Results have been published from a series of individuals with multiple sclerosis who were treated experimentally with immune-suppressing therapy followed by transplantation of blood stem cells. This procedure aims at “rebooting” the immune system to prevent MS immune attacks against the brain and spinal cord. The authors report significant improvements in disability scores and reduced disease activity in a proportion of those with relapsing MS with disease durations of ten or fewer years, but not in those with secondary-progressive MS or in those with greater disease duration. Controlled clinical trials are needed to determine the full prospective benefits and risks of this treatment approach for people with MS, which is reported by Richard K. Burt, MD(Northwestern University) and colleagues report in JAMA (Published online January 20, 2015). This study was supported by foundations and private donors.
Background: One type of procedure that has been explored for many years in MS is called “autologous hematopoietic (blood cell-producing) stem cell transplantation” – or HSCT. This procedure has been used in attempts to “reboot” the immune system, which launches attacks on the brain and spinal cord in people with MS.
In HSCT, these stem cells (derived from a person’s own bone marrow or blood) are stored, and the rest of the individual’s immune cells are depleted or reduced, usually by chemotherapy. Then the stored stem cells are reintroduced back to the individual’s bloodstream. The new stem cells migrate to the bone marrow and over time produce new cells. Eventually they repopulate the body with immune cells. The goal of this currently experimental procedure is that the new immune cells will no longer attack myelin or other brain tissue, providing the person, what is hoped to be, a completely new immune system.
The Case Series: This publication reports on cumulative outcomes for individuals treated at Northwestern University. This was not designed as a clinical trial, so individuals were not randomized to their treatment group, and there was no comparator group or “blinding” of participants or their physicians, which are techniques typically employed to compare outcomes and avoid bias.
Over the course of about 10 years, 123 people with relapsing-remitting MS and 28 with secondary-progressive MS received the treatment, called “nonmyeloblative hematopoietic stem cell transplantation.” Nonmyeloblative means that the immune system was suppressed but not completely depleted. The treatment involved a hospital stay of about 10 days. The treatment was evaluated for safety and individual outcomes were tracked, including changes in disability score (EDSS), relapses, and MRI-detected disease activity.
Results: Results on 145 individuals available for follow-up were included in the analysis. Individuals were followed from 6 months to 5 years, or an average of 2.5 years. The investigators reported that EDSS scores improved, compared to pretreatment, by one point or more in 50% (41 out of 82 people) at year 2 and in 64% (23 out of 36 people) at year 4. Relapses and MRI-detected disease activity were also significantly reduced. In evaluating which type of individuals benefited from the therapy, the authors suggested that people with relapsing-remitting MS who had had MS for ten years or less showed improvements in their disability scores after transplantation. People with secondary-progressive MS or disease duration greater than ten years did not show improvements on their disability scores.
Safety: The investigators reported no treatment-related deaths and no serious infections. ITP (immune-mediated thrombocytopenia), a potentially serious bleeding disorder, developed in 7 people, and thyroid disorders developed in 7 people. Both disorders have been associated with the immune-suppressing treatments given prior to stem cell transplantation (alemtuzumab and antithymocyte globulin).
Comment: In an editorial published along with this paper, Stephen Hauser, MD (University of California, San Francisco) noted that uncontrolled case series such as this one have built-in limitations that can make it difficult to interpret the results. Dr. Burt and colleagues are currently conducting a clinical trial of this procedure.
Bruce Bebo, PhD, Executive Vice President of Research at the National MS Society, commented, “Because MS is a chronic disease, we look forward to seeing the results of longer-term follow up so that prospective benefits and the risks of this approach can be more fully characterized and understood. In addition, well-controlled clinical trials will need to be performed before we can know the full potential of this promising stem cell approach to MS treatment.”
With the urgent need for more effective treatments for MS, particularly for those with more progressive forms of the disease, the National MS Society believes that the potential of all types of cell therapies must be explored. The Society is currently supporting 15 research projects exploring various types of stem cells, including cells derived from bone marrow, fat and skin, and has supported 70 stem cell studies over the past 10 years.
Read more about stem cells and MS
Read more about available therapies for MS
Read an interview with Dr. Richard Burt