The Niche

FDA puts plan for a neural stem cell trial on hold

The FDA has ordered a halt to NeuralStem’s plans for a neural stem cell trial in Lou Gehrig’s disease (amyotrophic lateral sclerosis). (See the company’s press release as well as a link to its December announcement that it had filed an IND) NeuralStem says that the FDA’s concerns and recommendations can be readily addressed.

Clinical holds are not unusual, especially for novel therapies. In fact, Geron received a clinical hold in May 2008 before ultimately getting permission to proceed in January 2009. In July, Geron plans to use cells derived from embryonic stem cells to treat spinal cord injury. (See the Nature story) I covered the hold in a blog posting, which also contains links to a summary of the FDA advisory meeting on how to evaluate safety risks for cells derived from embryonic stem cells. Hopes were high at that meeting. So was anxiety.

The FDA’s decision to delay NeuralStem’s trial comes just days after descriptions of an unregulated transplant of fetal neural stem cells that developed into tumours in a patient’s brain and spinal cord. The patient, who has a neurodegenerative disease, was taken by his parents for an unregulated stem cell therapy in Moscow. Doctors in Israel found the growths after the patient complained of headaches.

See the Nature News story. Researchers and physicians I spoke to while reporting the story were outraged that the procedure had occurred. They said that there was no evidence that it could help, and that no rigorous safety studies or even cell characterization had been completed. They took pains to distance the procedure from mainstream clinical research, but at the same time emphasized that all novel treatments carry risk.

(See our expert commentary on unregulated stem cell treatments, which has links to guidelines from the International Society for Stem Cell Research)

Stem-cell treatments involving bone marrow are well established, and though evidence of benefit for mesenchymal stem cells is still preliminary (See Nature Reports story), they do not seem to cause harm. Stem-cell treatments for neurodegenerative diseases are still very much at the beginning. Even with rigorous studies, the field will likely have more questions than clarity for some time to come.

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