Pfizer, BioNTech's COVID-19 vaccine shows 95% efficacy rate at final analysis

Pfizer and BioNTech announced Wednesday that their mRNA-based COVID-19 vaccine candidate BNT162b2 demonstrated an efficacy rate of 95% at the final efficacy analysis of a Phase III study. The companies noted the primary objective analysis is based on 170 cases of COVID-19, of which 162 cases were observed in the placebo group versus eight cases in the BNT162b2 arm.

Last week, Pfizer and BioNTech released interim results from the trial, showing that the vaccine was more than 90% effective in preventing COVID-19 in participants without evidence of prior SARS-CoV-2 infection. The first analysis was based on 94 cases of COVID-19, with the companies noting at the time that protection was achieved 28 days after the initiation of the vaccination, which consists of a two-dose schedule.

Vaccine effective in older adults

The latest results show that the efficacy rate, as measured seven days after the second dose, was the same whether the analysis looked only at people not previously infected with SARS-CoV-2, or if it included those with and without prior SARS-CoV-2 infection. Pfizer and BioNTech said that 10 severe cases of COVID-19 were observed in the trial, with nine of these occurring in the placebo group and one in the BNT162b2 arm. Results also showed that the efficacy in adults over 65 years of age was more than 94%, whilst it was consistent across age, gender, race and ethnicity demographics.

"We are grateful that the first global trial to reach the final efficacy analysis mark indicates that a high rate of protection against COVID-19 can be achieved very fast after the first 30-mcg dose, underscoring the power of BNT162 in providing early protection," remarked Ugur Sahin, chief executive of BioNTech.

Safety milestone hit

Pfizer and BioNTech also said that the safety milestone required by the FDA has been achieved, with an emergency-use application expected to be submitted "within days." Specifically, the companies noted that in a review of at least 8000 participants in the study, the only Grade 3 adverse events that had a frequency of 2% or more after the first or second dose was fatigue at 3.8% and headache at 2% following dose two.

According to Pfizer, the FDA is expected to discuss the application at an advisory committee meeting in December. Sahin said "if all goes well, I could imagine that we gain approval in the second half of December and start deliveries before Christmas, but really only if all goes positively." The data will be filed with other regulatory agencies around the world as well, whilst also being submitted for publication in a peer-reviewed medical journal once analysis of the study is completed. Pfizer and BioNTech indicated that the study, which began on July 27, has enrolled 43,661 participants to date, with 41,135 of these receiving a second dose of the vaccine candidate as of November 13. The trial is designed to collect efficacy and safety data for an additional two years.   

The announcement from Pfizer and BioNTech comes a matter of days after Moderna reported that its experimental COVID-19 vaccine mRNA-1273 showed an efficacy rate of 94.5% in the first interim analysis of a Phase III study. Moderna noted that the analysis was based on 95 cases of coronavirus infection, of which 90 cases were observed in the placebo group versus five in the mRNA-1273 group. For related analysis, see ViewPoints: Two is a vital trend towards normalcy with COVID-19 vaccines, and Physician Views results: Lack of durability, emergence of serious side effects top doctors' concerns about COVID-19 vaccines.

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