Biopharmaceutical company Pfizer Inc (NYSE: PFE) on Monday reported encouraging top-line results from a Phase 3 clinical trial evaluating its ABRYSVO vaccine for respiratory syncytial virus (RSV) in immunocompromised adults aged 18 and older. The trial demonstrated that a single dose of ABRYSVO was well-tolerated and elicited strong neutralizing responses, providing robust immune protection against RSV-A and RSV-B subtypes. This adds to evidence supporting ABRYSVO's efficacy in high-risk adults, building on previous studies that showed similar results in adults aged 60 and older.

Substudy B of the MONeT trial (NCT05842967) assessed the vaccine's safety and immunogenicity across four groups of immunocompromised adults: non-small cell lung cancer patients, hemodialysis patients with end-stage renal disease, patients with autoimmune inflammatory disorders on immunomodulators, and solid organ transplant recipients. Among the 203 participants, ABRYSVO exhibited a favorable safety profile consistent with earlier findings, and the vaccine's 120 µg dose generated strong neutralizing responses across all age groups.

Pfizer intends to present these findings at a scientific conference, publish them in a peer-reviewed journal and submit the data to regulatory agencies. The results bolster ABRYSVO's profile, aligning with data presented in June 2024 at the Advisory Committee on Immunization Practices (ACIP) meeting. In a related study, 681 adults with chronic conditions demonstrated RSV subgroup neutralizing responses comparable to the Phase 3 RENOIR study.

The US Food and Drug Administration has also approved Pfizer's ACT-O-VIAL presentation of ABRYSVO, facilitating easier reconstitution with a compact, dual-component system designed for safety and storage efficiency. This approval introduces a new option alongside Pfizer's needle-free reconstitution kits.

ABRYSVO is the first RSV vaccine approved for both older adults and maternal immunization to protect infants. The US FDA approved the vaccine in May 2023 for preventing RSV-associated lower respiratory tract disease (LRTD) in individuals aged 60 and older. In August 2023, the FDA extended approval for maternal immunization, with recommendations for seasonal administration from September to January. The European Medicines Agency granted marketing authorization in August 2023, followed by approvals in Argentina, the United Kingdom, Canada, Macau, Japan and Australia.

Beyond the MONeT trial, Pfizer is evaluating ABRYSVO in children aged two to less than 18 years who are at higher risk for RSV. Pfizer's commitment to scientific advancement aims to deliver therapies that enhance quality of life and improve global health outcomes, working in collaboration with healthcare providers, governments, and communities worldwide.