A clinical trial conducted in the USA, known as HALT-MS, has published interim results for an ongoing study of autologous haematopoietic stem cell transplant (AHSCT) for relapsing forms of MS.
The interim results from HALT-MS show that the majority of the 24 patients treated achieved remission from MS disease activity for up to three years. Overall, the disability level for the participants improved by 0.5 points on the EDSS scale at 3 years and measures of cognition and quality of life also showed some improvements.
The results were published in the journal JAMA Neurology in December. All patients enrolled in the study had relapsing forms of MS, with an average age of 37.7 years, an average EDSS score of 4.4, and disease duration of 12 years or less (average 5.7 years). The majority had failed to respond to two or more MS medications.
The results for this group of patients are consistent with other international studies suggesting that younger people with active MS, who have failed to respond to currently available therapies, may benefit from this aggressive form of treatment. People with progressive disease have shown much less favourable responses to the treatment. The results are also consistent with the current MS Research Australia Position Statement on AHSCT for MS – For the Statement and a full review of published international literature on AHSCT for MS, prepared by MS Research Australia, please click here.
While the full five-year follow-up results are yet to be completed and published, the data so far does suggest that the treatment’s effects may not be sustained over time. Relapses, MRI lesion activity and disability progression were absent in 82.8% of participants at 2 years following treatment and 78.4% of the 24 participants at 3 years. But in the subset of those that had reached the four year time point only 68.6% of patients remained in the ‘event free survival’ category. The authors conclude that longer term follow-up is required to establish the true durability of the response.
In this study, there were no deaths in the immediate period following chemotherapy and transplantation, although two patients died at 2.5 and 3.5 years following transplant, of severe worsening of MS and from worsening of pre-existing asthma, respectively. Adverse events occurred in all of the patients with the majority being related to low blood cell counts, infections and gastrointestinal effects as expected following this type of aggressive chemotherapy treatment.
The risk of death associated with AHSCT for MS remains relatively high, however, rates have been dropping over the years, with most experts agreeing that this is the result of careful selection of patients and provision of the treatment at highly experienced centres.
In an accompanying editorial in the same issue of JAMA Neurology, Assistant Professor Soldan from the University of Utah and Professor Weinshenker, from the Mayo Clinic, agree that this study shows that high dose immunosuppressive therapy may substantially suppress inflammatory disease activity in people with active MS in the short term. However, they also discuss that for such “an aggressive and expensive therapy” the certainty of the outcomes and long term sustainability of the effects of the treatment have yet to be demonstrated for AHSCT for MS.
For further information and for the MS Research Australia position statement on AHSCT for MS please click here.