- Johnson & Johnson has paused vaccinations in all clinical trials of an experimental coronavirus vaccine the company is developing, including a large-scale study begun late last month, after a study participant fell sick with an unexplained illness.
- The drugmaker could not confirm whether the participant had received the vaccine or a placebo, nor did it disclose further details of the case, citing respect for the volunteer's privacy and noting that it's still gathering information. An independent committee overseeing the trial is reviewing the case.
- So-called adverse events are typical occurrences in large clinical programs like J&J's, and even serious illnesses are not uncommon, the company noted. Still, the pause in vaccinations, which was first reported by Stat News Monday evening and later confirmed by the company, is a notable speed bump for one of the higher-profile vaccine development efforts.
While a serious adverse event, and a subsequent study pause, may be usual in clinical testing, the circumstances surrounding coronavirus vaccine trials are anything but.
With the world anxiously awaiting an effective vaccine to blunt a still raging pandemic, the twists and turns of drug development are magnified. J&J acknowledged as much in even disclosing the study pause, something the company noted it typically doesn't communicate publicly for its clinical trials.
J&J is currently testing its vaccine candidate in four trials, including a Phase 3 trial that's enrolling some 60,000 volunteers across the U.S., South Africa and a half dozen South American countries.
The participant who became ill appears to have been enrolled in that late-stage study. Trial rules made public by J&J describe the scenarios in which vaccinations may be halted for a safety review, including in the case of a serious adverse event.
A panel of independent experts, known as the data safety and monitoring board, is tasked with reviewing the case and making recommendations on how to proceed. Depending on the case and the strength of its connection to vaccination, a halt could prove fleeting, or be more lasting.
"We know very little at this point," said Mathai Mammen, head of research and development at J&J's Janssen unit, on a conference call Tuesday. "It will be a few days at minimum for the right set of information to be gathered and evaluated."
With the halt, J&J's program is now the second to be stopped for a safety review. On Sept. 8, British drugmaker AstraZeneca, which is also among the leading coronavirus vaccine developers, stopped vaccinations in all of its studies worldwide after one participant in the U.K. experienced an unexplained neurological illness. Symptoms were reportedly consistent with transverse myelitis, an inflammation of the spinal cord that can damage the protective sheath surrounding nerve cell fibers.
While studies in the U.K., Brazil, South Africa and India have since been cleared to restart, the company's large U.S. trial remains on hold, amid reports of a widening investigation by the Food and Drug Administration.
Both J&J's and AstraZeneca's vaccine candidates rely on what are known as adenoviruses to shuttle genetic instructions that train the body's immune system against the coronavirus. AstraZeneca's shot, which was invented by the University of Oxford, uses an engineered version of a chimpanzee adenovirus, while J&J uses a Type 26 adenovirus in its vaccine. (J&J uses the same platform for its Ebola vaccine, which was recently approved in Europe.)
Results from earlier trials of both vaccines have shown some promise, indicating vaccination can prompt an immune response in healthy adults without many severe side effects, at least among the smaller groups tested first. Data to date does not, however, yet prove either vaccine to be protective in humans against coronavirus infection or COVID-19.
J&J's Phase 3 study, should it resume and recruit its planned 60,000 participants, is the largest coronavirus vaccine trial started for the dozens of candidates now in human testing. Researchers began vaccinating volunteers in the study on Sept. 23, but it's not clear how many people have been enrolled so far.
According to the trial's plan, researchers would first enlist 2,000 volunteers between the ages of 18 and 60 without any comorbidities. The data monitoring board is then supposed to meet to review safety data over the first three days post vaccination for that group, before opening the trial for further enrollment.
The company did not clarify when asked by BioPharma Dive for comment on enrollment numbers.
J&J's shot has been highly regarded, given the company's experience with vaccines and the potential for it to be given as a single dose. By contrast, vaccines developed by Pfizer and Moderna, considered to be closest to a potential approval, are given as two shots.
Pfizer and Moderna's candidates use a different type of vaccine technology than J&J's and AstraZeneca's, however. Data from a Phase 3 trial being run by Pfizer could be available by late October, while Moderna expects results from its late-stage study in November.
Editor's note: This story has been updated with comments from Johnson & Johnson executives and to reflect the company's response to BioPharma Dive's questions.