On September 23, Johnson & Johnson initiated a “pivotal” global phase 3 clinical trial of its vaccine candidate. It became the fourth company to do so in the United States. Though Johnson & Johnson reached the phase 3 milestone a few months behind competitors, its advanced vaccine trial promises to be the largest with 60,000 participants.
What is Johnson & Johnson’s Experimental Vaccine?
Johnson & Johnson’s experimental vaccine, known as Ad26.COV2.S, uses vaccine technology with a long record of safety in vaccines for other diseases. This gives J&J a significant advantage over other pharmaceutical companies testing vaccine technologies without established safety protocols.
Ad26.COV2.S uses adenoviral vectors known to be so efficient that J&J’s vaccine could be one of the few to only require one shot instead of two.
Ad26 normally causes common colds, but is disabled to stop replication. A gene for the surface protein from COVID-19 is “stitched” into the Ad26 vector. As Paul Stoffels, J&J’s chief scientific officer explains, “We learned from what we did in Zika that with the right [Ad26] vector, we can get very significant immunity. We can do it with one dose, but we’re going to test two doses in the clinic.”
J&J’s experimental vaccine offers another major benefit over the others: it does not have to be kept frozen in transport to hospitals and medical clinics. This dramatically simplifies the logistics of supply hundreds of millions of vaccine doses.
What We Know About the Phase 3 Clinical Trial
Johnson & Johnson’s Phase 3 Trial, ENSEMBLE, is a large-scale, multi-country trial that plans to enroll up to 60,000 volunteers across three continents. This randomized, double-blind, placebo-controlled clinical trial will evaluate the safety and efficacy of a single vaccine dose versus placebo.
ENSEMBLE participants will all be adults 18 years of age and older, with significant representation from those over age 60. Participants are being enrolled from the United States, Argentina, Brazil, Chile, Colombia, Mexico, Peru, and South Africa.
Johnson & Johnson is collaborating with the Biomedical Advanced Research and Development Authority (BARDA) to initiate ENSEMBLE.
“With our vaccine candidate now in our global Phase 3 trial, we are one step closer to finding a solution for COVID-19. We used a highly scientific and evidence-based approach to select this vaccine candidate. We are extremely grateful for the tireless efforts of our researchers and for the vital contributions of those participants who have volunteered to take part in our studies. Together, we are working to help combat this pandemic,” said Mathai Mammen, M.D., Ph.D., Global Head, Janssen Research & Development, LLC, Johnson & Johnson.
The pharmaceutical company hopes to determine by the end of the year whether its experimental vaccine offers the safety and efficacy necessary for FDA approval and large-scale use.
Johnson & Johnson is already manufacturing the vaccine on an industrial scale to build up a supply that can be released immediately if the vaccine is authorized, Dr. Stoffels explained. He expects the company to have tens of millions of doses ready by the end of the year. “Then we can ramp up to many more batches,” he said.