RSV Monoclonal Antibody

Respiratory Syncytial Virus (RSV) Monoclonal Antibody

According to the U.S. Centers for Disease Control and Prevention (CDC), respiratory syncytial virus (RSV) is a leading cause of respiratory disease in children. The European Medicines Agency (EMA) and the CDC say RSV monoclonal antibody (mAb) therapy prevents serious lower respiratory tract disease (LRTD) caused by RSV in newborns and young children during their first RSV season. The World Health Organization (WHO) published its preferred product characteristics of mAb therapy that delivers passive immunization against ‎RSV‎ disease.

In the United States, among mothers with an infant <8 months, 41.3% reported that their infant received nirsevimab as of March 2024.

RSV Monoclonal Antibody Therapy

AstraZeneca and Sanofi co-developed Beyfortus™ (Nirsevimab-alip), a U.S. FDA-approved single-dose, long-acting mAb designed to protect infants through their first and second RSV seasons. The European Commission granted Beyfortus worldwide approval on November 4, 2022, followed by approvals from the U.K., Canada, and the USA. 

Synagis® (Palivizumab) is a multi-dose injectable RSV antibody that provides one month of protection, requiring five injections to cover a typical RSV season. The U.S. FDA (1998), Canada, Japan, Israel, the U.K., and India (2023) have approved Synagis to protect at-risk infants against RSV.

Motavizumab is a discontinued investigational RSV mAb. MedImmune filed the original BLA in January 2008.

RSV Monoclonal Antibody Candidates

Merck's Clesrovimab (MK-1654) is an investigational extended half-life mAb developed as a passive immunization to prevent RSV-associated medically attended lower respiratory infection during their first RSV season. Merck announced on December 17, 2024, that the U.S. FDA had accepted the Biologics License Application for clesrovimab. The FDA has set a Prescription Drug User Fee Act date of June 10, 2025.

MK-1654-004 (NCT04767373) is a Phase 2b/3 double-blind, randomized, placebo-controlled study to evaluate the safety and efficacy of clesrovimab in healthy preterm and full-term infants. 105 mg/0.7 mL is administered as a single intramuscular injection and is the same for all infants regardless of weight.

Shanghai Ark Biopharmaceutical Co., Ltd. announced on November 23, 2023, that it had received IND approval in China from the National Medical Products Administration for a novel antibody, AK0610, targeting RSV. The drug is anticipated to protect infants throughout the entire RSV season. ArkBio licensed the drug's intellectual properties from the Institute of Microbiology, Chinese Academy of Sciences, Beijing Children's Hospital, Capital Medical University, and National Center for Children's Health.