Novavax (NSDQ:NVAX) today announced that it has begun its first Phase 3 study to evaluate the efficacy, safety and immunogenicity of its COVID-19 vaccine candidate, NVX-CoV2373.

The trial is underway in the UK, in partnership with the UK government’s Vaccines Taskforce. Gaithersburg, Md.-based Novavax said it expects to enroll up to 10,000 individuals between 18 and 84  years of age, with and without relevant comorbidities, over the next four to six weeks and to make its UK study protocol public “in the coming days.”

“With a high level of SARS-CoV-2 transmission observed and expected to continue in the UK, we are optimistic that this pivotal Phase 3 clinical trial will enroll quickly and provide a near-term view of NVX-CoV2373’s efficacy,” said Novavax R&D president Dr. Gregory M. Glenn, M.D. in a news release. “The data from this trial is expected to support regulatory submissions for licensure in the UK, EU and other countries. We are grateful for the support of the UK government, including from its Department of Health and Social Care and National Institute for Health Research, to advance this important research.”

NVX-CoV2373 is a stable, prefusion protein made using the company’s recombinant protein nanoparticle technology that includes its proprietary MatrixM adjuvant, according to the company. Half of the Phase 3 trial participants will receive two intramuscular injections of vaccine comprising 5 µg of protein antigen with 50 µg Matrix‑M adjuvant, administered 21 days apart, while half of the trial participants will receive a placebo, the company said.

The trial is designed to enroll at least 25% of participants over the age of 65 as well as to prioritize groups that are most affected by COVID-19, including racial and ethnic minorities. Up to 400 participants will also receive a licensed seasonal influenza vaccine as part of a co-administration sub-study.

The trial has two primary endpoints. The first is first occurrence of PCR-confirmed symptomatic COVID-19 with onset at least 7 days after the second study vaccination in volunteers who have not been previously infected with SARS-CoV-2. The second primary endpoint is first occurrence of PCR-confirmed symptomatic moderate or severe COVID-19 with onset at least 7 days after the second study vaccination in volunteers who have not been previously infected with SARS-CoV-2. The primary efficacy analysis will be an event-driven analysis based on the number of participants with symptomatic or moderate/severe COVID-19 disease. An interim analysis will be performed when 67% of the desired number of these cases has been reached.

Novavax has continued to scale-up its manufacturing capacity, currently at up to 2 billion annualized doses, once all capacity has been brought online by mid-2021. The vaccine will allow handling in an unfrozen, liquid formulation that can be stored at 2°C to 8°C (35.6°F to 46.4°F), allowing for distribution using standard vaccine channels, the company said.