By Chris Wack

Pfizer Inc. and BioNTech SE shares rose in premarket trading Monday after the companies said their mRNA-based vaccine candidate, BNT162b2, against SARS-CoV-2 has demonstrated evidence of efficacy against Covid-19 in participants without prior evidence of SARS-CoV-2 infection.

The new data is based on the first interim efficacy analysis conducted Nov. 8 by an external, independent data-monitoring committee from the Phase 3 clinical study.

Pfizer shares were up 12%, to $40.69, in premarket trading, and BioNTech shares were up 15%, to $106, premarket.

The companies said the case split between vaccinated individuals and those who received the placebo indicated a vaccine efficacy rate above 90% at 7 days after the second dose. The data shows that protection is achieved 28 days after the initiation of the vaccination, which consists of a 2-dose schedule. As the study continues, the final vaccine efficacy percentage may vary.

The data-monitoring committee has not reported any serious safety concerns and recommends that the study continue to collect additional safety and efficacy data as planned. The data will be discussed with regulatory authorities worldwide.

"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," said Dr. Albert Bourla, Pfizer chairman and chief executive.

The Phase 3 clinical trial of BNT162b2 began July 27 and has enrolled 43,538 participants to date, 38,955 of whom have received a second dose of the vaccine candidate as of Nov. 8.

Pfizer and BioNTech are continuing to accumulate safety data and currently estimate that a median of two months of safety data following the second dose of the vaccine candidate--the amount of safety data specified by the FDA in its guidance for potential Emergency Use Authorization--will be available by the third week of November. Participants will continue to be monitored for long-term protection and safety for an additional two years after their second dose.

Along with the efficacy data generated from the clinical trial, Pfizer and BioNTech are working to prepare the necessary safety and manufacturing data to submit to the FDA to demonstrate the safety and quality of the vaccine product produced.

Based on current projections, the companies expect to produce globally up to 50 million vaccine doses in 2020 and up to 1.3 billion doses in 2021.

Write to Chris Wack at chris.wack@wsj.com

(END) Dow Jones Newswires

11-09-20 0801ET