On May 3, 2021, Novavax announced that it had initiated a pediatric expansion of its Phase 3 clinical trial for NVX-CoV2373, the company’s recombinant protein vaccine candidate against COVID-19. The additional arm of the ongoing PREVENT-19 pivotal trial evaluated the efficacy, safety and immunogenicity of NVX-CoV2373 in up to 3,000 adolescents aged 12-17 across up to 75 sites in the U.S.

Participants randomly received either the vaccine candidate or placebo in two doses, administered 21 days apart. Two-thirds of volunteers received intramuscular injections of the vaccine and one-third received placebo. A blinded crossover was planned to take place six months after the initial set of vaccinations to ensure that all trial participants received active vaccine. Participants were monitored for safety for up to two years following the final dose.

NVX-CoV2373 is a protein-based vaccine candidate engineered from the genetic sequence of the first strain of SARS-CoV-2, the virus that causes COVID-19 disease. NVX-CoV2373 was created using Novavax’ recombinant nanoparticle technology to generate antigen derived from the coronavirus spike (S) protein and is adjuvanted with Novavax’ patented saponin-based Matrix-M™ to enhance the immune response and stimulate high levels of neutralizing antibodies. NVX-CoV2373 contains purified protein antigen and can neither replicate, nor can it cause COVID-19. In preclinical studies, NVX-CoV2373 induced antibodies that blocked the binding of spike protein to cellular receptors and provided protection from infection and disease. It was generally well-tolerated and elicited robust antibody response in Phase 1/2 clinical testing.

NVX-CoV2373 is being evaluated in two pivotal Phase 3 trials: a trial in the U.K. that demonstrated 100% protection against severe disease, efficacy of 96.4% against the original virus strain, 86.3% against the B.1.1.7/501Y.V1 variant and 89.7% overall; and the PREVENT-19 trial in the U.S. and Mexico that began in December 2020. It is also being tested in two ongoing Phase 2 studies that began in August 2020: A Phase 2b trial in South Africa that demonstrated 100% protection against severe disease and 48.6% efficacy against a newly emerging escape variant first described in South Africa, and a Phase 1/2 continuation in the U.S. and Australia.

NVX-CoV2373 is stored and stable at 2°- 8°C, allowing the use of existing vaccine supply chain channels for its distribution. It is packaged in a ready-to-use liquid formulation in 10-dose vials.