Positive Data in Hand, Novavax Eyes Adolescent COVID-19 Vaccine Approval
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Novavax's Phase III trial of its candidate COVID-19 vaccine has demonstrated promising results in adolescents aged 12 to 17 years old in the United States.
NVX-CoV2373, a recombinant nanoparticle protein-based vaccine, achieved an 80% overall efficacy during the PREVENT-19 pivotal Phase III trial, which was conducted at the time the SARS-CoV-2's Delta variant was the predominant strain (from May 24 to September 27, 2021). The trial involved 2,247 adolescents in 73 states.
In the placebo-controlled study, the participants were randomized 2:1 to receive either active NVX-CoV2373 or a placebo and then later underwent blinded crossover after gathering the required safety data. The vaccine was given with the Matrix-M adjuvant, Novavax's patented saponin-based product that helps stimulate antigen entry into the injection site with the goal to boost immune response.
The vaccine achieved a 79.5% overall protective efficacy during the placebo-controlled period, consistent across age groups and cases. The researchers observed robust immune responses among the adolescent group of 2x to 3x higher than in adults and with 100% seroconversion against all variants after receiving two-dose series.
The pediatric trial is an expansion of the primary PREVENT-19 Phase III study in adults aged 18 years and up, which involved around 30,000 participants in Mexico and the U.S. The trial, which was published in The New England Journal of Medicine, demonstrated a 90.4% overall efficacy, plus positive tolerability and safety profiles. Some adverse reactions were noted, such as nausea or vomiting, myalgia, arthralgia, headache, malaise and fatigue, but the numbers were minor.
The promising results from the pediatric expansion are what fuels Novavax's next move to apply for regulatory approval for the 12-to-17-year age group by the first quarter of 2022. The company is also preparing to conduct more studies on a global scale by the second quarter.
So far, NVX-CoV2373's authorizations are for the over-18 group. It has a conditional marketing authorization from the Medicines and Health products Regulatory Agency and the European Commission and an emergency use listing (EUL) from the World Health Organization. With its WHO EUL, the vaccine has the potential to be used in more than 170 countries, covering more than six billion people. In the U.S., the Food and Drug Administration is still also reviewing the vaccine for adult use.
"We are encouraged by the results in this adolescent population given the ongoing need for alternative vaccine options for COVID-19. We believe the Novavax vaccine offers a differentiated technology and option for this younger population given its established protein-based technology already used in other vaccines and the positive responses demonstrated against variants," said Dr. Filip Dubovsky, the chief medical officer of Novavax, in a statement.
NVX-Cov2373 is packaged as a ready-to-use liquid formulation in a vial that contains 10 doses. The regimen requires two 0.5 ml doses, consisting of 5 mcg antigen and 50 mcg Matrix-M in a dose, to be administered via intramuscular injection 21 days apart. Novavax has a manufacturing partnership with Serum Institute of India, but this will later be expanded as more manufacturing sites are introduced.