Pfizer to seek FDA approval for maternal RSV vaccine
The vaccine demonstrated efficacy of almost 82% against severe RSV in infants from birth through the first 90 days of life.
Photo: FG Trade/Getty Images
Drugmaker Pfizer, emboldened by positive results from an immunization trial for its bivalent respiratory syncytial virus (RSV) vaccine candidate, will be seeking FDA approval for the vaccine this year, the company said this week.
Pfizer will be ending enrollment in the study and will seek approval before the end of the calendar year.
RSV is a respiratory virus, and while its cold-like symptoms are typically mild, it can in some instances cause a deeper illness in children and older adults specifically. The vaccine, which is intended for pregnant women, is designed to pass immunity onto the child, who retains it after the child's birth.
In the clinical trial, the vaccine demonstrated efficacy of almost 82% against severe RSV in infants from birth through the first 90 days of life. After that, the vaccine showed a still-high efficacy of 69.4% through the first six months of life.
If approved, Pfizer's RSV vaccine candidate could be the first maternal vaccine available to help prevent RSV in young infants. Pfizer is currently the only company with an investigational vaccine for RSV in both infants and older adults.
WHAT'S THE IMPACT?
Analysis of the clinical trial was conducted by the external and independent Data Monitoring Committee, which found no safety concerns either for vaccinated adults or their newborns.
According to Pfizer, RSV can affect the lungs and breathing passages of an infected person and can be potentially life-threatening for young infants, people with certain chronic medical conditions and older adults. In the U.S. alone, about 2.1 million outpatient visits and 58,000 hospitalizations due to RSV occur each year among children younger than 5 years old.
Worldwide, RSV results in the death of approximately 102,000 children annually. Half of these deaths occur in infants less than 6 months old, and the vast majority happen in developing countries.
RSV bronchiolitis is the leading cause of infant hospitalization due to viral respiratory illness, which is characterized by respiratory distress that can result in death. There is no specific treatment for RSV, only supportive care measures like oxygen and fluids. Currently there is no vaccine to prevent RSV.
The investigational RSV vaccine candidate builds on foundational discoveries, including those made at the National Institutes of Health, which detailed the crystal structure of prefusion F, a key form of the viral fusion protein (F) that RSV uses to enter human cells. The NIH research showed that antibodies specific to the prefusion form were highly effective at blocking virus infection, suggesting a prefusion F-based vaccine may confer optimal protection against RSV.
After this discovery, Pfizer tested numerous versions of a stabilized prefusion F protein and identified a candidate that elicited a strong antiviral immune response in pre-clinical evaluations.
Compared to a placebo, the RSV vaccine cut the need for infants to see a doctor by an average of more than 50% – less than Pfizer had initially hoped for, but still statistically significant.
THE LARGER TREND
The State of Maryland is responding to a surge of RSV infections in the state, with more than 500 RSV-related hospitalizations since the start of October, by setting aside $25 million in state funding to hire and recruit pediatric intensive care unit staff.
According to Governor Larry Hogan, RSV hospitalizations are increasing earlier and more rapidly than in previous years, with the 0-2 age group comprising 57% of hospitalizations. On October 14, the Maryland Department of Health announced $80 million in additional funding for healthcare providers across the state.
The directive comes as states are preparing for winter, which is expected to bring an increase in respiratory ailments, including RSV, COVID-19 and the flu.
Pfizer, meanwhile, entered into a definitive agreement in May to acquire Biohaven Pharmaceuticals, a maker of migraine treatments, for $11.6 billion. The proposed transaction includes Pfizer's acquisition of Biohaven's migraine drugs, including rimegepant, which is approved in the U.S. under the name NURTEC ODT. The same drug is approved in the European Union under the trade name VYDURA.
Twitter: @JELagasse
Email the writer: jeff.lagasse@himssmedia.com
