PfizerPfizer Inc. (NYSE: PFE) announced that the U.S. Food and Drug Administration’s (FDA) Vaccines and Related Biological Products Advisory Committee (VRBPAC) voted that the available data support the efficacy and safety of its unadjuvanted bivalent respiratory syncytial virus (RSV) prefusion F vaccine candidate RSVpreF or PF-06928316. The Committee voted 14 to 0 on effectiveness and 10 to 4 on safety. The vaccine candidate is currently under FDA review for the prevention of medically attended lower respiratory tract disease (MA-LRTD) and severe MA-LRTD caused by RSV in infants from birth up to six months of age by active immunization of pregnant individuals.

"We are encouraged by the outcome of today's VRBPAC meeting as it is a critical step forward in the scientific community's long-sought-after goal to help prevent RSV disease in infants during their most vulnerable first six months of life," said Annaliesa Anderson, Ph.D., Senior Vice President and Chief Scientific Officer, Vaccine Research and Development, Pfizer. "If approved, our RSV vaccine candidate has the potential to be the first maternal immunization vaccine to help protect infants at first breath through their first six months of life from this potentially serious infection."

The VRBPAC based its recommendation on the scientific evidence shared by Pfizer, including primary analysis results from the pivotal Phase 3 clinical trial (NCT04424316) MATISSE (MATernal Immunization Study for Safety and Efficacy) announced in November 2022. These results were also recently published in The New England Journal of Medicine.

The role of the VRBPAC is to provide recommendations to the FDA; however, these recommendations are not binding. The FDA's decision on the potential approval of RSVpreF for the prevention of MA-LRTD and severe MA-LRTD caused by RSV in infants by active immunization of pregnant individuals is expected by the Prescription Drug User Fee Act (PDUFA) goal date in August 2023.

Burden of RSV in Infants

RSV is a contagious virus and a common cause of respiratory illness.(1) The virus can affect the lungs and breathing passages of an infected individual and can potentially cause severe illness in young infants, older adults, and individuals with certain chronic medical conditions.(2,3,4)

In the United States, approximately 500,000 to 600,000 cases of MA-LRTD due to RSV occur annually in infants less than 12 months of age.(5) Worldwide, there are an estimated 6.6 million cases of RSV annually in infants less than six months of age, with approximately 45,000 dying each year from complications associated with the infection, and the vast majority in developing countries.(6,7,8)

About RSVpreF

Pfizer is currently the only company pursuing regulatory applications for an RSV investigational vaccine candidate for both an older adult indication, as well as a maternal indication to help protect infants through maternal immunization.

In December 2022, Pfizer announced that the FDA had granted priority review to a biologics license application for RSVpreF for the prevention of RSV disease in older adults with a decision on whether or not to approve RSVpreF expected by thePDUFA goal date later this month. This was followed by the February 2023 vote by VRBPAC in support of the safety and effectiveness of RSVpreF in adults 60 years of age and older. The FDA’s VRBPAC based its recommendation on the scientific evidence shared by Pfizer, including interim data from the pivotal Phase 3 clinical trial (NCT05035212) RENOIR (RSV vaccine Efficacy study iN Older adults Immunized against RSV disease). Top-line results for RENOIR were previously announced by Pfizer in August 2022 and presented at IDWeek and the CDC's Advisory Committee on Immunization Practices (ACIP) in October 2022, as well as recently published in The New England Journal of Medicine.

In February 2023, it was announced that the European Medicines Agency (EMA) accepted for review Pfizer’s Marketing Authorization Application (MAA) under accelerated assessmentfor RSVpreF, as submitted for both older adults and maternal immunization to help protect infants against RSV. The formal review process by the EMA’s Committee for Medicinal Products for Human Use (CHMP) currently is ongoing. Also in February 2023, Pfizer Japan announced an application was filed with the Ministry of Health, Labor and Welfare for RSVPreF as a maternal immunization to help protect infants against RSV. In April 2023, Pfizer Canada announced Health Canada accepted RSVpreF for review for both individuals ages 60 and older and as a maternal immunization to help protect infants against RSV.

Earlier this month, Pfizer also announced it would be initiating multiple clinical trials evaluating RSVpreF in healthy children ages 2-5; children ages 5-18 with underlying medical conditions; adults ages 18-60 at high-risk due to underlying medical conditions; and adults ages 18 and older who are immunocompromised and at high-risk for RSV.(9)

Pfizer's investigational RSV vaccine candidate builds on foundational basic science discoveries including those made at the National Institutes of Health (NIH), which detailed the crystal structure of prefusion F, a key form of the viral fusion protein (F) that RSV uses to enter human cells. The NIH research showed that antibodies specific to the prefusion form were highly effective at blocking virus infection, suggesting a prefusion F-based vaccine may confer optimal protection against RSV. After this important discovery, Pfizer tested numerous versions of a stabilized prefusion F protein and identified a candidate that elicited a strong anti-viral immune response in pre-clinical evaluations. The bivalent vaccine candidate is composed of equal amounts of recombinant RSV prefusion F from subgroups A and B.

About Pfizer: Breakthroughs That Change Patients' Lives

At Pfizer, we apply science and our global resources to bring therapies to people that extend and significantly improve their lives. We strive to set the standard for quality, safety and value in the discovery, development and manufacture of health care products, including innovative medicines and vaccines. Every day, Pfizer colleagues work across developed and emerging markets to advance wellness, prevention, treatments and cures that challenge the most feared diseases of our time. Consistent with our responsibility as one of the world's premier innovative biopharmaceutical companies, we collaborate with health care providers, governments and local communities to support and expand access to reliable, affordable health care around the world. For more than 170 years, we have worked to make a difference for all who rely on us.

1. Centers for Disease Control and Prevention. Respiratory Syncytial Virus Infection (RSV). https://www.cdc.gov/rsv/index.html. Updated December 18, 2020. Accessed November 18, 2022.
2 .Centers for Disease Control and Prevention. RSV Transmission. https://www.cdc.gov/rsv/about/transmission.html. Updated December 18, 2020. Accessed November 18, 2022.
3. Centers for Disease Control and Prevention. Respiratory Syncytial Virus Infection (RSV) - Older Adults are at High Risk for Severe RSV Infection Fact Sheet. https://www.cdc.gov/rsv/factsheet-older-adults.pdf. Accessed November 18, 2022.
4. Centers for Disease Control and Prevention. RSV in Infants and Young Children. https://www.cdc.gov/rsv/high-risk/infants-young-children.html. Updated December 18, 2020. Accessed November 18, 2022.
5. Rainisch G, Adhikari B, Meltzer MI, Langley G. Estimating the impact of multiple immunization products on medically-attended respiratory syncytial virus (RSV) infections in infants. Vaccine. 2020;38(2):251-257. doi:10.1016/j.vaccine.2019.10.023
6. Rha B, Curns AT, Lively JY, et al. Respiratory Syncytial Virus-Associated Hospitalizations Among Young Children: 2015-2016. Pediatrics. 2020;146(1):e20193611. doi:10.1542/peds.2019-3611
7. Li et al. Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in children younger than 5 years in 2019: a systematic analysis. Lancet 2022; 399: 2047-64.
8. Scheltema NM, Gentile A, Lucion F, et al. Global respiratory syncytial virus-associated mortality in young children (RSV GOLD): a retrospective case series [published correction appears in Lancet Glob Health. 2017 Dec;5(12 ):e1190]. Lancet Glob Health. 2017;5(10):e984-e991. doi:10.1016/S2214-109X(17)30344-3.
9. Pfizer First Quarter 2023 Earnings Teleconference Presentation, May 2, 2023, page 22, https://s28.q4cdn.com/781576035/files/doc_financials/2023/q1/Q1-2023-Earnings-Charts-FINAL.pdf