Pfizer already got a major boost for its maternal RSV vaccine this week, when trials for GlaxoSmithKline’s rival shot were halted. And now the FDA has granted Pfizer a breakthrough therapy tag, which could allow the New York pharma to put the pedal to the metal and leave its U.K. peer in the dust.
The tag has been granted to Pfizer’s PF-06482077, or RSVpreF, to prevent lower respiratory tract illness in infants from birth to up to six months via immunization of pregnant women. Pfizer said the decision was based on a phase 2b trial assessing the safety and immunogenicity of the shot when administered to women 18 through 49 years old at 28 and 36 weeks gestation. The results of that trial, which achieved “positive topline results” in April 2020, will be released at a later date, Pfizer said.
A breakthrough therapy tag grants drugmakers an expedited development and review process for treatments that address serious or life-threatening conditions. The company will receive extra FDA guidance and eligibility for rolling and priority review.
The RSV virus causes an average of 58,000 hospitalizations a year in the U.S., with 100-500 deaths among children younger than five years old as well as 177,000 hospitalizations with 14,000 deaths among adults aged 65 years or older, according to the CDC.
Pfizer is one of many Big Pharmas working on a preventative shot for RSV, a vaccine that has long stymied drugmakers. But now the industry seems to be on the cusp of bringing one to market. The companies involved—Sanofi, AstraZeneca, Johnson & Johnson, GSK, Moderna, etc.—are working on various patient populations with multiple candidates. Pfizer and GSK are the most advanced on the maternal vaccine front; however, the U.K. pharma met with a major setback last week when its trials were placed on hold.
GSK had hoped to swiftly resolve the issues that led to the temporary pause on Feb. 18 of a phase 3 trial for the maternal population, but on Monday, the pause became a stop. The issues stem from a safety signal that cropped up, although few details on the nature of the concern have been issued
The advantage then shifted to Pfizer, and the FDA tag is another boost for the New York pharma’s program. RSVpreF is now in a phase 3 trial in pregnant women to protect their babies after they are born. The study is expected to read out in the second half of this year. The shot is also being tested in a late-stage study of adults 60 years and older, and that trial got underway in September 2021, with topline data expected this half.