Cysts stall stem cell trial?

Just over a week after the linkurl:Geron Corporation;http://www.geron.com/ announced that the linkurl:US Food and Drug Administration;http://www.fda.gov/ (FDA) had linkurl:placed a hold on its stem cell trial;http://www.the-scientist.com/blog/display/55898/ aimed at treating patients with spinal cord injury with human embryonic stem cells (hESCs), the company linkurl:revealed a reason:;http://www.geron.com/media/pressview.aspx?id=1188 microscopic cysts. Human embryonic stem cellsImage: Wikimedi

Jef Akst

| 1 min read

Human embryonic stem cells
Image: Wikimedia commons,
Nissim Benvenisty

The cysts had appeared with a "very low frequency" in previous animal experiments of the drug GRNOPC1, but were "non-proliferative, confined to the injury site, and had no adverse effects on the animals," Geron's statement said. In a more recent animal trial, however, the cysts showed up more often, although again, they were small and did not appear to be harmful in any way. In fact, the statement pointed out, cysts are not uncommon in victims of spinal cord injury, developing in the spinal cord scar tissue in up to 50% of patients. "I think it provides people with a reasonable explanation," Stephen Brozak, an analyst with WBB Securities LLC in Westfield, New Jersey, linkurl:told Bloomberg.com,;http://www.bloomberg.com/apps/news?pid=20601103&sid=axMDaltRudv4 adding that it was good news that none of the cysts had developed into teratomas. Geron is currently working with the FDA to resolve any issues that would prevent the continuation of the trial. "We are committed to the optimization of all our hESC-based products," they said. The FDA had no comment, according to spokesperson Karen Riley, saying in an email to The Scientist that they "neither confirm nor comment on clinical holds."
**__Related stories:__*** linkurl:Human stem cell trial on hold;http://www.the-scientist.com/blog/display/55898/
[20th August 2009]*linkurl:Geron CEO: Q&A;http://www.the-scientist.com/news/display/55379/
[26th January 2009]*linkurl:Right on Geron;http://www.the-scientist.com/blog/display/55354/
[23rd January 2009]*linkurl:FDA OKs stem cell trial;http://www.the-scientist.com/blog/display/55353/
[23rd January 2009]