FDA Will Heavily Investigate AstraZeneca Vaccine Safety Issue, Hahn Says

Health regulators abroad have begun giving the OK for AstraZeneca to resume its phase 3 COVID-19 vaccine trial following a single unexplained patient illness, but the FDA has still not cleared the trial to start back up, with FDA Commissioner Stephen Hahn saying the agency will engage in “very significant work” with the company to unravel the safety issue.

Hahn said during an interview with Sen. Tim Scott (R-S.C.) that the FDA will be devoting serious effort to helping the British drugmaker conclude “if there’s a significant safety issue or not.” The agency’s concern revolves around a serious adverse event in a UK patient enrolled in AstraZeneca’s late-stage vaccine trial, the cause of which has not yet been determined (DID, Sept. 9).

“We don’t have all the facts, so we don’t know the causation per se of this, but we really need to look into it,” Hahn said. “What FDA does is we take our responsibilities around safety very seriously. We need to take it all seriously no matter where it occurred.”

AstraZeneca told FDAnews Wednesday it had nothing new to share on the trial pause in the U.S. and cannot provide details on its discussions with regulators, including the FDA.

Hahn reiterated in his remarks that the agency will only approve or authorize a COVID-19 vaccine if it is found safe and effective through proper research, addressing concerns that the agency could give in to pressure from the Trump administration to deliver a vaccine before the presidential election (DID, Aug. 7).

The Drugs Controller General of India (DCGI) is the latest health regulator to allow research on the promising vaccine candidate to resume, giving the Serum Institute of India the go-ahead Tuesday to start its trial back up. UK, Brazilian and South African trials have also begun again.

The FDA declined to comment further on its investigation into the vaccine safety issue. The National Institutes of Health has started its own investigation, according to an agency investigator, though it’s still in the early stages. The medical research agency has expressed great concern about the situation and urged AZ to share more details about the adverse event (DID, Sept. 16).

AstraZeneca previously confirmed it initiated a short trial pause in July so a safety review could take place. One volunteer was confirmed to have an undiagnosed case of multiple sclerosis that was unrelated to AZ’s vaccine (DID, Sept. 10).

In addition, the University of Oxford initiated safety reviews when some volunteers in its phase 2/3 trial, which is being run with the Jenner Institute, experienced unexplained neurological symptoms, including changed sensation or limb weakness. The university paused the study of its COVID-19 vaccine candidate, which AstraZeneca is licensing, to investigate and ultimately found the vaccine was most likely not to blame, though some results were inconclusive.

“After independent review, these illnesses were either considered unlikely to be associated with the vaccine or there was insufficient evidence to say for certain that the illnesses were or were not related to the vaccine,” the university said in the trial’s participant information sheet. “In each of these cases, after considering the information, the independent reviewers recommended that vaccinations should continue.”

The university did not provide dates for the safety issues and did not immediately respond for comment. — James Miessler