FDA Group – The New York Times

A Food and Drug Administration advisory panel voted Thursday to approve a Pfizer vaccine to prevent a severe respiratory virus that poses a potentially deadly threat to infants.

This vaccine will be the first to protect babies against respiratory syncytial virus, or RSV, which is the reason so many babies end up in children’s hospitals every year and kill several hundred children under the age of 5 every year.

The agency’s fourteen advisors unanimously agreed that the vaccine is effective, and the FDA generally follows the recommendations of its advisory panels.

Ten out of 14 agreed that the vaccine is safe, voicing some concerns about increased rates – not all statistically significant – of preterm birth among mothers who received the vaccine compared to those who received a placebo.

The vote follows a previous FDA decision. approve the first RSV vaccine for the elderly in the United States. Several other options are still being evaluated.

Pfizer’s pregnancy vaccine, called Abrysvo, is being considered ahead of another option presented by the FDA for infants, a monoclonal antibody injection intended to provide protection for five months.

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 die. (Up to 160,000 adults aged 65 and over are hospitalized with the virus each year, and about 10,000 die.)

The youngest children are most at risk. Data presented at the meeting showed that infants aged 6 months and younger are twice as likely to be hospitalized as infants or older children. Efforts to test the vaccine on infants began in the 1960s but were abandoned when the vaccine caused more severe cases, said Dr. Bill Gruber, Head of Clinical Research and Vaccine Development at Pfizer.

The prospect of immunizing large numbers of children in the fall, before the onset of winter, when RSV incidence is typically highest, would be “huge”. Jonathan Miller, pediatrician who sees children at Nemours Children’s Health Clinic and Hospital, Delaware Valley.

“I am excited about this prospect, as well as the prospects for other RSV vaccines under development,” the doctor said. Miller, who is not an advisor to the agency. “It looks like it will be the first thing that comes our way, and it will be a long time ago.”

The vaccine discussed on Thursday has been tested on about 7,300 women after the 24th week of pregnancy. About half received a placebo and half received the vaccine. During the first 90 days after birth, six infants in the vaccination group had serious cases of RSV compared to 33 infants in the placebo group, corresponding to an efficacy of nearly 82%.

Studying, published in the New England Journal of Medicine found that within six months of birth, the vaccine was 69 percent effective. In the treatment group, 19 children became seriously ill compared to 62 children in the placebo group.

The main safety concern at the time of the hearing was whether the vaccine was linked to preterm birth, a safety signal that caused GSK to stop trials of a similar RSV vaccine that was being tested on pregnant women. according to dr. Hal Barron, former CEO of the company. FDA approved this vaccine, called Arexvy, for seniors earlier this month. (Like GSK, Pfizer tested the same vaccine formula on older adults and infants.)

“We quickly stopped the test based on the fact that it confirmed that the signal was real,” the doctor said. Barron said in an investor presentation in March 2022, “but we’re still puzzled as to exactly why this happened.”

label for the GSK vaccine, it says that in tests of pregnant women, 6.8% of treated women had preterm births compared to 5% in the placebo group.

The Pfizer study reported preterm birth in 5.6% of pregnancies in the treatment group compared to 4.7% in the placebo group. FDA officials reported that the difference was not statistically significant.

Pfizer said that if the drug is approved, the company will conduct a post-marketing study of real-world use of the vaccine, monitoring medical records for preterm birth rates and other possible problems. However, agency consultants were skeptical about the plan to use data from medical bills to monitor vaccine safety. Some noted that such data may make it difficult to establish a link between the parent who received the vaccine and the child.

“I feel like we need to set a higher bar for validation,” said one of the consultants, Dr. Amanda Cohn, director of birth defects and infant diseases at the CDC, added that more data could help clarify questions about the impact on preterm birth.

Dr. Hana El Sahli, chair of the advisory committee and professor of virology at Baylor College of Medicine, said the number of preterm births among those who received the vaccine in the previous Pfizer study, in the main study in question, and in the GSK study of a similar product was of concern, especially given that that the United States is not at the epicenter of an RSV outbreak. She said the sample should have been examined more carefully.

“It was a big missed opportunity and I don’t think it’s fair that we’re kicking the can down the road to the general public,” the doctor said. El Sahli, who voted “No” to the question of whether the safety data is adequate.

There is another drug under regulatory review, an injectable monoclonal antibody developed by Sanofi and AstraZeneca called nirsevimab. It’s meant to be given in the hospital to babies born in winter or fall, Jonathan Heinrichs, Sanofi’s chief executive, said in an interview.

The drug is under FDA review and has been discovered in one study nearly 2,500 babies to reduce severe RSV by 75 percent.