LONDON — The first test in humans of a new drug to treat leukemia and autoimmune diseases has left six men severely ill, sparking fresh questions over the safety of such clinical trials.
Four of the men had regained consciousness Friday, doctors said, but two others were in critical condition with multiple organ failure.
The six previously healthy volunteers became seriously ill soon after taking TGN1412, a monoclonal antibody, on Monday in a trial run by Parexel International, based in Waltham, Mass. British regulators ordered an immediate suspension of the tests.
Thomas Hanke, the chief scientific officer of TeGenero AG of Wuerzburg, Germany, which developed the drug, said it had been tested on rabbits and monkeys with no “drug-related adverse events.”
Raste Khan, one of two men given a placebo in the trial, said the six were stricken with vomiting and severe pain within minutes of receiving the drug.
“Everyone was continuously vomiting,” Khan said in an interview broadcast Thursday on Sky News.
They were “fainting, coming back to consciousness. Again I assume they had headaches, because a lot of them were kind of like holding their heads.” He said one man screamed and complained of pain in his back.
Experts in clinical trials said they were shocked at the extreme reactions and questioned why the six men were all given the drug at the same time.
Monoclonal antibodies such as TG1412 can be toxic, while not much is known about them, Martin Glennie, a specialist in monoclonal antibodies at Southampton University said Friday. He said it was unusual to give six subjects doses of the drug at the same time.
“I do not understand why they would give it to six volunteers all at once,” he said.
Chris Hughes, director of the Medical Research Council in Britain, said: “It’s very rare indeed. I have never come across anything like this, nor has anyone I have spoken to.”
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The eight volunteers were paid about $3,500 for what was to have been a two-week trial.
Parexel, the American company that administered the tests, insisted that correct procedures had been followed.
“An initial review at the site to date has shown that best practices were followed and all of the appropriate policies and procedures were adhered to,” said Dr. Herman Scholtz, head of clinical pharmacology at Parexel.
“We are working with the Medicines and Healthcare Products Regulatory Agency in the U.K. to review in detail all of the policies and procedures that were followed,” Scholtz said.
Parexel spokeswoman Jill Baker said the tests followed the protocol agreed with the regulatory agency, which is responsible for authorizing clinical trials.
The agency said Friday that, after preliminary investigations, they found nothing to question their decision to grant Parexel permission to carry out the trial. It said the dose administered to the men was 500 times lower than the highest safe dose given to animals.
The agency authorizes around 1,100 clinical trials in Britain each year. Around 350 are Phase 1, or first-time tests on healthy humans.
Dr. Ganesh Suntharalingam, clinical director of the intensive care unit of London’s Northwick Park Hospital, said the two men who were in critical condition had shown early signs of responding to treatment.
“Their condition remains very serious and complex, and it would not be sensible to comment on prognosis,” he said Friday.
The other four remained in serious condition, Suntharalingam said. Some had made “noticeable progress” in response to treatment, but “it is early days and they will clearly need continued specialist observation for some considerable time,” he said.
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