Pfizer, BioNTech Combination Flu and COVID-19 Shot Misses 1 of 2 Endpoints

Shares of Pfizer (PFE) and American depositary receipts (ADRs) of BioNTech (BNTX) dropped in intraday trading Friday following disappointing results from a late-stage study of the drugmakers’ combined COVID-19 and flu vaccine in adults.

The companies reported that just one of two endpoints was reached in a Phase 3 trial of the experimental treatment which used the Pfizer-BioNTech COVID-19 drug and Pfizer’s flu medicine. While positive responses to COVID-19 and influenza A viruses were seen, they were not for influenza B. 

Pfizer, BioNTech ‘Evaluating Adjustments’

The companies said they are “evaluating adjustments to the candidate” and will discuss the results with health officials.

BioNTech Chief Executive Officer (CEO) Dr. Ugur Sahin explained that both firms are “dedicated to developing combination vaccines which provide broader protection against multiple respiratory diseases,” and that the insights gained from this trial “are highly valuable and will play a crucial role in guiding the further development.”

Included in the announcement was an update on a Phase 2 study of Pfizer’s experimental second-generation trivalent influenza mRNA vaccine, which the drug maker said “showed encouraging data demonstrating robust immunogenicity against all strains compared to a standard of care influenza vaccine.”

Pfizer shares, which began the day roughly flat for the year, and BioNTech ADRs slipped 1.9% and 2.9%, respectively, as of 1:30 p.m. ET Friday. BioNTech ADRs are down about 20% in 2024.