Final efficacy data released today by Pfizer and BioNTech from their 44,000-patient Phase III trial of BNT162b2 show the COVID-19 vaccine candidate achieved the study’s first primary objective of 95% effectiveness in participants without prior SARS-CoV-2 infection.
Just 8 of 170 COVID-19 cases that arose during the trial were contracted by participants randomized to BNT162b2—the lead candidate of the companies’ BNT162 COVID-19 vaccine program—while the other 162 cases were seen in the group of patients randomized to placebo, Pfizer and BioNTech said.
That 95% efficacy rate is based on nearly twice as many COVID-19 cases as the 94 cases reported in early data released last week from the 43,538-participant Phase III trial (NCT04368728). That data, from the trial’s first interim efficacy analysis, showed the vaccine to be more than 90% effective in preventing COVID-19 in participants without evidence of prior SARS-CoV-2 infection.
The 95% slightly tops the 94.5% efficacy rate reported yesterday by Moderna for its leading mRNA-based COVID-19 candidate, mRNA-1273.
Pfizer and BioNTech added they will apply for emergency use authorization (EUA) for BNT162b2 “within days,” after achieving the milestone specified in FDA EUA guidance of a median of two months of safety data following the second and final dose of the vaccine candidate.
BNT162b2 is a nucleoside modified mRNA (modRNA) candidate that encodes an optimized SARS-CoV-2 full-length spike glycoprotein antigen. It has received the FDA’s Fast Track designation, as has the other advanced construct under study, BNT162b1, another nucleoside modRNA candidate which encodes an optimized SARS-CoV-2 receptor-binding domain (RBD) antigen.
Pfizer and BioNTech have studied BNT162b2, BNT162b1, and two other constructs of BNT162: a uridine containing mRNA (uRNA) candidate; and a candidate using self-amplifying mRNA (saRNA).
“The study results mark an important step in this historic eight-month journey to bring forward a vaccine capable of helping to end this devastating pandemic. We continue to move at the speed of science to compile all the data collected thus far and share with regulators around the world,” Pfizer Chairman and CEO Albert Bourla, DVM, PhD, said in a statement. “With hundreds of thousands of people around the globe infected every day, we urgently need to get a safe and effective vaccine to the world.”
The trial also met its second primary objective of achieving efficacy against COVID-19 in participants with and without prior SARS-CoV-2 infection. As with the first primary objective, patients were evaluated from 28 days after the first dose, 7 days after the second dose.
Ten severe cases of COVID-19 were seen in the trial—of which nine occurred in the placebo group and one in the BNT162b2 vaccinated group, the companies said.
The efficacy of BNT162b2 showed consistency across age, gender, race and ethnicity demographics, according to BioNTech and Pfizer. Of the trial’s 43,661 participants—up from 43,538 reported last week—approximately 42% of global participants and 30% of U.S. participants have racially and ethnically diverse backgrounds, the companies said.
In the U.S., 13.1% identified as Hispanic or LatinX; 10.1% as Black; 5.5% as Asian, and 1% as Native American. Globally, 26.1% was Hispanic/LatinX; 10%, Black; 4.5%, Asian; and 0.8%, Native American.
The observed efficacy in adults over 65 years of age was over 94%. The percentage of over-65 participants is not known because Pfizer and BioNtech only furnish the percentage of patients that are between ages 56–85—41% of global and 45% of U.S. participants. Consistent with earlier results, older adults tended to report fewer and milder solicited adverse events following vaccination, according to the companies.
BioNTech and Pfizer said the trial’s Data Monitoring Committee had not reported any serious safety concerns related to the vaccine. The companies cited a review of unblinded reactogenicity data from the final analysis, consisting of a randomized subset of at least 8,000 participants 18 years and older in the Phase II/III study demonstrates that the vaccine was well tolerated, with most solicited adverse events resolving shortly after vaccination.
The only Grade 3 (severe) solicited adverse events greater than or equal to 2% in frequency after the first or second dose were fatigue at 3.8% and headache at 2.0% following dose 2.
Investors sent the shares of both companies higher in early trading today. As of 10:15 a.m., BioNTech shares rose 3% from yesterday’s close of $86.93, to $89.79. Pfizer shares rose 2.5% to $36.96 from yesterday’s close of $36.04.
Both the data released today and last week were first disclosed by the companies in press releases. Pfizer and BioNTech said they plan to submit their efficacy and safety data for peer-review in a scientific journal once their analysis of the data is completed.
Pfizer and BioNTech said they expect to produce up to 50 million vaccine doses globally this year, and up to 1.3 billion doses by the end of 2021.
Four Pfizer facilities are part of the manufacturing and supply chain; St. Louis, MO; Andover, MA; and Kalamazoo, MI in the U.S.; and Puurs in Belgium. BioNTech’s German manufacturing sites will also contribute to the global supply of BNT162b2.