COVID-19: Pfizer-BioNTech test third dose of vaccine against new variants of SARS-CoV-2. The study is part of the clinical development.
Pamela Cruz. Peninsula 360 Press [P360P].
Pfizer and BioNTech announced Thursday that they have initiated an evaluation of the safety and ability of their antigen to activate the immune system and induce an immune response - immunogenicity - with a third dose of their COVID-19 vaccine, following strong concerns about variants of the SARS-CoV-2 virus.
In a statement, Pfizer said that these tests "will serve to understand the effect of a boost in immunity against COVID-19 caused by circulating and potential emerging variants".
The study will be based on U.S. Phase 1 study participants who will be offered the opportunity to receive 30 micrograms as a booster of the current vaccine 6 to 12 months after receiving their initial two-dose regimen.
The study is part of the companies' clinical development strategy to determine the efficacy of a third dose against evolving variants.
Separately, in order to be prepared for any potential future strain changes, Pfizer and BioNTech are in discussions with regulatory authorities, including the U.S. Food and Drug Administration (FDA) and the European Medicines Agency, regarding a clinical study to allow registration to evaluate a variant-specific vaccine that has a modified mRNA sequence.
This study would use a new Pfizer-BioNTech vaccine construct based on the B.1.351 lineage, first identified in South Africa.
With such studies, the company could quickly update the current vaccine if the need arises to protect against COVID-19 from circulating strains.
Thus, in accordance with the updated guidance issued by the FDA regarding the emergency use of vaccines to prevent COVID-19, which provides recommendations for evaluating a modified vaccine to address variants, the companies expect to pursue validation of future modified mRNA vaccines with a regulatory pathway similar to that which currently exists for influenza vaccines.
"While we have not seen any evidence that circulating variants result in a loss of the protection provided by our vaccine, we are taking multiple steps to act decisively and be ready should a strain become resistant to the protection provided by the vaccine. This booster study is critical to understanding the safety of a third dose and immunity against circulating strains," said Albert Bourla, president and CEO of Pfizer.
The executive added that, at the same time, it is making the appropriate investments and engaging in the necessary discussions with regulators to help it position, develop and seek licensure for an updated mRNA vaccine or a booster if needed.
"Our proactive clinical development strategy aims to create the foundation today, which will enable us to address tomorrow's challenges. We want to be prepared for different scenarios," said Ugur Sahin, CEO and co-founder of BioNTech.
"Therefore, we will evaluate a second booster in the current regimen and prepare for a possible rapid adaptation of the vaccine to address new variants that might escape the current version of our mRNA-based vaccine," he stressed.
In that regard, he noted that the flexibility of their proprietary mRNA vaccine platform allows them to technically develop booster vaccines within weeks, if needed.
This study will evaluate up to 144 Phase 1 participants in two age cohorts, 18 to 55 and 65 to 85 years. The study will include trial participants who received the two doses in the Phase 1 study 6 to 12 months ago to assess the boosting ability of BNT162b2.
Therefore, the study will evaluate the safety and tolerability of a third vaccine regardless of the trial participant's level of antibody titers. Participants will be evaluated at the time they receive the third dose, then one week and one month later, and Pfizer and BioNTech plan to study the ability of those participants' sera to neutralize the SARS-CoV-2 strains of interest.
Pfizer-BioNTech COVID-19 vaccine has not been approved or licensed by the FDA, but has been cleared for emergency use by the FDA, under a license, to prevent COVID-19 disease for use in persons 16 years of age and older.
