Novavax Initiates COVID-19 Vaccine Booster Study in Adolescents in Phase 3 Trial

Novavax has initiated the administration of the first booster dose of NVX-CoV2373, a protein-based COVID-19 vaccine, in the pediatric expansion of the PREVENT-19 phase 3 clinical trial.

The expansion will evaluate the immunogenicity and safety of a third dose of the vaccine among children aged 12 to 17 years.

“We see the ongoing need for alternative vaccine options, because we are continuing to monitor spikes in COVID-19,” Gregory Glenn, MD, president of research and development at Novavax, said in a statement. “The expansion of our PREVENT-19 booster trial into the pediatric population reinforces our commitment to seek to make our vaccine available to a broader population.”

NVX-CoV2373 is a protein-based vaccine that was engineered from the genetic sequence of the first strain of SARS-CoV-2 and was formulated with the company’s patented saponin-based Matrix-M adjuvant, which enhances the immune response and stimulated high levels of neutralizing antibodies.

All individuals in the PREVENT-19 trial are eligible to receive that third booster dose of the vaccine.

The booster dose is identical to the active vaccine that was previously administered in the 2-dose regimen. It is 5 mg of recombinant spike protein with 50 mg of Matric-M adjuvant.

The booster dose can be administered at least 5 months after receiving the active vaccine. The post-booster objectives include the assessment of the humoral immune response 28 days after the administration of the booster dose, as well as describing COVID-19 disease.

Initial results are expected during the second half of 2022.

In the PREVENT-19 trial, investigators aimed to evaluate the efficacy, immunogenicity, and safety of the vaccine with Matrix-M adjuvant in 29,960 individuals aged 18 years or older in 119 locations throughout Mexico and the United States.

The primary endpoint for the study was the first occurrence of polymerase chain reaction (PCR)-confirmed symptomatic COVID-19 with onset at least 7 days after the second dose in serologically negative adult individuals at baseline. A secondary endpoint was the prevention of PCR-confirmed, symptomatic moderate or severe COVID-19.

Both endpoints were assessed at least 7 days after the second study vaccination in individuals who were previously infected with SARS-CoV-2.

In the trial, investigators found that the vaccine achieved an approximately 90.4% efficacy overall.

Additionally, it was well-tolerated and elicited a robust antibody response after the second dose in both studies.

The full results were published in the New England Journal of Medicine (NEJM).

An additional trial, which achieved an efficacy of approximately 89.7%, was conducted in the United Kingdom and included 14,039 individuals aged 18 years or older

The primary endpoint was the same as the PREVENT-19 trial. Full results of this study were also published in NEJM.

The vaccine is packaged as a ready-to-use liquid formulation in a vial containing 10 doses. The regimen calls for 2 0.5 ml doses that is given intramuscularly, with each dose 21 days apart.

The FDA has not yet authorized NVX-CoV2373 for use in the United States.

Reference

Novavax announces initiation of COVID-19 vaccine booster study in adolescents in phase 3 PREVENT-19 trial. Novavax. News release. April 22, 2022. Accessed April 22, 2022. https://ir.novavax.com/2022-04-22-Novavax-Announces-Initiation-of-COVID-19-Vaccine-Booster-Study-in-Adolescents-in-Phase-3-PREVENT-19-Trial