FDA Panel Recommends RSV Vaccine to Protect Young Infants

A Food and Drug Administration advisory panel on Thursday voted in favor of approval of a Pfizer vaccine to prevent a serious respiratory virus that can pose a deadly threat to infants.

The vaccine will be the first to protect infants from respiratory syncytial virus (RSV), which causes millions of infants to be admitted to children’s hospitals each year and kills hundreds of children under the age of five each year.

Fourteen agency advisers unanimously agree that the vaccine works, and the FDA generally follows the advisory committee’s recommendations.

10 of 14 agreed that the vaccine was safe, but were concerned about increased preterm birth rates in vaccinated mothers compared to placebo-treated mothers (all not statistically significant) There were also voices expressing

The vote follows the FDA’s previous decision to approve the first RSV vaccine for the elderly in the United States. Some other options are still being evaluated.

Pfizer’s pregnant vaccine, called “Abrysvo,” is under review before being submitted to the FDA as another option for administration to infants. This is a monoclonal antibody vaccine that provides protection for 5 months.

RSV is a common disease, most severe in young children and the elderly. Up to 80,000 children under the age of five are hospitalized with the virus each year, and up to 300 die, according to the Centers for Disease Control and Prevention. (Each year, 160,000 adults over the age of 65 are hospitalized with the virus, and about 10,000 die.)

The youngest infants face the greatest risk. Data presented at the conference showed that infants under 6 months of age were twice as likely to be hospitalized compared to older infants and children. Efforts to test the vaccine in infants began in the 1960s, but were stopped after the vaccine caused more severe cases, said Bill Gruber, PhD, head of clinical vaccine research and development at Pfizer.

Jonathan Miller, M.D., a pediatrician who sees children at Nemours Children’s Medical Center, said the prospects for vaccinating many infants in the pre-winter fall, when RSV infection rates are usually highest, are “very high.” big,” he said. , Delaware Valley.

“I’m excited about this prospect and the prospect of other RSV vaccines in development,” said Dr. Miller, who is not an adviser to the agency. “This seems like the first one to come to us, but it’s going to take a long time.”

The vaccine under consideration was tested on Thursday in about 7,300 women after 24 weeks of pregnancy. About half received a placebo and half received the vaccine. During the first 90 days of life, 6 infants in the vaccinated group experienced severe cases of RSV compared to 33 in the placebo group, meaning an efficacy of nearly 82 percent.

the study, published A paper published in the New England Journal of Medicine showed that the vaccine was 69 percent effective during the first six months of life. Nineteen babies became seriously ill in the treatment group compared to 62 in the placebo group.

A key safety concern during the hearing was whether the vaccine was associated with preterm birth, which signaled safety and led GSK to launch a trial of a similar RSV vaccine it had been testing in pregnant patients. Canceled. According to Dr. Hal Baron, Former company officer. Earlier this month, the FDA approved the vaccine, called Arexvy, for the elderly. (Like GSK, Pfizer also tested the same vaccine regimen in the elderly and infants.)

“Based on the authenticity of the signal, we immediately halted the trial,” Barron said in a March 2022 investor presentation. “But I’m still baffled as to exactly why this happened.”

of label Regarding the GSK vaccine, a study of pregnant women reported that 6.8% of treated women had premature births, compared with 5% in the placebo group.

A Pfizer study reported preterm birth in 5.6 percent of pregnancies in the treatment group, compared with 4.7 percent in the placebo group. FDA officials reported that the difference was not statistically significant.

Pfizer said that if the drug is approved, it will conduct post-approval studies on actual vaccine use while monitoring health records for preterm birth rates and other possible problems. But the agency’s advisers have expressed skepticism about plans to use data generated from medical claims records to monitor vaccine safety. Some said such data could make it difficult to connect vaccinated parents to their children.

“We feel we need to set the bar higher,” said Amanda Cohn, Ph.D., director of the CDC’s Birth Defects and Infant Defects Division, one of the advisors, adding that more data will help the issue. He added that it might help clarify questions about Effects on preterm birth.

Dr. Hana El-Sari, Advisory Board Chair and Professor of Virology at Baylor College of Medicine, said that the number of preterm births among vaccinees in previous Pfizer studies, the main study under review, and the GSK study was: said. A similar product was a concern, especially considering the US isn’t in the middle of her RSV epidemic. He said patterns should have been considered more carefully.

Dr El-Sahari, who voted “no” when asked if the safety data were adequate, said, “This is a huge missed opportunity and it would be unfair to cut the way to reach a wider population.” I think,’ he said.

Another treatment being considered by regulators is a monoclonal antibody shot called Nilsevimab, developed by Sanofi and AstraZeneca. Sanofi executive Jonathan Heinrichs said in an interview that the drug is intended to be administered in hospital to babies born in the winter or fall.

This drug is under FDA review and has been found in a study Reduce severe RSV cases in about 2,500 infants by 75%.

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