Structure of a typical neuron, showing the protective myelin sheath that is attacked in multiple sclerosis

In what could herald a major advance in treating multiple sclerosis, brain damage was significantly reduced in patients getting stem cell transplants, compared to a control group. Results of the small Phase 2 trial -- the first of its kind -- are preliminary but promising, according to experts not involved with the trial.

The four-year study compared the results of intense immune suppression followed by transplants of the patient's own blood-forming, or hematopoietic stem cells to those of a control group given immune suppression alone. Dr. Giovanni L. Mancardi of the University of Genova in Italy led the 21-patient study, released Wednesday in the journal Neurology.

Patients in the treatment group had 80 percent fewer new damaged brain areas called T2 lesions, compared to those who got the immune-suppressing chemotherapy drug mitoxantrone but no stem cells. The Phase 3 trial will look for signs of effectiveness in reducing disability. The goal is to "reboot" the immune system, which is maladjusted in MS and attacks the nervous system, impairing movement and balance.

Patients were randomly assigned to either the treatment or control group, something that hasn't been done in previous trials of stem cell therapy for MS, according to an accompanying editorial in Neurology.

Randomizing patient assignment gives the results more value, said UC San Diego stem cell researcher Larry Goldstein and neurologist Dr. Jody Corey-Bloom.

"It's a very exciting advance," Goldstein said. "It's a small study, but it sure looks like it was well controlled and carefully done."

Goldstein and Corey-Bloom, and the study authors themselves, cautioned that because the trial was so small, results must be regarded as preliminary. No improvement in disability was found in the trial, although there were so few patients that even a strong benefit might not have been noticed. The Phase 3 trial, which will include more patients, will be designed to find that benefit, if it exists.

In the Phase 2 trial, nine patients received immune suppression followed by stem cell transplants. Immune suppression alone was administered to a control group of 12 patients, for a total of 21 patients. The patients receiving stem cells were given their own, or autologous, hematopoietic stem cells, reducing the risk of rejection.

Multiple sclerosis comes in several different forms, none curable with existing treatments. The aberrant immune system attacks the protective myelin sheath around the axons of nerve cells, causing them to malfunction in transmitting signals. Certain drugs modify the immune system to reduce inflammation, providing temporary relief in some cases.

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Stem cells reduce MS brain damage