A positive preliminary result from the phase 1/2 clinical trial determining the safety, tolerability, and immunogenicity of escalating doses of the BNT162b1 (COVID-19 vaccine candidate) was announced by Pfizer and BioNTech SE.

BNT162b1, an experimental modRNA (nucleoside-modified messenger RNA) vaccine, is responsible for encoding an optimized SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) spike glycoprotein RBD (receptor binding domain) antigen.

This randomized, placebo-controlled trial aimed to evaluate BNT162b1 for the management of COVID-19. The study recruited 45 healthy adults (aged 18 to 55 years) participants. Overall, two doses (21 days apart) of 10mcg or 30mcg of BNT162b1were given to 24 individuals. A total of 12 participants received A single injection of 100mcg of BNT162b1 were given to 12 participants and two doses of placebo were given to nine participants.

The preliminary data illustrated that 7 days after the second dose, patients who were administered 10mcg or 30mcg of BNT162b1 reported the highest neutralizing GMT (geometric mean antibody titers), corresponding to 1.8- and 2.8-times that observed from a panel of 38 convalescent human serology samples procured from patients having confirmed COVID-19 infection as shown in the following table:

Furthermore, at day 28, both doses of 10mcg and 30mcg led to an increase of RBD-binding IgG concentrations with GMCs (geometric mean concentrations) in comparison with the GMC in a panel of 38 sera from individuals who had contracted SARS-CoV-2 as depicted in the following table:

On day 28, a neutralizing GMT of 33 and an RBD-binding IgG GMC of 1778 units/mL were witnessed among individuals receiving a single dose of 100mcg BNT162b1. These results were illustrated to be 0.35-times and 3-times more that of the GMT and GMC of a panel of COVID-19 convalescent human sera, respectively.

The study data reveals that in humans, the vaccine candidate targeting the SARS-CoV-2 RBD antigen is capable of producing significant neutralizing antibody responses at or above the levels witnessed in convalescent sera. However, it is done at relatively lower dose levels.

For BNT162b1 10mcg or 30mcg, the most common adverse reactions noted were low-grade fever, local reactions, and systemic events which were dose-dependent, generally transient, and mild-moderate. A greater frequency of local reactions and systemic events were reported by patients receiving 100mcg of BNT162b1. No noxious side effects were noted.

Clinical evaluation of 1 of 4 mRNA constructs illustrated positive, preliminary, topline findings. In late July 2020, a Phase 2b/3 clinical study is anticipated to initiate after determination of an appropriate dose level and selection of the most viable vaccine candidate.

The manufacturing efforts of the companies are also improving to keep up with potential demand. By 2020, the companies are anticipating to produce up to 100 million doses and by 2021, possibly more than 1.2 billion doses, if approved.