Clesrovimab

China's National Medical Products Administration (NMPA) has approved two domestically developed long-acting monoclonal antibodies for the prevention of respiratory syncytial virus (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; formerly RB0026), developed by Reyoung (Shandong) Biopharmaceutical Co., Ltd. (Reyoung Bio), and retavibart, developed by Zhuhai Trinomab Pharmaceutical Co., Ltd. (Trinomab; SSE STAR Market: 688806). Culevibart 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. Simcere Pharmaceutical Group Limited (HKEX: 02096) holds exclusive commercialization rights for culevibart across Greater China under a strategic partnership with Reyoung Bio 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. Retavibart, 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 describes the product as a long-acting fully human monoclonal antibody capable of providing protection for up to nine months following a single injection. 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). Culevibart is a recombinant human IgG1κ monoclonal antibody targeting epitope II of the RSV F protein. 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 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 also targets the RSV F protein 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 has positioned the antibody for use in both healthy and high-risk infants. 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, the approval also increases the potential partnering value of culevibart outside Greater China. Simcere's agreement covers commercialization only in Greater China, and no ex-China commercialization partner for culevibart has been publicly disclosed. Spot something wrong? Report an issue with this article