An advisory panel to the Food and Drug Administration on Thursday voted to approve a vaccine by Pfizer to prevent the severe acute respiratory virus, which is a deadly threat to infants.
The vaccine would be the first to protect children from respiratory syncytial virus, or RSV, which is why so many children are admitted to children’s hospitals each year and several hundred children under the age of five are killed each year.
Fourteen of the agency’s advisors unanimously agreed that the vaccine was effective, and the FDA usually follows the recommendations of its advisory committees.
Ten out of 14 agreed the vaccine was safe, with some concerns about higher rates of premature births among mothers who got the vaccine compared to those who got a placebo.
The vote comes on the heels of the FDA’s previous decision to Agree to the first RSV vaccine for the elderly in the United States. Many other options are still being evaluated.
Pfizer’s vaccine for pregnant women, called Abrysvo, is being reviewed before another option is submitted to the FDA that would be given to infants — a monoclonal antibody shot intended to provide five months of protection.
RSV is a common disease that is most severe in young children and the elderly. According to the Centers for Disease Control and Prevention, up to 80,000 children under the age of 5 are hospitalized with the virus each year and up to 300 children die. (Up to 160,000 adults 65 and older are hospitalized each year with the virus, and about 10,000 die.)
The youngest children face greater risks. Data presented at the meeting showed that infants 6 months of age or younger were twice as likely to be hospitalized as older infants or infants. Efforts to test a vaccine in infants began in the 1960s, but were halted when the vaccine caused more severe cases, said Dr. Bill Gruber, head of clinical vaccine research and development at Pfizer.
The prospect of vaccinating so many children in the fall, before winter when RSV rates are typically highest, would be “huge,” said Dr. Jonathan Miller, a pediatrician who sees children in clinic and hospital for Nemours Children’s Health. , Delaware Valley.
“I am excited about the possibility of this happening, and also about the possibility that there are other RSV vaccines in the pipeline,” said Dr. Miller, who is not an advisor to the agency. “This looks as if it will be the first to come our way, and it will be a long time coming.”
The vaccine under review was tested Thursday in about 7,300 women after the 24th week of pregnancy. About half of them received a placebo, and the other half were given the vaccine as a shot. During the first 90 days after birth, six babies in the vaccination group developed a serious case of respiratory syncytial virus, compared to 33 in the placebo group, resulting in an efficacy of about 82 percent.
the study, published In the New England Journal of Medicine, he showed that for six months after birth, the vaccine was 69% effective. In the treatment group, 19 children became seriously ill compared to 62 in the placebo group.
The main safety concern during the hearing was whether the vaccine was associated with premature birth, a safety signal that prompted GSK to halt its trial of a similar RSV vaccine being tested on pregnant patients. According to dr. Hal BarronFormer CEO of the company. Food and Drug Administration He approved this vaccine, called Arexvy, for seniors earlier this month. (Like GSK, Pfizer tested the same vaccine formulation on older adults and infants.)
“We quickly halted the trial based on her assertion that the signal was real, but we remain at a loss as to exactly why that happened,” Dr. Barron said in a March 2022 presentation to investors.
the attached GSK vaccine says that in tests of pregnant women, 6.8 percent of those who received the treatment had premature births, compared with 5 percent in the placebo group.
In the Pfizer study, premature birth was reported in 5.6 percent of pregnancies in the treatment group, compared to 4.7 percent in the placebo group. Officials at the US Food and Drug Administration (FDA) reported that the difference was not statistically significant.
If the drug is approved, Pfizer said, the company will conduct a post-approval study of the actual use of the vaccine, monitoring health records for the incidence of premature birth and other potential problems. Despite this, the agency’s advisors have expressed skepticism about a plan to use data generated from healthcare billing records to monitor vaccine safety. Many noted that such data could make it difficult to link the parent who received the vaccine to the child.
“I feel we should set higher standards for the review,” said one of the advisors, Dr. Amanda Cohn, director of the Division of Birth Defects and Infant Disorders at the Centers for Disease Control and Prevention, adding that more data may help clarify questions about the effects on premature birth.
The number of premature births among those who received the vaccine in a previous Pfizer study, in the main study under review and in GSK’s study of a similar product, said Dr. Hana Al-Sahli, chair of the advisory committee and professor of virology at Baylor College of Medicine, especially given the The United States is not in the midst of an RSV outbreak. She said the pattern should have been examined more carefully.
“This was a huge missed opportunity and I feel it’s unfair that we kicked the canister all the way to the larger public,” said Dr. Al-Sahli, who voted “no” to the question about whether the safety data was sufficient.
Another treatment under regulatory study is a monoclonal antibody developed by Sanofi and AstraZeneca, called nirsevimab. It’s meant to be given in the hospital to babies born during the winter or fall, said Jonathan Heinrich, a Sanofi executive, in an interview.
The drug is under review by the US Food and Drug Administration and has been found in one study nearly 2,500 infants to reduce severe RSV cases by 75 percent.