March 23, 2009
The potential of treatments based on human stem cells is stimulating tremendous excitement and hope for
HD families and researchers. Human stem cell lines derived from skin samples of HD patients or at risk
individuals are particularly exciting.
These cells have many possible applications. They might be directed to become brain cells so the disease
can be studied in a human context, or they might be used to efficiently screen drug candidates to
accelerate the discovery of new treatments.
Stem cells also might be used to treat HD directly by “nursing” diseased brain cells or perhaps
even by
delivering new and healthy neurons to the brain.
These and other therapeutic strategies are at various stages of development and hold great promise.
However, we remain cautious in our efforts to ensure that stem cell–based treatments are truly safe as
well
as effective. A recent trial in Russia, where nervous system tumors developed in a child given “neural
stem cells”, highlights the critical importance of safety regulations. Exciting as they are, stem cell-based
approaches require extensive study and evaluation in animal models of HD and caution before testing in
human patients.
The information regarding this trial and guidelines from the International Society for Stem Cell Research
is attached below.
Sincerely,
Leslie Michels Thompson, PhD Jan Nolta, PhD Steven Finkbeiner, MD, PhD
Professor Professor Director, Taube-Koret Center for
Director, Interdepartmental Director, Huntington’s Disease Research
Neuroscience Program Stem Cell Program Associate Investigator, Gladstone Institute
UC Irvine UC Davis Professor, UCSF
Paul Muchowski, PhD Vicki Wheelock, MD
Co-Director, Taube-Koret Center for Associate Clinical Professor
Huntington’s Disease Research Director, HDSA Center of Excellence at
Associate Investigator, Gladstone Institute UC Davis
Associate Professor, UCSF
, released
in December 2008.
The article, appearing in PLoS Medicine (Feb. 17, 2009), documents the development of glioneuronal neoplasms
in the brain and spinal cord of a child from Israel with Ataxia Telangiectasia who, against his doctors'
recommendations, had received multiple injections of "fetal neural stem cells" at a clinic in Russia. No
improvement was seen in the patient's condition, which is a rare disease that causes degeneration in the part
of
the brain that controls movement and speech. The cells that were injected were described as "fetal neural stem
cells," but the exact nature of the cells, quality control procedures and evidence of safety and effectiveness
from
preclinical studies were not available.
The ISSCR reiterates that these findings do not mean that research into potential stem cell therapies should
be
abandoned. This case does, however, emphasize the importance of appropriate preclinical studies for both safety
and effectiveness and the need to exercise extreme caution before stem cell therapies are administered to
humans. It also highlights the need for disclosure of risks to potential patients and the need for those seeking
such
therapies to become fully informed about the nature of the product they are considering.
The ISSCR
provide a roadmap for the responsible
development of safe and effective stem cell therapies for patients. These guidelines call for rigorous standards
in
the development of such therapies including stringent evaluation and oversight, a thorough informed consent
process, and transparency in operations and reporting. The ISSCR once more calls for greater awareness and
international dialogue to help implement the standards described in its guidelines.
"This is a new area of science and its enormous potential is well recognized by the public at large," said David
Scadden, co-chair of the ISSCR Clinical Translation Committee, director of the Massachusetts General Hospital
Center for Regenerative Medicine, and co-director of the Harvard Stem Cell Institute. "What is less well understood
are the potential risks and it is therefore of paramount importance that scientists, physicians and patients
alike
proceed with great care and adhere to the highest ethical and scientific standards."
The ISSCR guidelines provide information for patients and their doctors evaluating a stem cell therapy in Appendix
1, a
