Four experimental coronavirus shots have now entered Phase 3 testing in the U.S.
Johnson & Johnson JNJ +0.24% said Wednesday it started a 60,000-person clinical trial of its single-dose Covid-19 vaccine on three continents, becoming the fourth experimental Covid-19 shot to enter final-stage testing in the U.S.
The New Brunswick, N.J., company said it could learn pivotal results from the trial by early next year, which if positive could lead to government authorization of the vaccine for emergency use soon afterward. J&J aims to enroll adult volunteers in the U.S. and several other countries, including Brazil and South Africa.
The trial follows an earlier study in which the shot showed promising results. It will now test whether a single dose of J&J’s vaccine can safely protect people from Covid-19. U.S. government agencies including the National Institutes of Health and the Department of Health and Human Services are helping to fund the study, which is expected to cost about $480 million.
Pfizer Inc. and partner BioNTech SE also started a Phase 3 trial of their vaccine in July and have enrolled nearly 32,000 toward a goal of 44,000. Interim results of the Moderna and Pfizer studies could come as soon as October, but possibly later, according to company executives.
AstraZeneca PLC, which licensed a vaccine from the University of Oxford, started a 30,000-person Phase 3 trial in the U.S. in August but that study is on hold while an independent committee reviews a safety matter.
J&J is collaborating with the U.K. government for a separate Phase 3 study to test a two-dose regimen of the vaccine.
Public-health officials are counting on one or more of these vaccines to pass muster in the large trials and become available to help curb the coronavirus pandemic. The vaccine developers have already started manufacturing doses that could be ready soon after regulators clear a vaccine for use.
“We want to do everything we can without sacrificing safety or efficacy…to make sure that we end up with vaccines that are going to save lives,” NIH Director Francis Collins said in a conference call with reporters.
J&J started work on its vaccine earlier this year and in July started the first study in humans in the U.S. and Belgium.
J&J Chief Scientific Officer Paul Stoffels said the vaccine showed positive interim results in inducing immune responses in the first study, and was generally well-tolerated. Vaccine recipients experienced certain side effects, including fever and flulike symptoms, which Dr. Stoffels said weren’t unusual for vaccines. Dr. Stoffels said full results from the early-stage study would be published online imminently.
In the Phase 3 study, some subjects will receive the vaccine, and others a placebo, and researchers will track whether the rates of symptomatic Covid-19 are lower among vaccinated people than unvaccinated people.
J&J’s vaccine is known as a viral vector shot because it uses a modified adenovirus—a virus that can cause the common cold—to deliver genetic instructions teaching the human immune system to build a defense against the coronavirus.
The company in August signed a $1 billion contract with the federal government to supply 100 million doses for the U.S., if the vaccine proves successful in testing and gets authorized for use. J&J expects to produce more than one billion doses globally during 2021.