The vaccine candidate was more than 90% effective in preventing Covid-19 in participants without prior SARS-CoV-2 infection


Pfizer, BioNTech unveils Phase 3 interim analysis of Covid-19 vaccine. (Credit: fernando zhiminaicela from Pixabay.)

Pfizer and BioNTech unveiled positive results for their mRNA-based Covid-19 vaccine candidate BNT162b2 in the first interim efficacy analysis from the Phase 3 clinical study.

The interim analysis conducted by an external, independent Data Monitoring Committee (DMC) found that the potential vaccine candidate was more than 90% effective in preventing Covid-19 in participants without prior SARS-CoV-2 infection.

Pfizer and BioNTech have recently called off the proposed interim analysis in 32-cases, to conduct the first interim analysis in at least 62 cases, following discussion with the FDA.

After the conclusion of discussions with the US regulator, the DMC has performed the first interim analysis on all of the 94 evaluable cases.

In the first interim analysis, the vaccine was effective in more than 90% individuals at seven days after the second dose (28 days after the first dose) vaccination, compared to those who received the placebo.

The companies said that the analysis did not report any serious safety concerns and the final efficacy percentage of the vaccine may change as the study continues.

Pfizer chairman and CEO Albert Bourla said: “Today is a great day for science and humanity. The first set of results from our Phase 3 Covid-19 vaccine trial provides the initial evidence of our vaccine’s ability to prevent Covid-19.

“We are reaching this critical milestone in our vaccine development program at a time when the world needs it most with infection rates setting new records, hospitals nearing over-capacity and economies struggling to reopen.

“With today’s news, we are a significant step closer to providing people around the world with a much-needed breakthrough to help bring an end to this global health crisis. We look forward to sharing additional efficacy and safety data generated from thousands of participants in the coming weeks.”

More than 43,500 members participated in Phase 3 BNT162b2 trial

The Phase 3 clinical study of BNT162b2 was initiated on 27 July 2020, enrolling 43,538 participants to date. The trial is continuing to enrol patients, aiming to reach a final analysis of a total of 164 confirmed Covid-19 cases.

Also, the study is expected to evaluate the vaccine’s protection in people exposed to prior SARS-CoV-2 infection, along with protection against severe Covid-19 disease.

Apart from the primary efficacy endpoints, the final analysis will include new secondary endpoints evaluating the efficacy of the vaccine, at 14 days after the second dose.

The companies said that the addition of new secondary endpoints will enable alignment of data across all Covid-19 vaccine studies and facilitate cross-trial learnings and comparisons between novel vaccine platforms.

Pfizer and BioNTech claimed that they are working together to submit the required safety and manufacturing data of the vaccine product to the FDA.

BioNTech co-founder and CEO Ugur Sahin said: “The first interim analysis of our global Phase 3 study provides evidence that a vaccine may effectively prevent COVID-19. This is a victory for innovation, science and a global collaborative effort,” said Prof. When we embarked on this journey 10 months ago this is what we aspired to achieve.

“Especially today, while we are all in the midst of a second wave and many of us in lockdown, we appreciate even more how important this milestone is on our path towards ending this pandemic and for all of us to regain a sense of normality.

“We will continue to collect further data as the trial continues to enrol for a final analysis planned when a total of 164 confirmed COVID-19 cases have accrued. I would like to thank everyone who has contributed to make this important achievement possible.”