Pfizer posts positive data for maternal RSV vax

Nov. 2, 2022

Pfizer announced positive top-line data from the phase 3 trial investigating its bivalent RSV prefusion vaccine candidate when administered to pregnant participants to help protect their infants from RSV disease after birth.

If approved, Pfizer’s vaccine candidate — RSVpreF or PF-06928316 — would be the first maternal vaccine available to help prevent the common and potentially life-threatening respiratory illness in young infants.

According to the drugmaker, the pre-planned, interim efficacy analysis conducted by an external and independent data monitoring committee for the MATISSE trial met the success criterion for one of two primary endpoints. Vaccine efficacy of 81.8% was observed against severe medically attended lower respiratory tract illness due to RSV in infants from birth through the first 90 days of life, with high efficacy of 69.4% demonstrated through the first six months of life.

Although the statistical success criterion was not met for the second primary endpoint — efficacy in infants from birth through the first 90 days of life — the data monitoring committee said the 57.1% efficacy was 'clinically meaningful. '

Based on these positive results, Pfizer says it plans to submit a BLA to the FDA by the end of 2022 for the vaccine candidate, followed by other regulatory authorities in the coming months.

The race has been on to get approval for vaccines against the deadly virus and drugmakers are coming at it from all angles. Back in August, Pfizer announced positive top-line results of an interim analysis for another phase 3 clinical trial testing the same vaccine  — RSVpreF — in adults ages 60 years or older. Last month, GSK announced positive phase 3 trial results for its RSV vaccine candidate for adults aged 60 years and above. Sanofi and AstraZeneca's jointly developed vaccine, nirsevimab, which is designed to protect infants from RSV, is already in the hands of regulators.