Pfizer Inc.’s vaccine for respiratory syncytial virus received backing from a panel of US advisers for its safety and effectiveness in people 60 and older, a key endorsement that brings the drugmaker closer to the market for prevention of the lung infection.
Members of the panel that advises the Food and Drug Administration voted 7-4 with one abstention Tuesday that the data presented by the drugmaker show the effectiveness of the vaccine to prevent RSV. The same panel earlier endorsed the vaccine for safety by a 7-to-4 vote, again with one abstaining. The FDA doesn’t have to follow the recommendations of the Vaccines and Related Biological Products Advisory Committee, but it usually does.
Pfizer has been vying with the UK’s GSK Plc over which drugmaker will become the first to reach the US market with vaccines for the lung illness. GSK will face its own advisory committee hearing on Wednesday for what infectious disease specialists call the last big respiratory virus without a vaccine.
People with weak immune systems are particularly at risk along with older people, with 177,000 hospitalizations and 14,000 deaths recorded among US elderly each year from the disease, according to one 2005 study.
Both Pfizer and GSK have produced strong data showing the vaccines are effective in adults 60 and older, although there’s relatively little evidence on how much the vaccines reduce hospitalizations from RSV.
Several FDA advisory committee members raised safety questions because of two cases of Guillain-Barre syndrome among close to 20,000 trial participants who received the vaccine, which the FDA called an important potential risk before the hearing. GBS is a rare disorder in which the body’s immune system attacks the nerves, which could eventually lead to paralysis that is usually temporary. Rarely, vaccination can trigger the syndrome.
“One case is a red flag, two cases is very concerning, and it’s concerning to me that Pfizer doesn’t think that there are any safety concerns,” said panel member Marie Griffin, a Vanderbilt University health policy and medicine professor.
Confounding factors
Pfizer responded that there were confounding factors such as prior medical events that occurred in the same two patients and that the older population has higher incidences of the syndrome. The company said it would conduct a post-marketing study and is in touch with the FDA on designing it.
Other committee members said data were scant. Hana El Sahly, the committee chair, questioned why Pfizer didn’t wait until it had data for a second RSV season before applying for regulatory approval. Pfizer said that data is coming shortly. Some members even considered delaying the vote until more data became available, including any interactions with flu vaccines.
The RSV vaccine market for adults will be worth up to $10 billion by 2032. Pfizer is also facing off with collaborators Sanofi and AstraZeneca Plc to develop prevention for dangerous RSV infections in newborns, a market that could reach $1.5 billion, according to projections by Bloomberg Intelligence.
Once the FDA decides whether to go along with the advisory committee’s vote, the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices will issue recommendations that could have a big impact on how often the RSV vaccines are used—and how much revenue the two companies ultimately generate from them.
