There are many types of stem cells that are undergoing research and which are producing knowledge about their potential use in treating MS. Many of these studies involve adult mesenchymal (pronounced messENkimmul) stem cells, which are present in many tissues of the body, including bone marrow and fat (adipose tissue). These cells are being tested for their ability both to treat immune disorders and promote tissue repair. Further study is necessary to determine what kind of cells might prove optimal for treating some or all people with MS.
Stem cell therapy, even in the controlled setting of a clinical trial, carries the possibility for substantial risks. Anyone who is considering enrolling in a clinical trial should evaluate carefully the potential adverse events that will be outlined in the “informed consent form” that trial participants must sign.
HSCT to Reboot the Immune System: One type of procedure that has been explored for several 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 is believed to launch 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 by chemotherapy or radiation or both. Then the stored stem cells are reintroduced usually by infusion into the vein. 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.
This approach is being investigated in Canada, the United States, Europe and elsewhere. For example:
• An international clinical trial of this procedure, being led by Dr. Richard Burt of Northwestern University in Chicago, is now recruiting individuals who have not responded to other disease-modifying therapies. THIS TRIAL IS CURRENTLY RECRUITING PARTICIPANTS at its sites at Northwestern University, Rush University Medical Center, University of Sao Paulo, Uppsala University and Sheffield Teaching Hospitals NHS Foundation Trust. Read more about who may be eligible to participate. Dr. Burt and colleagues recently published a case series exploring outcomes for individuals who underwent the procedure.
• A multi-center, 5-year trial called the HALT MS (High-Dose Immunosuppression and Autologous Transplantation for Multiple Sclerosis) Study is expected to be completed in 2015. It is testing HSCT in people with MS who have active disease that was not controlled by disease-modifying medications. The trial is funded by the National Institutes of Health and the Immune Tolerance Network. Interim results were recently reported suggesting that after three years, 78.4% of participants experienced no new disease activity. When this trial has completed its five-year duration, it will be an important addition to research needed to determine whether this approach to stem cell transplantation is safe and effective in people with MS. THIS TRIAL IS ONGOING AND NOT SEEKING ADDITIONAL PARTICIPANTS.
Adult Mesenchymal Stem Cells to Reduce Disease and Augment Repair: Another experimental approach being tested in clinical trials is similar to HSCT, except that the individual’s immune cells are not destroyed or replaced. An individual’s own mesenchymal stem cells are isolated from the bone marrow or blood stream and multiplied in the lab, and then re-introduced in greater numbers into their body. This approach is being tested in several clinical trials including:
• A small, open-label, phase I clinical trial at Cleveland Clinic tested the ability of an individual’s own mesenchymal stem cells to both inhibit immune mechanisms and to augment intrinsic tissue repair processes in people with relapsing forms of MS. They were given intravenously (infused into the vein). This study was led by Dr. Jeffrey A. Cohen and supported by the Congressionally Directed Medical Research Programs. The National MS Society provided support for a pilot study related to this trial to compare stem cells from people with MS and controls without MS, looking at how the cells survive and function, to enhance understanding from this stem cell trial. This trial, which was designed to evaluate safety and not designed to determine benefits, was completed and preliminary results were presented in September 2014, suggesting that this approach was safe and warrants a phase 2 trial, which is now in planning stages. THIS PLANNED TRIAL IS NOT YET RECRUITING ADDITIONAL PARTICIPANTS.
• A small, open label, phase I stem cell trial has begun at the Tisch MS Research Center of New York using individuals’own mesenchymal stem cells to derive more specific stem cells called “neural progenitor cells.” The cells are expanded in the laboratory and then injected into the space around the spinal cord (intrathecal). The goal is to inhibit immune mechanisms and to augment tissue repair. THIS TRIAL IS ONGOING AND NOT SEEKING ADDITIONAL PARTICIPANTS.
• A small, open label, phase I trial of stem cells derived from placenta (known as “PDA-001” manufactured by Celgene Cellular Therapeutics) was completed in 2014, and results suggested this approach was safe. The study involved 16 people with relapsing-remitting or secondary-progressive MS at sites in the U.S. and Canada. This study was designed to evaluate safety and not designed to show effectiveness. In the published paper, the researchers comment that the next step, a proof-of-concept clinical trial, is planned. THIS PLANNED NEXT TRIAL IS NOT YET RECRUITING PARTICIPANTS.
• A placebo-controlled, phase II stem cell trial involving people with secondary-progressive MS and primary progressive MS has begun at Frenchay Hospital in Bristol, United Kingdom, testing the benefits and safety of using individuals’ own bone marrow cells. The cells are extracted and then given by intravenous infusion immediately or one year after the extraction. The goal is to inhibit immune mechanisms and to augment tissue repair. THIS TRIAL IS RECRUITING PARTICIPANTS AT ONE SITE IN THE UNITED KINGDOM.
Larger, longer-term, controlled studies are needed to determine the safety and effectiveness of using stem cells to treat MS. When the results of these and subsequent clinical trials are available, it should be possible to determine what the optimal cells, delivery methods, safety and actual effectiveness of these current experimental therapies might be for different people with MS.
Read more about stem cell clinics.
Other Stem Cell Research: Another line of stem cell research in MS relates to efforts to repair nervous system damage directly with stem cells that may replace the cells that make myelin, the protective cover on nerve wires which is damaged during MS, and nerve cells that have been destroyed. One exciting avenue being explored in early stages is the concept of taking samples of a person’s skin cells and turning them into stem cells. These cells are called “induced pluripotent stem cells” or iPSC. The potential advantage of this approach is that it’s possible such cells would not be rejected by the person’s immune system, and this approach bypasses possible ethical concerns connected with human embryonic stem cells.
This research is still in its infancy as studies proceed to determine whether any types of stem cells can reverse MS damage and restore function. Read more about efforts to repair the nervous system.