Vaccine Info

RSV preF - Pfizer RSV Vaccine

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Last reviewed
September 2, 2021
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RSVpreF - Pfizer RSV Vaccine Description

Pfizer Inc.'s RSVpreF vaccine candidate is based on the prefusion form of the RSV fusion protein. The vaccine is designed to stimulate the production of serum anti-F immunoglobulin G in the mother, which can then be transferred to the fetus across the placenta and protect for the first six months of life when the risk of hospitalization is highest.

Pfizer’s respiratory syncytial virus bivalent prefusion F subunit investigational vaccine candidate (RSVpreF) vaccine candidate builds on foundational basic science discoveries, including those made at the US National Institutes of Health (NIH), which detailed the crystal structure of a key viral protein that RSV uses to attack human cells. In addition, they showed that the antibodies that protect humans from RSV target one form of this viral protein. Applying insights from this important work, Pfizer engineered and tested numerous candidates and identified those that elicited a strong and stable immune response in pre-clinical evaluation, leading to the vaccine candidate Pfizer is evaluating in human trials.

In November 2018, the U.S. FDA granted Fast Track status to RSVpreF to prevent RSV-associated lower respiratory tract illness in infants by active immunization of pregnant women.

In a Phase 2 Efficacy study, Pfizer reported the RSV vaccine showed 100% observed efficacy against mild to moderate RSV illness in adults (N=62); Performance vs. benchmark: Ad26.RSV preF vaccine showed 52% observed efficacy in the same human challenge model; No vaccine-related serious adverse events; most frequent mild adverse event was injection site pain.

“RSV is a significant cause of severe respiratory disease in older adults, and it can cause disability and death. There is an important unmet medical need for an effective vaccine that can help protect older adults against this highly contagious disease,” commented Kathrin U. Jansen, Ph.D., SVP, and Head of Vaccine Research & Development at Pfizer Inc., in a press statement issued on September 2, 2021. “The start of this Phase 3 study (RENOIR) is an important step forward towards our goal of comprehensive immunization against RSV disease, which includes developing a potential first vaccine to help prevent RSV disease in adults as well as the ongoing efforts to help protect infants through maternal immunization, subject to regulatory approval of the candidate vaccine.”

New York-based Pfizer Inc.'s (NYSE: PFE) portfolio includes medicines and vaccines and many of the world's best-known consumer health care products. 

RSVpreF - Pfizer RSV Vaccine Indication

RSVpreF is indicated to prevent RSV infections in both infants and adults, says Pfizer.

Globally, there are an estimated 33 million cases of RSV annually in children less than 5 years of age, with about 3 million hospitalized and up to approximately 120,000 dying each year from complications associated with the infection. About half of the pediatric hospitalizations and deaths occur in infants less than 6 months of age. In addition, it is estimated that in the United States, approximately 177,000 older adults are hospitalized annually because of RSV, says the U.S. CDC.

A study published by the NEJM on July 30, 2021, concluded by saying 'RSV F protein nanoparticle vaccination in pregnant women did not meet the prespecified success criterion for efficacy against RSV-associated, medically significant lower respiratory tract infection in infants up to 90 days of life.'

RSVpreF - Pfizer RSV Vaccine News

September 2, 2021 - Pfizer Inc. announced the initiation of RENOIR (RSV vaccine Efficacy study iN Older adults Immunized against RSV disease), a Phase 3 clinical trial evaluating the efficacy, immunogenicity, and safety of a single dose of its respiratory syncytial virus (RSV) bivalent prefusion F subunit investigational vaccine candidate (RSVpreF) in adults ages 60 years or older.

July 30, 2021 - Pfizer announced a challenge study, where vaccines were given to 62 adults under 50, who were then intentionally infected with RSV to see if the shot worked, showed “100% observed efficacy against mild to moderate symptomatic infection resulting from RSV.”  

June 22, 2020 - Pfizer Announces start of (4) Phase 3 Clinical Trials. One study (NCT04424316) of the respiratory syncytial virus (RSV) vaccine candidate, RSVpreF, in pregnant women to evaluate the safety and efficacy of RSVpreF in infants born to immunized pregnant women as compared to placebo.

May 22, 2018 - Pfizer Inc. announced that it had started a Phase 1/2 trial of its respiratory syncytial virus vaccine candidate in healthy adult volunteers. The highest risk of severe outcome from RSV occurs in the first months of life.

RSVpreF - Pfizer RSV Vaccine Clinical Trials

RSV preF is currently being tested in several clinical trials.

This ClinicalTrials.gov Identifier: NCT04424316 Phase 3, multicenter, randomized, double-blinded, placebo-controlled study to assess the efficacy, safety, and immunogenicity of RSVpreF or placebo (1:1 randomization) in infants born to healthy women vaccinated during pregnancy, as well as the safety and immunogenicity in the pregnant women. This will be a global study that will span multiple RSV seasons—last Update Posted: August 20, 2021.

The Phase 3 RENOIR trial of RSVpreF is a global, randomized, double-blind, placebo-controlled study that expects to enroll approximately 30,000 participants 60 years and older. The study's primary objectives will assess safety and efficacy for the prevention of moderate to severe lower respiratory tract illness (msLRTI-RSV) during the first RSV season.