Landscape
Both products are designed to provide passive immune protection through an entire RSV season following a single administration, putting them in competition with established long-acting RSV antibodies including Sanofi and AstraZeneca's nirsevimab (Beyfortus) and Merck's clesrovimab (Enflonsia).
If approved, culevibart (搜索) could become China's first domestically developed long-acting RSV preventive antibody, according to the companies, providing a local competitor to Beyfortus. Both antibodies target the RSV F protein (搜索) and are designed to provide protection across an RSV season following a single administration. Beyfortus received NMPA approval in December 2023 and launched in China in January 2024, meaning culevibart would enter an established therapeutic category currently dominated by an imported product.
The simultaneous approvals significantly broaden China's RSV prevention landscape, which had previously relied heavily on multinational products. Nirsevimab, developed by Sanofi and AstraZeneca, is approved in major global markets, while Merck's clesrovimab, FDA-approved in June 2025, has reported durable Phase III efficacy extending into a second RSV season.
For Reyoung Bio (搜索), the approval also increases the potential partnering value of culevibart (搜索) outside Greater China. Simcere's agreement covers commercialization only in Greater China, and no ex-China commercialization partner for culevibart has been publicly disclosed.