Johnson & Johnson pauses COVID-19 vaccine trial after patient's 'unexplained illness'

October 13, 2020
Chris Mazzolini

Chris Mazzolini is the editorial director of Medical Economics

The company says it is investigating before determining next steps in the COVID-19 vaccine trial.

Johnson & Johnson announced Monday that the company is pausing its phase 3 COVID-19 vaccine trial after a clinical trial participant contracted an "unexplained illness," the company said in a statement.

The pause in the closely watched trial, dubbed ENSEMBLE, was first reported by STAT News.

"We have temporarily paused further dosing in all our COVID-19 vaccine candidate clinical trials, including the Phase 3 ENSEMBLE trial, due to an unexplained illness in a study participant," the company statement read.

The company said that such outcomes are common in clinical trials, and stressed the difference between a study pause — which could be a short and only temporary occurence — and a regulatory hold, which is a formal action by the FDA that can mean much longer delays.

The company said it is undertaking a "careful review of all of the medical information before deciding whether to restart the study."

The ENSEMBLE trial began in late September, and is one of nearly a dozen phase 3 trials as pharmaceutical companies race to develop a COVID-19 vaccine, according to a tracking database published by the New York Times. ENSEMBLE involves more than 60,000 volunteer patients across three continents.

It is not the only COVID-19 vaccine trial that has had to halt investigations. In early sepetmber, the vaccine candidate from AstraZeneca and Oxford University paused for a "side effect" experienced by a patient. That trial resumed about a week later in the United Kingdom, but remains on hold in the United States.