Pfizer and BioNTech have reported positive, preliminary results from the ongoing Phase I/II clinical trial of mRNA-based Covid-19 vaccine candidate, BNT162b1, in the US.

Peer-reviewed data were published in the Nature journal.

BNT162b1 is a nucleoside-modified messenger RNA (modRNA) candidate designed to encode an optimised SARS-CoV-2 receptor binding domain (RBD) antigen.

Data found that the vaccine candidate’s administered dose was well tolerated and produced dose-dependent immunogenicity, determined using RBD-binding IgG concentrations and SARS-CoV-2 neutralising titers.

According to the published results, 30µg of the vaccine candidate, by seven days post  the second dose, triggered a SARS-CoV-2 neutralising geometric mean titer (GMT) that was 2.8 times the GMT of a SARS-CoV-2 convalescent human serum panel.

BioNTech added that new data showed continued increase in neutralising titers and, by 14 days following the second 30µg dose, the GMT was 4.6 times the convalescent serum panel GMT.

Pfizer senior vice-president and Vaccine Research & Development head Kathrin Jansen said: “The publication of peer-reviewed data from our mRNA-based vaccine development programme against SARS-CoV-2 in a world-renowned publication like Nature provides further validation of our rapid progress toward developing a safe and effective potential vaccine to help address this current pandemic.

“We are encouraged by the overall advancement of the programme and look forward to generating additional data from our ongoing studies.”

Peer-review process is ongoing for early data posted on medRxiv for BNT162b1 in the Phase I/II study in Germany.

Pfizer and BioNTech recently have advanced another Covid-19 vaccine candidate, BNT162b2, into a Phase II/III clinical trial. This is an event-driven trial that is set to enrol up to 30,000 subjects aged 18 to 85 years.

The companies continue to capture data from the Phase I/II trials and expect to submit findings on BNT162b2 in the near future.