FDA briefing materials point to immune bridging studies for pediatric COVID-19 vaccines
COVID-19 vaccine manufacturers may be able to rely on neutralizing antibody titers as a surrogate for efficacy in pediatric patients.
Briefing documents published ahead of Thursday’s Vaccines and Related Biological Products Advisory Committee meeting noted that the milder disease course observed in children infected with SARS-CoV-2 would likely make it infeasible to adequately power a study designed to measure clinical outcomes.
Instead, FDA suggested sponsors could design immunobridging studies in which efficacy in pediatric populations could be inferred based on an immune response that is non-inferior to that observed in the adult population.
The agency said that because no specific neutralizing antibody titer has been established as predictive of protection, companies should use two non-inferiority metrics to establish efficacy: a 10% non-inferiority threshold on seroresponse rates; and a 1.5-fold non-inferiority margin for geometric mean titers.
At Thursday’s meeting, the panel will be asked to discuss the safety data, including database size and duration of follow-up, that would support an emergency use authorization (EUA) or licensure assuming there’s sufficient evidence to support the efficacy of COVID-19 vaccines in pediatric populations.
FDA authorized Comirnaty from Pfizer Inc. (NYSE:PFE) and BioNTech SE (NASDAQ:BNTX) last month in children ages 12-15; Moderna Inc. (NASDAQ:MRNA) plans to submit data from the Phase II/III TeenCOVE study of its COVID-19 vaccine to regulators this month to support an EUA in adolescents.