A Prospective, Randomized, Open-label Phase 4 Study of the Immunology and Safety of Maternal RSV Vaccination (ABRYSVO (TM)), Infant Nirsevimab (BEYFORTUS (TM)) Immunization, or Both Products During the First Year of Life
Respiratory Syncytial Virus (RSV) is the leading cause of lower respiratory tract infections (LRTIs) in infants and young children. It is also a leading cause of mortality in children \<5 years of age worldwide. Until recently, no Food and Drug Administration (FDA)-approved vaccines were available to prevent RSV infection. The only prophylactic product for RSV prevention recommended for infants was the monoclonal antibody palivizumab, but administration was limited to those with extreme prematurity, chronic lung disease, or hemodynamically significant congenital heart disease. However, in 2023, the FDA approved two products designed to prevent RSV lower respiratory tract disease (LRTD) in all infants: an active RSV vaccine based on the prefusion F protein (RSVpreF, ABRYSVO, Pfizer) administered during pregnancy, and a passive, long-acting monoclonal antibody (nirsevimab-alip \[henceforth referred to as nirsevimab\], BEYFORTUS, AstraZeneca) administered to infants at birth or at the start of their first RSV season. Both products were evaluated in Phase 3 pivotal clinical trials and have high efficacy in preventing LRTD caused by RSV in infants. Although there is no established correlate of protection against RSV, antibodies have been associated with protection across multiple studies. The clinical development plan for the products did not include comprehensive evaluations of the magnitude and durability of the immune response, nor were the two products tested in a single trial. This study is a prospective, randomized, open-label Phase 4 study with the primary objective of evaluating the magnitude and durability of RSV-specific neutralizing antibodies in infants through 12 months of life following either maternal RSV vaccination, infant nirsevimab administration, or both products combined.
• 18-45 years of age at time of enrollment with an uncomplicated singleton pregnancy who are at no known increased risk for complications per clinical judgement of the investigator
• Understands and agrees to comply with all study procedures
• Willing and able to provide consent for study participation for themselves and their infant prior to initiation of any study procedures
• In good health, as determined by the medical history and clinical judgment of the investigator Note: Healthy volunteers with pre-existing stable disease, defined as disease not requiring significant change in therapy or hospitalization for worsening disease during the 6 weeks before enrollment, can be included.
• Intention to deliver at a hospital or birthing facility where study procedures can be performed
• Eligible to receive either product per the FDA package inserts. (Maternal RSVpreF from 32 0/7 to 36 6/7 weeks gestational age (GA) from September 1 to March 31)