By Peter Loftus 

AstraZeneca PLC said Saturday clinical trials for its experimental coronavirus vaccine have resumed in the U.K. after regulators concluded it was safe to do so, following a pause in studies globally after a person who received the vaccine had an unexplained illness.

Trials in other countries, including the U.S., remain paused while AstraZeneca works with national health authorities, the company said.

AstraZeneca said Tuesday it paused trials globally of a vaccine it licensed from the University of Oxford after a vaccinated woman in the U.K. experienced the unexplained illness, which a U.S. official described as a spinal cord problem.

The pause gave independent committees and country regulators time to evaluate the case and determine whether it would be safe for testing to begin again.

A U.K. committee has concluded its investigation and recommended to the U.K. Medicines & Healthcare products Regulatory Agency it would be safe to resume the trials. The regulatory agency confirmed that it was safe to resume, the company said.

The MHRA couldn't immediately be reached for comment.

AstraZeneca said it couldn't disclose further information about the study subject's illness. Oxford, which is running a U.K. study of the vaccine, said it couldn't disclose medical information about the illness for reasons of participant confidentiality.

The U.K. study of the AstraZeneca/Oxford vaccine was paused once before, in July, after a person in the trial experienced neurological symptoms, which were later diagnosed as multiple sclerosis and deemed unrelated to the vaccine. Testing resumed after the July pause following a safety review.

An information sheet given to study subjects, updated Friday and posted on Oxford's website about the trial, says that researchers have undertaken safety reviews when volunteers in the trials developed unexplained neurological symptoms including "changed sensation" or limb weakness. The document said that after an 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."

Independent reviewers recommended that vaccinations should continue, and they will closely monitor the affected study volunteers and other participants, according to the document.

Also Saturday, Pfizer Inc. and partner BioNTech SE said they asked U.S. regulators to permit expanding the late-stage trial testing for their experimental Covid-19 vaccine to about 44,000 people, up from 30,000.

Pfizer expected to reach its initial target of enrolling 30,000 subjects next week. A larger trial will increase diversity and include people as young as 16 years old, as well as people diagnosed with viral diseases such as HIV, hepatitis C and hepatitis B, the company said.

Pfizer still expected to have results by the end of October, and aimed to file for regulatory authorization or approval, if the results are positive, by the end of October, a company spokeswoman said.

Oxford said Saturday about 18,000 people globally have received its Covid-19 vaccine in trials. Before the study pause, AstraZeneca had started a 30,000-person U.S. trial of the vaccine.

Moderna Inc. said Friday nearly 23,500 people have enrolled in a late-stage study of its vaccine in the U.S., toward a goal of 30,000. The company has said it has asked leaders of its study sites to boost minority enrollment, even if that means taking longer to complete total enrollment in the trial.

Johnson & Johnson plans to start this month a late-stage study of its vaccine in up to 60,000 people in several countries including the U.S.

Jared S. Hopkins contributed to this article.

Write to Peter Loftus at peter.loftus@wsj.com

 

(END) Dow Jones Newswires

September 12, 2020 16:53 ET (20:53 GMT)

Copyright (c) 2020 Dow Jones & Company, Inc.
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