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Pfizer Announces Start of Phase 3 Clinical Trial in Adults for Its Investigational Vaccine Against Respiratory Syncytial Virus (RSV)

Provided By: Pfizer


NEW YORK–(BUSINESS WIRE)– Pfizer Inc. today announced the initiation of a Phase 3 clinical trial evaluating the efficacy, immunogenicity, and safety of a single dose of its respiratory syncytial virus (RSV) 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. 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 & 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.”

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

RSV is a seasonal illness that commonly starts in the fall months, peaking in the winter when colds and other respiratory illnesses are more common.


Burden of RSV


Respiratory Syncytial Virus (RSV) is a common and pervasive cause of acute respiratory illness. The virus is highly contagious and affects the lungs and airways. Infections occur in people of all ages and can feel like the common cold for most young adults, but for infants, the immunocompromised, and older adults, it can be potentially life-threatening.

The risk of serious infection increases in older adults and for those with chronic heart or lung disease or a weakened immune system. In the U.S., it is estimated that more than 177,000 older adults over 65 years of age are hospitalized and 14,000 of them die each year due to RSV. There is no vaccine to prevent RSV and the medical community is limited to offering only supportive care for those with the illness.


About RSVpreF


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 structure of a key form of a viral protein that RSV uses to attack human cells. The NIH research showed that the antibodies that protect humans from RSV target this one form of the viral protein. Applying insights from this important work, Pfizer developed and tested numerous candidates and identified those that elicited a strong anti-viral immune response in pre-clinical evaluation, which led to the vaccine candidate that Pfizer is evaluating in human trials.

In July 2021, Pfizer provided an update on a Phase 2a study evaluating the safety, immunogenicity, and efficacy of RSVpreF in a virus challenge model in healthy adults 18 to 50 years of age. The results of the study enabled Pfizer to proceed to Phase 3. Detailed results from the Phase 2a study will be shared in a future scientific forum.


To learn more about joining an RSV clinical research trial with Tekton Research, click here!