Three-year outcomes from an ongoing clinical trial suggest that high-dose immunosuppressive therapy followed by transplantation of a person’s own blood-forming stem cells may induce sustained remission in some people with relapsing-remitting multiple sclerosis (RRMS). RRMS is the most common form of MS, a progressive autoimmune disease in which the immune system attacks the brain and spinal cord. The trial is funded by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, and conducted by the NIAID-funded Immune Tolerance Network (ITN) .

Three years after the treatment, called high-dose immunosuppressive therapy and autologous hematopoietic cell transplant or HDIT/HCT, nearly 80 percent of trial participants had survived without experiencing an increase in disability, a relapse of MS symptoms or new brain lesions. Investigators observed few serious early complications or unexpected side effects, although many participants experienced expected side effects of high-dose immunosuppression, including infections and gastrointestinal problems. The three-year findings are published in the Dec. 29, 2014, online issue of JAMA Neurology.

??These promising results support the need for future studies to further evaluate the benefits and risks of HDIT/HCT and directly compare this treatment strategy to current MS therapies,?? said NIAID Director Anthony S. Fauci, M.D. ??If the findings from this study are confirmed, HDIT/HCT may become a potential therapeutic option for people with this often-debilitating disease, particularly those who have not been helped by standard treatments.??

Scientists estimate that MS affects more than 2.3 million people worldwide. Symptoms can vary widely and may include disturbances in speech, vision and movement. Most people with MS are diagnosed with RRMS, which is characterized by epochs of relapse or flare up of symptoms followed by epochs of recovery or remission. Over years, the disease can worsen and shift to a more progressive form.

In the study, researchers tested the effectiveness of HDIT/HCT in 25 volunteers with RRMS who had relapsed and experienced worsened neurological disability while taking standard medications. Doctors collected blood-forming stem cells from participants and then gave them high-dose chemotherapy to destroy their immune systems. The doctors returned the stem cells to the participants to rebuild and reset their immune systems.

??Notably, participants did not receive any MS drugs after transplant, yet most remained in remission after three years,?? said Daniel Rotrosen, M.D., director of NIAID??s Division of Allergy, Immunology and Transplantation. ??In contrast, other studies have shown that the best alternative MS treatments induce much shorter remissions and require long-term use of immunosuppressive drugs that can cause serious side effects.??

The study researchers plan to follow participants for a total of five years, recording all side effects associated with the treatment. Final results from this and similar studies promise to help inform the design of larger trials to further evaluate HDIT/HCT in people with MS.

The work was sponsored by NIAID, NIH, and conducted by the ITN (contract number N01 AI015416) and NIAID-funded statistical and clinical coordinating centers (contract numbers HHSN272200800029C and HHSN272200900057C). The ClinicalTrials.gov identifier for the study High-Dose Immunosuppression and Autologous Transplantation for Multiple Sclerosis (HALT-MS) is NCT00288626.