Vanderbilt University Medical Center has begun recruiting up to 250 participants for a Phase 3 clinical trial testing an investigational COVID-19 vaccine candidate developed by the Janssen Pharmaceutical Companies of Johnson & Johnson.

This is the second COVID-19 vaccine candidate being evaluated at VUMC. A Phase 3 clinical trial of an experimental vaccine developed by Moderna Inc. in collaboration with the Vaccine Research Center of the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH) is underway.

The randomized, double-blind, placebo-controlled clinical study of Janssen's vaccine candidate, called the ENSEMBLE trial, will test the safety and efficacy of a single vaccine dose versus inactive placebo in adults 18 years old and older, including those at risk of severe illness if they are infected by the SARS-CoV-2 virus, which causes COVID-19.

"The COVID-19 vaccine landscape is evolving quickly, and we are proud to be conducting additional vaccine clinical trials here at Vanderbilt," said Buddy Creech, MD, MPH, director of the Vanderbilt Vaccine Research Program and associate professor of Pediatric Infectious Diseases.

"Clinical trials are moving quickly, but despite the speed, the trials are being conducted in the same rigorous ways that they always are," Creech said.

The study will be conducted through the NIH-funded Vanderbilt Vaccine and Treatment Evaluation Unit (VTEU) as part of the newly formed COVID-19 Prevention Network (CoVPN). For more information, contact vaccineresearch@vumc.org.

VUMC is one of approximately 200 centers in the United States, South Africa and throughout Central and South America that are participating in the ENSEMBLE trial. Two other sites in the Vanderbilt VTEU network, in Pittsburgh and Lima, Peru, are also participating in the study.

Up to 60,000 volunteers will be enrolled in the trial, which aims to evaluate the effectiveness of the investigational vaccine in countries with a high incidence of COVID-19 and in populations that have been disproportionately impacted by the pandemic.

ENSEMBLE is being initiated in collaboration with NIAID and the Biomedical Advanced Research and Development Authority, part of the U.S. Department of Health and Human Services' Office of the Assistant Secretary for Preparedness and Response.

The Janssen vaccine candidate is a recombinant vector vaccine that uses a human adenovirus to express the SARS-CoV-2 "spike" protein, which the virus uses to attach to and enter human cells. The hope is that the vaccine will trigger the body's immune system to recognize and attack the virus.

Adenoviruses are a group of viruses that cause the common cold. The adenovirus vector used in the vaccine candidate has been modified so that it can no longer replicate in humans or cause disease.

Preclinical findings published in the journal Nature showed that the vaccine candidate induced neutralizing antibody responses in rhesus macaques and provided near-complete protection against virus infection in the lungs and nose following a SARS-CoV-2 challenge.

A combined Phase 1 and Phase 2a clinical trial conducted in the United States and Belgium has also demonstrated positive interim results in terms of safety and immunogenicity.

Participants in the Phase 3 trial will be randomly assigned to receive either a single dose of the investigational Janssen vaccine or a saline (salt-water) placebo. The trial is blinded, meaning that neither the investigators nor the participants will know who is receiving the investigational vaccine.

Participants will be followed closely for safety and to test the efficacy of the vaccine for two years. The goal is to determine if the investigational vaccine can prevent moderate or severe COVID-19 after a single dose.

The study at Vanderbilt is supported in part by NIAID, U.S. Department of Health and Human Services grant UM1AI148452, to the Vanderbilt Vaccine and Treatment Evaluation Unit.

In a news release, Johnson & Johnson said it was committed to bringing an affordable vaccine to the public on a not-for-profit basis for emergency pandemic use and anticipates the first batches of a COVID-19 vaccine to be available for emergency use authorization in early 2021, if proven to be safe and effective.

More information about the trial is available at: www.ensemblestudy.com.