Pfizer-BioNTech Covid/flu combo vaccine falters in Phase III

Pfizer and BioNTech recently disclosed that their Phase III trial for a combined mRNA vaccine targeting both influenza and Covid-19 did not meet one of its two primary objectives. While the investigational vaccine showed a higher tendency in neutralizing the influenza A strain compared to a licensed influenza vaccine, it did not achieve non-inferiority against the influenza B strain in terms of geometric mean titers (GMT) and seroconversion rates. Furthermore, the combination vaccine elicited comparable immune responses for SARS-CoV-2 when measured against Pfizer’s approved Covid-19 vaccine, Comirnaty (tozinameran).

The Phase III study, identified as NCT06178991, was organized as a randomized, parallel assignment trial and included over 8,000 adult participants aged between 18 and 64 years. Its primary focus was to assess the safety, tolerability, and immunogenicity of a single dose of the combination vaccine for dual protection against influenza and Covid-19. Importantly, no new safety concerns emerged during this phase of the study.

Commenting on the trial outcomes, Annaliesa Anderson, PhD, Senior Vice President and Head of Vaccine Research and Development at Pfizer, remarked, “Today’s results provide insight and direction towards achieving this goal, and we remain optimistic about our combination Covid-19 and influenza program, for which we are evaluating the next steps.”

Comirnaty, Pfizer’s Covid-19 vaccine, received full approval from the U.S. Food and Drug Administration (FDA) in August 2021 for individuals aged 12 and older. The vaccine reached its peak sales of $42.4 billion in 2022. However, recent trends have shown a decline in Covid-19-related revenue, leading pharmaceutical companies to search for ways to offset these financial losses.

In response to declining revenues, Pfizer initiated a cost reduction program in May that aimed to save approximately $1.5 billion by 2027. This followed an earlier announcement in October 2023 of a $3.5 billion cost-saving program. The measures were prompted by a $5.5 billion non-cash charge after the U.S. government returned nearly eight million courses of Pfizer’s Covid-19 antiviral pill, Paxlovid (nirmatrelvir/ritonavir).

Despite these challenges, mRNA Covid-19 vaccines continue to be a topic of interest. The FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) recently voted unanimously to update existing Covid-19 vaccines, including Comirnaty, to target the JN.1 variant. In addition to Pfizer’s Comirnaty, the FDA has also granted full approval to Moderna’s SpikeVax (elasomeran).

In summary, while the combination mRNA vaccine trial from Pfizer and BioNTech showed promise in some areas, it ultimately did not meet all primary endpoints. The companies are now contemplating the next steps for their combined influenza and Covid-19 vaccine program. As the landscape of mRNA vaccine technology continues to evolve, updates and further developments are expected, particularly in light of regulatory decisions aimed at addressing emerging Covid-19 variants.