New York: Pfizer shared an update on the Phase 2 trial (NCT06436703) to evaluate second-generation candidates against influenza was initiated earlier this year and enrolled 450 participants 18-64 years of age, who were randomised to receive investigational mRNA-based influenza vaccines or influenza vaccines approved by the US Food and Drug Administration (FDA).
As previously stated, Pfizer announced positive top-line Phase 3 results from its first-generation quadrivalent (qIRV) vaccine candidate which achieved the first and only demonstration of efficacy for an mRNA vaccine in a group of study participants 18-64 years of age.
The primary endpoints for the qIRV first-generation candidate were not met in adults aged 65 and older, as statistical non-inferior relative vaccine efficacy (rVE) compared to a licensed influenza vaccine was not met based on the number of cases accrued. The company developed second-generation candidates with the goal of improving immunogenicity and potentially breadth of protection, including new tIRV formulations that matched updated recommendations by the World Health Organisation (WHO) and the FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC).
The tIRV formulations elicited robust influenza A responses and B responses, including continued trend of higher influenza A responses versus a licensed influenza vaccine. There were no safety signals reported. Data from this Phase 2 trial for adults 65 years of age and older will become available at a later date. Pfizer will also continue to evaluate its influenza vaccine program and discuss next steps with health authorities.
