A new study suggests stem cell therapy can slow or stop progression of multiple sclerosis for many years, and the treatment is most effective in people with MS who have 'active inflammation' in their brain and spinal cord. Researchers said the study is one of the largest to date looking at stem cell transplantation as a treatment for MS and the findings offer some encouraging insights.

In the study, led by Imperial College London, autologous hematopoietic stem cell transplantation prevented symptoms of severe disease from worsening for five years, in 46 percent of patients. The treatment was given to patients with advanced forms of the disease that had failed to respond to other medications. The study suggested some patients even saw a small improvement in their symptoms following the treatment.

Researchers found that in patients with relapsing MS, 73 percent experienced no worsening of their symptoms five years after the treatment. The majority of the patients in the study had a progressive form of MS. Among these patients, one in three experienced no worsening of symptoms five years after treatment.

Some patients saw a small improvement in their symptoms, though this improvement was larger in patients with relapsing MS, compared to patients with the progressive form. Patients with relapsing MS had an average improvement in their Expanded Disability Status Scale score of 0.76, one year after the treatment. Patients with progressive MS had only a marginal improvement of 0.14.

The one-off treatment aims to prevent the immune system from attacking the nerve cells. However, as the treatment involves aggressive chemotherapy, the researchers stress the procedure carries significant risk. Out of the 281 patients who received the treatment in the study, eight died in the 100 days following the treatment. Older patients, and those with the most severe forms of the disease, were found to have a higher risk of death.

The researchers said these findings suggest larger trials of this procedure are now needed. The study was published in the journal JAMA Neurology.