Pfizer and BioNTech have received fast track designation from the US Food and Drug Administration (FDA) for two of their four potential Covid-19 vaccines.

The two potential vaccines, BNT162b1 and BNT162b2, are part of the companies’ BNT162 mRNA-based vaccine programme. The candidates are currently in ongoing Phase I / II clinical trials in the US and Germany.

FDA granted the fast track designation after reviewing preliminary results from Phase I / II studies and also data from animal immunogenicity studies.

Earlier this month, Pfizer and BioNTech reported positive preliminary results from the ongoing Phase I / II trial of BNT162b1 in the US.

The results were from 24 participants who were given two 10µg and 30µg injections, 12 subjects who had a single 100µg injection and nine subjects who received two doses of placebo.

According to the findings, the vaccine candidate could be given at a dose that was well tolerated and produced dose-dependent immunogenicity.

Early results from BNT162b1’s German trial are expected to be available this month.

Pfizer Global Regulatory Affairs senior vice-president Peter Honig said: “The FDA’s decision to grant these two Covid-19 vaccine candidates fast track designation signifies an important milestone in the efforts to develop a safe and effective vaccine against SARS-CoV-2.

“We look forward to continuing working closely with the FDA throughout the clinical development of this programme, Project Lightspeed, to evaluate the safety and efficacy of these vaccine candidates.”

The BNT162 programme involves at least four vaccine candidates, made up of a different mRNA format and target antigen combination.

BNT162b1 and BNT162b2 contain nucleoside modified RNAs and are formulated in lipid nanoparticles. BNT162b1 encodes a SARS-CoV-2 receptor-binding domain (RBD) antigen, while BNT162b2 encodes the virus’ full-length spike protein antigen.

If positive data is obtained in ongoing clinical studies and the vaccine candidate gets regulatory approval, the partners estimate to produce up to 100 million doses by the end of this year and more than 1.2 billion doses by the end of next year.