The Phase IIb/III trial is expected to begin in late July 2020 and could contain 30,000 healthy participants. In addition to the participants who received two doses, another group received a single dose of 100 µg. "Virus neutralizing antibody titers achieved after two doses are greater than convalescent antibody titers", tweeted Peter Hotez, a vaccine scientist from Baylor College of Medicine in the United States, who was unrelated to the study.
They said the program is evaluating at least four experimental vaccines, each of which represents a unique combination of mRNA format and target component of the novel coronavirus, SARS-CoV-2.
"Overall, the preliminary data demonstrated that BNT162b1 could be administered in a dose that was well tolerated and generated dose dependent immunogenicity, as measured by RBD-binding IgG concentrations and SARS-CoV-2 neutralizing antibody titers", said Pfizer.
BioNTech's co-founder and Chief Executive Officer Ugur Sahin stated, "These first trial results show that the vaccine yields immune activity and causes a strong immune response", adding that larger trials will be conducted to see if this development can be translated into protection against a real infection.
The data on the vaccine was disclosed Wednesday in a paper released on MedRXiv; however, it is yet to be peer-reviewed.
An ongoing collaborative Phase1/2 clinical trial in the U.S. and involving 45 participants aged between 18 and 55 have received either 10, 30, or 100 microgram doses of the drug BNT162b1 vaccine or a placebo over 21 days.
This early-stage study of BNT162b1 included 45 healthy adults between the ages of 18 and 55, with participants split into three dose groups.
In the phase 1/2 trial, all 24 patients that received the two lower doses (10 micrograms and 30 micrograms) showed elevated antibody levels, and those responses, on average, were above the levels observed in the comparison panel of 38 patients that had naturally contracted SARS-CoV-2. Subjects reported mild side effects, including pain at the injection site and low-grade fever, which are common vaccine reactions.