Johnson & Johnson temporarily pauses Covid-19 vaccine trial after participant falls ill, review being held

The phase 3 study is designed to evaluate the safety and efficacy of a single vaccine dose versus placebo in up to 60,000 adults 18 years old and older, including significant representation from those that are over age 60


                            Johnson & Johnson temporarily pauses Covid-19 vaccine trial after participant falls ill, review being held
(Getty Images)

Johnson & Johnson has temporarily halted its coronavirus vaccine trial due to an unexplained illness in a study participant, the company said in a statement. The pause implies that the online system used to enroll participants has been closed for the 60,000-patient clinical trial while an independent patient safety committee reviews what happened.

“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. Following our guidelines, the participant’s illness is being reviewed and evaluated by the ENSEMBLE independent Data Safety Monitoring Board (DSMB) as well as our internal clinical and safety physicians,” said the statement issued on October 12. 

The company did not divulge any further information about the patient. “We must respect this participant’s privacy. We’re also learning more about this participant’s illness, and it’s important to have all the facts before we share additional information,” it said.

Johnson & Johnson emphasized that adverse events — illnesses, accidents, even those that are serious — are an expected part of any clinical study, especially large studies. “Based on our strong commitment to safety, all clinical studies conducted by the Janssen Pharmaceutical Companies of Johnson & Johnson have prespecified guidelines. These ensure our studies may be paused if an unexpected serious adverse event (SAE) that might be related to a vaccine or study drug is reported, so there can be a careful review of all of the medical information before deciding whether to restart the study,” the company stated. It added, “SAEs are not uncommon in clinical trials, and the number of SAEs can reasonably be expected to increase in trials involving large numbers of participants. Further, as many trials are placebo-controlled, it is not always immediately apparent whether a participant received a study treatment or a placebo.”

Johnson & Johnson said that adverse events — illnesses, accidents, even those that are serious — are an expected part of any clinical study, especially large studies. (Getty Images)

The company also explained the difference between a “study pause“ and a “clinical hold.” The latter is a formal requirement by a regulatory health authority, such as the US Food and Drug Administration (FDA). The vaccine study is not currently under a clinical hold. Johnson & Johnson said that while it normally communicates clinical holds to the public, it does not usually inform the public of study pauses.

“While these terms are sometimes used interchangeably, there is a significant distinction between a study pause and a regulatory hold of a clinical trial. A study pause, in which recruitment or dosing is paused by the study sponsor, is a standard component of a clinical trial protocol. As noted in the study protocol, Johnson & Johnson has robust mechanisms in place to protect the safety of participants in its clinical trials. While the company informs all study investigators, we typically do not communicate study pauses publicly. As outlined in our transparency commitments, we proactively disclose any regulatory hold of a pivotal clinical trial,” the statement clarified. 

The phase 3 trial is being conducted in collaboration with “Operation Warp Speed,“ a multi-agency collaboration overseen by US Department of Health and Human Services (HHS) and the Department of Defense that aims to accelerate the development, manufacturing and distribution of medical countermeasures for coronavirus.

According to the company, the phase 3 ENSEMBLE study is a randomized, double-blind, placebo-controlled clinical trial designed to evaluate the safety and efficacy of a single vaccine dose versus placebo in up to 60,000 adults 18 years old and older, including significant representation from those that are over age 60. The trial will include those both with and without comorbidities associated with an increased risk for progression to severe Covid-19, and will aim to enroll participants in the US, Argentina, Brazil, Chile, Colombia, Mexico, Peru, and South Africa. To evaluate the effectiveness of Janssen’s coronavirus vaccine, countries and clinical trial sites which have a high incidence of Covid-19 and the ability to achieve a rapid initiation will be activated, stated Johnson & Johnson on September 23. 

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