Novavax reports positive results for respiratory syncytial virus vaccine candidate

ROCKVILLE, Md. — Novavax Inc. announced Jan. 12 that it has completed a pre-clinical safety and efficacy study of its RSV vaccine candidate in cotton rats.

Results from this study are needed to support an Investigational New Drug (IND) application to advance this novel recombinant F protein particle based RSV (RSV-F) vaccine candidate into clinical development.

This vaccine candidate is composed of recombinant 'F' or 'fusion' protein of RSV that is used by the virus to infect and fuse with cells in the respiratory tract and cause disease.

In the current study, Novavax tested its RSV-F vaccine candidate in cotton rats, a well-accepted animal model for RSV infection and disease.  

RSV vaccines require a heightened evaluation of safety because of a failed study in children in the mid-1960s with a formalin-inactivated RSV vaccine candidate that caused enhancement of the disease. In the current study, the lungs of RSV challenged cotton rats were examined and there was no sign that immunization with the Novavax RSV-F vaccine candidate resulted in enhanced disease. However, RSV-induced pathology in the lungs was observed in animals immunized with a formalin-inactivated RSV control.

"We are excited to report steady progress towards the development of a vaccine against RSV, an important virus that is the leading cause of viral death in infants," said Dr. Rahul Singhvi, president and CEO of Novavax. "A safe and effective vaccine against RSV is especially needed in very young children since RSV infection does not provoke lasting immunity. An effective vaccine would also be important in adults, especially the elderly, where RSV illness is common. There is currently no approved vaccine for the prevention of RSV."

RSV is the most commonly identified cause of lower respiratory tract illnesses in infants and young children. Repeated infections occur throughout life causing moderate to severe cold-like symptoms. More severe lower respiratory tract disease is also seen in elderly adults over age 65 years, similar to the severe illness witnessed in children. It is estimated that RSV infects more than 8.5 million adults annually, including people older than 65.

This virus is responsible for approximately 900,000 hospitalizations annually in the United States and major European countries. In the United States alone, RSV leads to 177,500 hospitalizations in high-risk adults resulting in annual medicals costs exceeding $1 billion.