New Findings on Stem Cell Transplantation, including HSCT, in MS

Transplantation of stem cells is a promising area of research that could lead to strategies that stop or even reverse damage caused by MS. Advances in this approach were presented during the ECTRIMS meeting in Barcelona this week. Stem cells can be found in many parts of the body and they have the remarkable potential to develop into many different cell types that have the potential to regenerate damaged tissue. This ability offers a new approach for treating diseases, including MS. In this update, I will be talking about two promising approaches: hematopoietic stem cell transplantation, and mesenchymal stem cell transplantation.

Hematopoietic Stem Cell Transplantation (HSCT)

HSCT is a procedure that involves transplanting of a person’s own stem cells derived from bone marrow after their immune system has been depleted, in an attempt to regenerate and “reboot” the immune system to stop MS attacks. This week an international consortium – that included 28 scientists from 10 different countries – presented their observations of outcomes of HSCT transplants involving 281 people who were followed anywhere from 2 months to 16 years after undergoing the procedure.

Most (78%) of the people they evaluated had progressive forms of MS, and their disability status measured by the EDSS scale ranged from very mild to very severe (1.5 to 9). The key outcomes the researchers focused on were progression-free survival and overall survival 5 years after the transplant procedure.

They found that the chances that participants were free of progression after 5 years were about 50-50. They also found that the probability of survival after 5 years was 93%, which are much better odds! So who did better, and who did worse? When they looked at the group who continued to experience progression after the procedure, they tended to be over age 37, had progressive MS, and had tried more than 2 disease-modifying therapies before getting the transplant. The researchers also looked at improvements that occurred during the year following the transplant, which were notable in 52% of those with relapsing MS and 31% of those with progressive MS.

These findings underscore for me the dilemma about HSCT, and why it needs more evaluation through additional clinical trials that are now underway. Those who did better were younger people with active, relapsing MS who haven’t tried as many approved therapies. These are the individuals for whom there are other less invasive therapies that might work well. Stem cell therapy, even in the controlled setting of a clinical trial, carries the possibility for substantial risks, and many doctors are uncomfortable recommending this procedure to people who may have other treatment options.  We need to fully understand the risks and benefits of this before a conclusion can be reached about this approach.  The ongoing clinical trials of HSCT will hopefully provide this for us in the near future. (Abstract 193)

MSC’s can be found in most tissues in the body, but the bone marrow, umbilical cord and adipose (fat) tissue are good sources for these cells. MSC’s have tremendous promise to help us understand and treat a range of diseases, including MS, but very few MSC-based treatments have been proven safe and effective so far - despite claims to the contrary.

One roadblock to establishing the clinical usefulness of MSC’s is that different teams use different treatment protocols, so it’s difficult to compare the outcomes of results. That’s why I was also encouraged to learn about a unique collaborative trial that’s getting underway in 8 countries that involves infusing MSC’s without depleting the immune system. The idea is to improve the body’s ability to repair damage to nervous system tissues. This “MESEMS” trial involves a network of independent trials, all following the same protocol and sending their data and MRI scans to centralized locations for combined analysis. This way they can increase the number of participants overall and get more powerful results.

They are planning to enroll about 160 people across Europe and Canada, and they will be recruiting participants with relapsing-remitting, secondary progressive or primary progressive MS as long as they show signs of active disease or inflammation. The researchers will be looking at safety, and also impacts on MRI and disease activity. If this strategy proves to be safe and effective, it will probably lead to a larger phase III trial. This novel approach is exciting, and an important step towards determining the full potential of these cells for the treatment of MS. (Abstract P1087)

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Bruce Bebo, PhD

Bruce Bebo, PhD, is Executive Vice President, Research at the National MS Society, and was previously a research immunologist focusing on the influence of sex hormones on MS. He is a driven and passionate Society volunteer, successful fundraiser and advocate, fueled in part by the fact that his mother had MS.