AHSCT or autologous haematopoietic stem cell transplantation, is a procedure where an individual’s blood and immune stem cells are extracted, prior to a high dose of chemotherapy which destroys the immune system, after which the bone marrow is returned to re-build the immune system.
This form of treatment has received much interest from the MS community and Australian doctors and researchers have also been closely following the development of evidence for its efficacy and safety.
A small US-based clinical trial of AHSCT for MS, called HALT-MS, recently published its findings after an average of five years follow-up of patients. This US-based study, led by Dr Richard Nash, had previously published 3-year follow-up results (see our article here).
The team used the BEAM form of chemotherapy to treat 24 patients with relapsing remitting MS, who had failed to respond to conventional therapies. The participants had a level of disability categorised as 3.0-5.5 on the 10-point Expanded Disability Status Scale (EDSS) used to measure disability levels in MS.
Of the 17 patients that were still in the trial at 5 years, 15 were given a classification of ‘event free survival’, defined as survival without disability progression, any new relapses, or new lesions detected by magnetic resonance imaging (MRI). Of these 17 patients, 91% had no progression, 86% had no clinical relapses and 86% had no MRI activity. The authors of the study noted that even those that did not remain ‘event free’ showed reduced relapse activity after the treatment compared to their relapse activity prior to the treatment.
On average the participants in the study also showed an improvement of 0.5 points on the EDSS scale – this is likely due the suppression of inflammatory activity allowing natural repair of myelin.
The treatment was not without side effects, with all patients requiring medical intervention for the dangerous reduction in blood cells following the chemotherapy. Other serious side effects including infections, respiratory problems, and cardiovascular complications. No mortality was directly attributed to the treatment, however three patients died during the 5 years following the treatment. These participants had all experienced worsening of their MS.
These results are consistent with some other contemporary trials which show approximately 60% of people with MS overall can remain disease activity free for up to 5-years following AHSCT treatment. Another major analysis just published by a collaboration of the Centre for International Blood and Marrow Transplant and the European Blood and Marrow Transplant Registry Autoimmune Working Party, showed 46% of people with MS remained free of disability progression at 5 years. However, within this group, 73% of people with relapsing MS were progression free compared with only 33% of people with progressive forms of MS.
The HALT-MS study shows that while there are risks involved with the use of AHSCT, people with highly active, treatment-resistant relapsing MS may benefit from this form of treatment. However, the authors of this study acknowledge that clinical trials directly comparing AHSCT with other treatments are needed to confirm this.
For further information on AHSCT as a treatment for MS, research underway in Australia, and the results of other international studies please visit our comprehensive AHSCT webpages here