Pfizer’s Abrysvo meets primary Phase 3 endpoint in RSV disease

Pfizer announced positive top-line immunogenicity and safety data from the ongoing pivotal Phase 3 clinical trial MONeT, evaluating a single dose of Abrysvo versus placebo in adults 18 to 59 years of age at risk of developing severe respiratory syncytial virus – RSV -associated lower respiratory tract disease, or LRTD. Adults with certain underlying chronic conditions are at increased risk of developing, and being hospitalized for, RSV-associated LRTD. No RSV vaccines have been approved for use in adults 18 to 59 years of age. The MONeT study achieved its co-primary immunogenicity endpoints and primary safety endpoint. Participants demonstrated RSV-A and RSV-B subgroup neutralizing responses non-inferior to the response seen in the Phase 3 RENOIR study of Abrysvo in more than 34,000 adults aged 60 or older where vaccine efficacy was previously demonstrated. Participants also achieved at least a four-fold increase in serum neutralizing titers for RSV-A and RSV-B one month following receipt of Abrysvo compared to pre-vaccination. During the trial, Abrysvo was well-tolerated, and safety findings were consistent with those from previous investigations of Abrysvo in other populations. Pfizer intends to submit these data to regulatory agencies and request expansion of the age group from the current indication to 18 years of age and older. The company also intends to publish these findings in a peer-reviewed scientific journal and share them at an upcoming scientific conference.