Vaccine Info

Pfizer RSVpreF RSV Vaccine

Authored by
Staff
Last reviewed
May 1, 2022
Share

Pfizer RSVpreF RSV Vaccine News For 2022

Pfizer Inc.'s RSVpreF bivalent vaccine candidate (PF-06928316) is based on the crystal structure of prefusion F, a key form of the viral fusion protein (F) that RSV uses to attack human cells. The vaccine candidate is composed of two preF proteins selected to optimize protection against RSV A and B. In addition, 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 phase 3 clinical trials.

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 U.S. National Institutes of Health (NIH), which detailed the crystal structure of a key viral protein that RSV uses to attack human cells.

For infants, RSVpreF 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. For seniors (60 yr.+), the vaccine is to prevent lower respiratory tract disease caused by RSV.

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. Then on March 2, 2022, the FDA granted Breakthrough Therapy Designation to prevent RSV-associated lower respiratory tract illness in infants from birth up to six months of age 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; injection site pain was the most frequent mild adverse event. In September 2021, Pfizer 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 RSVpreF in adults ages 60 years or older. Top-line data for this trial are expected in mid-2022.

Pfizer announced RSVpreF received Breakthrough Therapy Designation from the U.S. FDA on March 2, 2022, for the prevention of RSV-associated lower respiratory tract disease in infants from birth up to six months of age by active immunization of pregnant women, and RSVpreF received Breakthrough Therapy Designation from the U.S. FDA: for seniors on March 24, 2022. 

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. 

Pfizer RSVpreF RSV Vaccine Indication

RSVpreF is indicated to prevent RSV infections in infants and adults, says Pfizer. Globally, there are an estimated 33 million cases of RSV annually in children less than five 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 six 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.'

Pfizer RSVpreF RSV Vaccine While Pregnant

In a phase 2b clinical trial, we randomly assigned pregnant women at 24 through 36 weeks’ gestation to receive either 120 or 240 μg of RSVpreF vaccine (with or without aluminum hydroxide) or a placebo. Across the range of assessed gestational ages, infants of immunized women had similar titers in umbilical-cord blood and similar transplacental transfer ratios. STUDY CONCLUSIONS: RSVpreF vaccine-elicited neutralizing antibody responses with efficient transplacental transfer and without evident safety concerns.

A post-hoc efficacy analysis estimated a VE of 84.7% (95% CI 21.6-97.6) against medically attended RSV-associated lower respiratory tract illness and 91.5% (95% CI -5.6 to 99.8) against severe RSV-associated lower respiratory tract illness.

Pfizer RSVpreF RSV Vaccine Dosage

The phase 2b study evaluated one of 2 dose levels of the vaccine, 120 or 240 μg, formulated with or without aluminum hydroxide. A phase III trial of a 120 μg dose of RSVpreF without aluminum hydroxide is underway.

Pfizer RSVpreF RSV Vaccine News For 2018 - 2022

April 28, 2022 - Pfizer's RSV vaccine candidate RSVpreF vaccine-elicited neutralizing antibody responses with efficient transplacental transfer and without evident safety concerns in a phase 2b study.

March 24, 2022 - The U.S. FDA awarded the RSVpreF vaccine candidate its second Breakthrough Designation.

March 2, 2022 - Pfizer Inc. announced that its respiratory syncytial virus (RSV) vaccine candidate, PF-06482077 or RSVpreF, received Breakthrough Therapy Designation from the U.S. FDA for the prevention of RSV-associated lower respiratory tract illness in infants from birth up to six months of age by active immunization of pregnant women.

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 RSV bivalent prefusion F subunit investigational vaccine candidate (RSVpreF) in adults ages 60 years or older. "RSV is a significant cause of severe respiratory disease in older adults, and it can cause disability and death. Therefore, 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.

July 30, 2021 - Pfizer announced a challenge study, giving vaccines 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 the 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 outcomes from RSV occurs in the first months of life.

Pfizer RSVpreF 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 preventing moderate to severe lower respiratory tract illness (msLRTI-RSV) during the first RSV season.

In April 2020, positive top-line results were achieved for a Phase 2b proof-of-concept study of RSVpreF, which evaluated the safety, tolerability, and immunogenicity of RSVpreF in vaccinated pregnant women ages 18 through 49 and their infants. Pfizer will publish outcomes from this clinical trial at a future date.

In June 2020, Pfizer announced a multicenter, international Phase 3 clinical trial (NCT04424316) evaluating the efficacy, immunogenicity, and safety of RSVpreF when administered to pregnant women help protect their babies from the disease after they are born. This study remains ongoing.