Clinical Trials Arena

Pfizer reports top-line results from Phase III RSV vaccine trial

The vaccine showed a 77.8% efficacy against RSV-associated LRTD after the second season.

Pfizer has reported top-line results from the Phase III RENOIR clinical trial of its respiratory syncytial virus (RSV) vaccine, ABRYSVO, for RSV-linked lower respiratory tract disease (LRTD).

The randomised, placebo-controlled, and double-blinded study evaluated the safety, immunogenicity, and efficacy of a single dose of the vaccine in adults aged 60 and above.

It enrolled subjects following a second RSV season in the Northern and Southern Hemispheres.

According to the findings, the vaccine showed a 77.8% efficacy against RSV-associated LRTD after the second season, a slight decrease from the 88.9% efficacy observed after the first season, indicating durable protection.

Efficacy was consistent for both RSV A and RSV B subtypes, with rates of more than 80% for LRTD with three or more symptoms.

The vaccine's efficacy was demonstrated to be maintained against less severe LRTD, defined by two or more symptoms, from 65.1% after the first season to 55.7% after season two.

Following more than 16.4 months of disease surveillance across both seasons, the vaccine's efficacy against RSV-associated LRTD with three or more symptoms was 81.5%.

Pfizer reported no new adverse events through the second RSV season other than those reported during the first season, indicating ABRYSVO's favourable safety profile.

The company plans to submit these findings to regulatory agencies and vaccine technical committees for review.

Pfizer Vaccine Research and Development senior vice-president and chief scientific officer Annaliesa Anderson said: “We are encouraged by the level of protection that we observed after two full RSV seasons for ABRYSVO.

“This new data indicates 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.”

The latest development comes after Pfizer’s Elrexfio for treating multiple myeloma received conditional market approval from the European Commission (EC), following a Phase II trial in patients who had previously undergone multiple treatments.