In February 2024 Pfizer announced top-line ABRYSVO vaccine efficacy and safety data from the ongoing Phase III RENOIR (RSV vaccine Efficacy study iN Older adults Immunised against RSV disease). The trial investigates ABRYSVO in adults aged 60 and above. ABRYSVO is a bivalent vaccine designed to provide broad protection against all RSV-LRTD, “regardless of the virus subgroup”. The basis is the RSV fusion protein (F) in the prefusion conformation, a major target of virus infection blocking antibodies.
Vaccine efficacy
Vaccine efficacy against RSV-associated lower respiratory tract disease (LRTD), which is defined by three or more symptoms, after disease surveillance in season two was 77.8%. Vaccine efficacy after season one was 88.9%, demonstrating “durable efficacy” after two seasons. Furthermore, “consistent” efficacy was demonstrated for both RSV A and RSV B after season two; vaccine efficacy against each subtype was ≥ 80% for LRTD with three or more symptoms.
Vaccine efficacy was also sustained against less severe LRTD, defined by two or more symptoms, from 65.1% after season one to 55.7% after the end of season two. For RSV-associated LRTD vaccine efficacy across both seasons was 81.5%. No new adverse events were reported through the second RSV season beyond reports from the first season.
Dr Annaliesa Anderson, Senior Vice President and Chief Scientific Officer, Vaccine Research and Development, Pfizer, is “encouraged by the level of protection” observed after “two full RSV seasons”.
“These new data indicate that broad and durable protection against both types of RSV that cause disease, RSV A and RSV B, is the potential benefit to having a bivalent vaccine.”
We look forward to hearing more from Pfizer on their efforts against RSV at the Congress in Washington this April. Joining us there are senior representatives of the team, including Dr Anderson, so get your tickets to learn more, and don’t forget to subscribe to our weekly newsletters here.
