Pfizer Inc. (NYSE: PFE) and BioNTech SE (Nasdaq: BNTX) announced the initiation of a clinical study to evaluate the safety, tolerability and immunogenicity of an Omicron-based vaccine candidate in healthy adults 18 through 55 years of age. The study will have three cohorts examining different regimens of the current Pfizer-BioNTech COVID-19 vaccine or an Omicron-based vaccine. The study will draw upon some participants from the companies' Phase 3 COVID-19 booster study and is part of their ongoing efforts to address Omicron and determine the potential need for variant-based vaccines.

"While current research and real-world data show that boosters continue to provide a high level of protection against severe disease and hospitalization with Omicron, we recognize the need to be prepared in the event this protection wanes over time and to potentially help address Omicron and new variants in the future," said Kathrin U. Jansen, Ph.D., Senior Vice President and Head of Vaccine Research & Development at Pfizer. "Staying vigilant against the virus requires us to identify new approaches for people to maintain a high level of protection, and we believe developing and investigating variant-based vaccines, like this one, are essential in our efforts towards this goal."

"Vaccines continue to offer strong protection against severe disease caused by Omicron. Yet, emerging data indicate vaccine-induced protection against infection and mild to moderate disease wanes more rapidly than was observed with prior strains,” said Prof. Ugur Sahin, CEO and Co-founder of BioNTech. "This study is part of our science-based approach to develop a variant-based vaccine that achieves a similar level of protection against Omicron as it did with earlier variants but with longer duration of protection."

The study will evaluate up to 1,420 participants across the three cohorts:

• Cohort #1 (n = 615): Received two doses of the current Pfizer-BioNTech COVID-19 vaccine 90-180 days prior to enrollment; in the study, participants will receive one or two doses of the Omicron-based vaccine

• Cohort #2 (n = 600): Received three doses of the current Pfizer-BioNTech COVID-19 vaccine 90-180 days prior to enrollment; in the study, participants will receive one dose of the current Pfizer-BioNTech COVID-19 vaccine or the Omicron-based vaccine

• Cohort #3 (n=205): Vaccine-na?ve participants will receive three doses of the Omicron-based vaccine

Clinical and real-world data continue to find people who are vaccinated, particularly those that have received a booster, maintain a high level of protection against Omicron, particularly against severe disease and hospitalization. The companies have previously announced that they expect to produce four billion doses of the Pfizer-BioNTech COVID-19 Vaccine in 2022, and this capacity is not expected to change if an adapted vaccine is required.

The Pfizer-BioNTech COVID-19 Vaccine, which is based on BioNTech's proprietary mRNA technology, was developed by both BioNTech and Pfizer. BioNTech is the Marketing Authorization Holder in the United States, the European Union, the United Kingdom, Canada and other countries, and the holder of emergency use authorizations or equivalents in the United States (jointly with Pfizer) and other countries. Submissions to pursue regulatory approvals in those countries where emergency use authorizations or equivalent were initially granted are planned.

About Pfizer: Breakthroughs That Change Patients' Lives

At Pfizer, we apply science and our global resources to bring therapies to people that extend and significantly improve their lives. We strive to set the standard for quality, safety and value in the discovery, development and manufacture of health care products, including innovative medicines and vaccines. Every day, Pfizer colleagues work across developed and emerging markets to advance wellness, prevention, treatments and cures that challenge the most feared diseases of our time. Consistent with our responsibility as one of the world's premier innovative biopharmaceutical companies, we collaborate with health care providers, governments and local communities to support and expand access to reliable, affordable health care around the world. For more than 170 years, we have worked to make a difference for all who rely on us.

About BioNTech

Biopharmaceutical New Technologies is a next generation immunotherapy company pioneering novel therapies for cancer and other serious diseases. The Company exploits a wide array of computational discovery and therapeutic drug platforms for the rapid development of novel biopharmaceuticals. Its broad portfolio of oncology product candidates includes individualized and off-the-shelf mRNA-based therapies, innovative chimeric antigen receptor T cells, bi-specific checkpoint immuno-modulators, targeted cancer antibodies and small molecules. Based on its deep expertise in mRNA vaccine development and in-house manufacturing capabilities, BioNTech and its collaborators are developing multiple mRNA vaccine candidates for a range of infectious diseases alongside its diverse oncology pipeline. BioNTech has established a broad set of relationships with multiple global pharmaceutical collaborators, including Genmab, Sanofi, Bayer Animal Health, Genentech, a member of the Roche Group, Regeneron, Genevant, Fosun Pharma and Pfizer.