This piece has been updated.
Johnson & Johnson announced October 12 that it was placing a “study pause” on Phase 3 trials of its COVID-19 vaccine candidate due to an unexplained illness in one of the participants.
The participant, according to J&J, is currently being reviewed and evaluated by J&J’s Data Safety Monitoring Board as well as its clinical physicians. Citing respect for the participant’s privacy and ongoing review, J&J did not include any specifics about the “serious adverse effect.”
“We must respect this participants privacy,” it said. “We’re also learning more about this participant’s illness, and it’s important to have all the facts before we share additional information.”
In a statement, J&J noted that illnesses and accidents are to be expected, especially in large studies that can involve tens of thousands of patients. Johnson & Johnson’s COVID vaccine candidate is currently in Phase 3 of development, a stage at which researchers typically test thousands of volunteers with the condition for “efficacy and monitoring of adverse reactions,” according to the Food and Drug Administration.
The FDA also notes that typical Phase 3 studies involve “300 to 3,000 volunteers.” J&J’s COVID vaccine candidate study could involve as many as 60,000, according to the National Institute of Health.
Notably, Johnson & Johnson's trial is placebo-controlled: it's unclear from the company statement whether or not the affected participant received the vaccine candidate or not.
The study pause was first reported by Stat News, which received copies of a document sent to outside researchers that noted a “pausing rule” for the study had been met. Johnson & Johnson, in its statement, noted that the condition for the “study pause” was part of J&J’s internal standards for clinical trials, as distinct from a regulatory hold placed on the study by the FDA or some other outside regulatory health authority.
“Johnson & Johnson has robust mechanisms in place to protect the safety of participants in its clinical trials,” the New Jersey-based pharmaceutical company said, noting that while it does inform all of the investigators issuing doses of internal holds, it does not typically communicate study pauses to the public.
In September, fellow drugmaker AstraZeneca suspended its own vaccine development program, which its currently developing with the University of Oxford. According to Reuters, its trials have restarted in Britain, Brazil, South Africa and India but not yet in the United States, owing to a regulatory review. J&J’s vaccine candidate is based on the same modified virus as AstraZeneca’s.
