(CNN) — The COVID-19 vaccine candidate being developed by U.S. pharmaceutical company Pfizer and German biotechnology company BioNTech has yielded positive data in early tests, according to data released by the companies.
The companies announced these preliminary findings on Wednesday in a preprint document showing that participants in a Phase 1/2 study of the vaccine, called BNT162b1, responded to immunization and it was found to be well tolerated. The Phase 1/2 study is ongoing. The data has not yet been published in a peer-reviewed medical journal. Brazil will buy COVID-19 vaccines 0:43
"These clinical findings for the RNA-based vaccine candidate BNT162b1 are encouraging and strongly support accelerated clinical development and at-risk manufacturing to maximize the opportunity for rapid production of a SARS-CoV-2 vaccine to prevent COVID-19 disease," the researchers wrote in the preprint document, sponsored by BioNTech and designed by Pfizer.
For the initial study, 45 participants aged 18 to 55 were randomly assigned to receive a given dose of the vaccine or placebo. Twelve participants received two 10-microgram doses 21 days apart; 12 received two 30-microgram doses 21 days apart; 12 received a single 100-microgram dose on day one; and nine received placebo, according to the study.
In the seven days following vaccine injection, some participants who received a dose reported injection site pain, fever, or sleep disturbances, but "no serious adverse events were reported," according to the document.
Researchers found that the vaccine generated antibodies against the coronavirus in all participants 28 days after receiving a single 100-microgram injection or seven days after receiving a second 10- or 30-microgram dose.
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"These preliminary data are encouraging, as they demonstrate that BNT162b1, which exploits the SARS-CoV-2 RBD as a target antigen, is able to produce neutralizing antibody responses in humans at or above levels observed in convalescent sera, and that it does so at relatively low dose levels. We look forward to providing further data updates on BNT162b1," said Dr. Ugur Sahin, CEO and co-founder of BioNTech, in a company press release on Wednesday.
Pfizer and BioNTech announced on Wednesday that these preliminary data will help them determine a dose level for the vaccine and then select which of their multiple vaccine candidates will advance to a larger-scale global Phase 2/3 study, possibly starting as early as this month.
"We are encouraged by the clinical data from BNT162b1, one of four mRNA constructs we are clinically evaluating, and for which we have positive, preliminary, top-line findings," said Kathrin Jansen, Senior Vice President and Head of Vaccine Research and Development at Pfizer.
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"We are dedicated to developing potentially breakthrough vaccines and medicines, and in the face of this global health crisis, we approach this goal with the utmost urgency," said Jansen. "We look forward to publishing our clinical data in a peer-reviewed journal as quickly as possible."
According to the World Health Organization, there are 17 coronavirus vaccine candidates in clinical evaluation globally.
