J&J launches Phase III trial of single-shot Covid-19 vaccine

The placebo-controlled trial, ENSEMBLE, will enroll up to 60,000 healthy volunteers on three continents. The trial will test the vaccine JNJ-78436735, also known as Ad26.COV2.S.

With multiple Phase III trials of vaccines against the virus that causes Covid-19 underway, one developer has started its own late-stage trial of a candidate that may have a convenience advantage over the others.

New Brunswick, New Jersey-based Johnson & Johnson said Wednesday that it had started the Phase III ENSEMBLE trial of JNJ-78436735, also known as Ad26.COV2.S, its vaccine against the SARS-CoV-2 virus. The trial will enroll up to 60,000 healthy volunteers and compare the vaccine against placebo.

In particular, the vaccine is administered in a single shot, unlike other vaccine candidates that are administered as a primer shot, followed by a booster shot several weeks later. The company added that it has submitted Phase I/IIa data on the vaccine to the preprint server medRxiv and expects them to be posted imminently.

“As Covid-19 continues to impact the daily lives of people around the world, our goal remains the same – leveraging the global reach and scientific innovation of our company to help bring an end to this pandemic,” J&J CEO Alex Gorsky said in a statement. “As the world’s largest healthcare company, we are bringing to bear our greatest scientific minds and rigorous standards of safety, in collaboration with regulators, to accelerate the fight against this pandemic.”

So far, the company has released preclinical data showing the vaccine to be effective in animal models.

Meanwhile, numerous vaccine developers have announced data from early trials showing that their vaccines have produced neutralizing antibodies against SARS-CoV-2, at higher concentrations than those found in patients with Covid-19 who have recovered from the disease, as well as producing T-cell responses. Whether that leads to long-term immunity, however, remains to be seen.

The World Health Organization lists a number of vaccines that are currently in Phase III development, current as of Tuesday. These include AstraZeneca and the University of Oxford’s study, which has run into problems due to an adverse event, as well as those of Moderna and the National Institute of Allergy and Infectious Diseases, Pfizer and BioNTech, J&J’s Janssen Pharmaceutical Companies and several companies and institutions abroad like China’s Sinovac and CanSino Biologics and Russia’s Gamaleya Research Institute.

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