Human Trial of Embryonic Stem Cell Research Stopped Due to Animal Problems

Bioethics   |   Steven Ertelt   |   Aug 27, 2009   |   9:00AM   |   WASHINGTON, DC

Human Trial of Embryonic Stem Cell Research Stopped Due to Animal Problems

by Steven Ertelt Editor
August 27
, 2009

Washington, DC ( — More information is coming to light about why the Food and Drug Administration has made the decision to stop human trials involving embryonic stem cells. The reasons mirror the concerns pro-life advocates have had for years with the research, which has yet to help any patients.

Geron Corporation had applied for permission to try injections of embryonic stem cells, which can only be obtained by destroying the lives of unborn children at their earliest stage of life, in humans.

But pro-life advocates said they didn’t think it would work because of problems in animals.

When used in animal research, injections of embryonic stem cells formed tumors afterwards and also prompted the immune system of the intended recipients to reject the cells.

The FDA delayed the trials to review studies of the therapy, called GRNOPC1, in its use with animals.

Now, new reports indicate problems associated with the animals in Geron’s studies prompted the FDA to halt the human trials. Specifically, the animals developed cysts at the injury sites after the injections.

Geron tried to play down the concerns and said in a statement that “a very low frequency of injected animals developed microscopic cysts in the regenerating injury site” but the cysts were “non-proliferative, confined to the injury site, and had no adverse effects on the animals."

It added that none of the animals developed teratomas.

“We have submitted these data to the FDA and are in discussions with the agency to answer its questions and proceed with the clinical trial,” Geron said.

Wesley J. Smith, a bioethicist, says he thinks the research done on humans using cells from aborted babies showed eventual problems and he believes the FDA needs to significantly slow down Geron’s plans to proceed quickly.

"You know, tumors formed in a child given fetal cell treatments three years after the injection, and so I wonder how long an animal would have to be followed to determine safety," he said.

"And we can’t forget that the company apparently has not tested the product in large animals, and so there is some swimming in the dark here," he added. "Nevertheless, the FDA did the right thing here in terms of pure safety."

Geron had planned to begin the trials this summer but said it will halt that pending the FDA review and did not know how long it would take the regulatory agency to conduct its evaluation.

The FDA initially cleared the trials in January, which would involve 8 to 10 patients.

Embryonic stem cell research has never cured or helped any patients to this point. Only the use of adult stem cells and treatments derived from them have cured or reduced the effects of any diseases or conditions afflicting patients.

Geron Corp., based in California, will use the treatment with 10 spinal cord patients with injuries the company hopes to treat with an experimental drug containing embryonic stem cells.

The patients in the trial will be ones who can receive treatment within 14 days after a spinal cord injury has left them paralyzed. They will need to be followed for a year to determine if the treatments had any effect.

Evan Snyder, a neuroscientist who heads up the stem cell research center at the Burnham Institute for Medical Research in San Diego, warns that the research may not be ready for humans.

"There’s a lot of debate among spinal cord researchers that the pre-clinical data itself doesn’t justify the clinical trial," Snyder, who is working on using neural stem cells himself, says.

Snyder says the mice Geron used to conduct pre-human trial research had more excessive injuries that scientists would normally prefer to see prior to trying the procedure on human patients.

He suggests that Geron should have done experiments involving larger animals before seeking FDA permission to use the controversial embryonic stem cells in humans.

Those concerns existed as early as 2005 and may not have been addressed.

Snyder said then that Geron should do more animal testing first to make sure the tests would be on the same injuries humans have.

"I’m not convinced they have done that yet," Snyder said.

Jerry Silver, a neuroscience professor and stem-cell researcher at Case Western Reserve University in Cleveland, told Knight Ridder back in November 2005 that Geron was moving too fast and needed to do more tests on animals before seeking human patients.

"Frankly, I cannot conceive of a human trial with the use of human embryonic stem cells following immediately from experiments in rodents only," he said then. "Many treatments that work in rodents to alleviate disease fail miserably in humans."

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