Last week, the National Institute of Allergy and Infectious Diseases (NIAID) announced the commencement of the Phase III trial (NCT04611802) of the Novavax investigational COVID-19 vaccine. The trial will evaluate the effectiveness, immune response, and safety of a COVID-19 vaccine candidate called NVX-CoV2373, and is estimated to complete data collection by March 31, 2021.
“Addressing the unprecedented health crisis of COVID-19 has required extraordinary efforts on the part of government, academia, industry and the community,” said NIAID Director Anthony S. Fauci, MD “The launch of this study–the fifth investigational COVID-19 vaccine candidate to be tested in a Phase III trial in the United States–demonstrates our resolve to end the pandemic through development of multiple safe and effective vaccines.”
This NIH (National Institutes of Health) and BARDA (Biomedical Advanced Research and Development Authority)-funded, randomized, placebo-controlled trial is set to enroll up to 30,000 volunteers, at approximately 115 sites in Mexico and the U.S., including the NIAID-supported COVID-19 Prevention Network (CoVPN), headquartered at the Fred Hutchinson Cancer Research Center, that was designed to evaluate vaccine candidates and monoclonal antibodies for COVID-19.
The trial is being conducted in collaboration with Operation Warp Speed (OWS) a multi-agency collaboration overseen by the Department of Health and Human Services (HHS) and the Department of Defense with the aim of accelerating the development, manufacture, and distribution of of COVID-19 vaccines, therapeutics, and diagnostics. All Phase III clinical trials of candidate vaccines supported through OWS are overseen by a common DSMB (Data and Safety Monitoring Board ), developed in consultation with the NIH Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) initiative, that will ensure the safe and ethical conduct of the study.
Participants in the trial will be grouped into two cohorts based on age: 18 to 64 years old, and 65 and older. The organizers aim to prioritize enrollment of individuals at higher risk of COVID-19 disease, including people of African American, Native American, Latino or Hispanic ethnicity, people with health conditions such as obesity, chronic kidney disease or diabetes, and people 65 years and older.
“We’ve come this far, this fast, but we need to get to the finish line,” said NIH Director Francis S. Collins, MD, PhD. “That will require multiple vaccines using different approaches to ensure everyone is protected safely and effectively from this deadly disease.”
Each participant enrolled in the study upon informed consent, will receive two intramuscular injections over the course of the study. After providing a baseline nasopharyngeal and blood sample, participants will be assigned at random to receive an intramuscular injection of either the investigational vaccine or a saline placebo. For every two volunteers who receive the investigational vaccine one volunteer will receive the placebo control.
To eliminate bias, the intervention is quadruple masked with the participant, care provider, investigator, and outcomes assessor unaware of who is receiving the candidate vaccine or the placebo. A second injection will be administered 21 days after the first.
Data will be collected from participants for two years following the second injection. Participants will be monitored for side effects of the vaccine and blood samples will be collected at specified time points to detect and quantify immune responses to SARS-CoV-2, the virus that causes COVID-19. Immune responses resulting from natural infection will be distinguished from vaccine-induced immune responses using specialized assays. The trial’s primary purpose is to determine whether NVX-CoV2373 can prevent symptomatic COVID-19 disease seven or more days after the second injection relative to placebo.
NVX-CoV2373 is made from a stabilized form of the coronavirus spike protein using Novavax’ recombinant protein nanoparticle technology. The purified protein antigens in the vaccine cannot replicate and cannot cause COVID-19. The vaccine also contains a proprietary adjuvant, MatrixMT, that is designed to enhance immune response to the vaccine. NVX-CoV2373 is administered in liquid form and can be stored, handled and distributed above freezing temperatures (35° to 46°F.) A single vaccine dose contains 5 micrograms of protein and 50 micrograms of adjuvant.
Preclinical testing of NVX-CoV2373 vaccination in animals has validated the production of antibodies that block the coronavirus spike protein from binding to the cell surface receptors targeted by the virus, preventing viral infection. Phase I clinical trial results published in the New England Journal of Medicine, show NVX-CoV2373 is generally well-tolerated and elicits higher levels of antibodies than those seen in blood samples drawn from people who had recovered from clinically significant COVID-19.
NVX-CoV2373 is also being evaluated in a Phase IIb trial in South Africa on 4,422 enrolled volunteers; a Phase I/II continuation trial in the United States and Australia that is expected to report results in the first quarter of 2021; and a Phase III trial in the United Kingdom, with more than 15,000 volunteers which is testing the candidate vaccine at the same dosage as this Phase III trial.