Pfizer has begun dosing the first participants in a pivotal phase 3 clinical trial to evaluate its quadrivalent modified RNA (modRNA) influenza candidate in approximately 25,000 healthy US adults, the company announced.
Each year, even when currently available vaccine strains match circulating influenza virus strains well, those vaccines typically offer only 40% to 60% protection, with even lower protection in years with poor matching of strains, Pfizer noted in a statement.
Influenza causes 12,000 to 52,000 deaths in the US every year, but the strains used in vaccines have to be changed continually ahead of the flu season as circulating viruses keep evolving.
The company hopes that its influenza candidate could potentially allow better strain matches in future years, and in a pandemic influenza situation, due to the flexibility of mRNA technology and mRNA-based influenza vaccines would require only the genetic sequence of the virus.
“For years, there has been a need to better address the burden of influenza, despite the use of existing seasonal flu vaccines. Our experience with RNA viruses and mRNA technology has given us an even deeper understanding of the opportunity to potentially provide more efficacious vaccines that could further reduce the yearly rates of the severe outcomes of viral disease like flu, including hospitalisation and death,” said Annaliesa Anderson, senior vice president and chief scientific officer, vaccine research and development, Pfizer.
The quadrivalent modRNA vaccine candidate will encode World Health Organization (WHO) recommended strains for the Northern Hemisphere 2022-23 cell culture or recombinant-based influenza vaccines.
The phase 3 study is informed by previously shared data from the ongoing phase 2 trial, demonstrating a safety and immunogenicity profile supportive of programme advancement and is part of Pfizer’s broader influenza vaccine programme, focused on leveraging mRNA technology in a vaccine to help protect against the flu.
“We are excited to start the first phase 3 efficacy study of an mRNA-based influenza vaccine that could potentially deliver an improved flu vaccine to help address the significant burden of this disease,” Anderson added.
In 2018, Pfizer entered into a worldwide collaboration and licence agreement with BioNTech under which Pfizer has the exclusive right to carry out the clinical development and commercialisation of mRNA‐based influenza vaccines.