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Pfizer announces the start of phase 3 clinical trials in adults for its investigational vaccine against Respiratory Syncytial Virus (RSV)

Pfizer has initiated RENOIR, a Phase 3 clinical trial of the Respiratory Syncytial Virus (RSV) bivalent prefusion F subunit investigational vaccine candidate in adults ages 60 or older. RSV is a contagious, seasonal illness, and a common and pervasive cause of severe acute respiratory illness in older adults with no vaccine currently available. The candidate addresses an unmet medical need, and represents the potential opportunity to protect both adults and infants against RSV.

Article Summary

RENOIR (RSV vaccine Efficacy study iNOlder adults Immunized against RSV disease), a Phase 3 clinical trial assessing the efficacy, immunogenicity, and safety of a single dose of Pfizer’s RSV bivalent prefusion F subunit investigational vaccine candidate (RSVpreF) in adults ages 60 years or older, has commenced.

The global, randomized, double-blind, placebo-controlled study will enroll an estimated 30,000 participants. It will evaluate safety and efficacy for the prevention of moderate to severe lower respiratory tract illness (msLRTI-RSV).

“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,” said Kathrin U. Jansen, Ph.D., Senior Vice President and Head of Vaccine Research and Development at Pfizer Inc. “The start of this Phase 3 study 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.”

Burden of RSV
RSV is a common, highly contagious illness, that commonly starts in the fall and peaks in the winter. It can feel like the common cold for most young adults but can be life-threatening for vulnerable groups, with an increased risk of serious infection in older adults, those with chronic heart or lung diseases, and the immunocompromised. Just in the U.S., an estimated 177,000 adults 65 years and older are hospitalized, 14,000 of whom die each year. Yet, there
is no vaccine to prevent RSV.

About RSVpreF
Pfizer’s investigational RSV vaccine candidate applies insights from the National Institute of Health’s (NIH’s) research, which details that the antibodies that protect humans from RSV target a key form of a viral protein with a crystal structure that the virus uses to attack human cells.

Results from a previous Phase 2a study, evaluating the safety, immunogenicity and efficacy of RSVpreF in healthy adults aged 18 to 50, enabled Pfizer to proceed to Phase 3. A previous Phase 2b proof-of-concept study assessing the safety, tolerability and immunogenicity of RSVpreF in vaccinated pregnant women aged 18 through 49 and their infants also demonstrated positive top-line results.

November 2018 saw RSVpreF receive Fast Track status from the FDA for the prevention of RSV-associated lower respiratory tract illness in infants through active immunization of
pregnant women.

About Pfizer: Breakthroughs That Change Patients’ Lives
Pfizer is one of the world’s premier innovative biopharmaceutical companies, collaborating with health care providers, governments, and local communities to support and expand access to reliable, affordable health care around the world. For more information, visit

(Source: Pfizer, 2nd September 2021)


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