The immune system is essential for life and defends the body from invaders. MS symptoms are the result of disordered immune cells attacking the brain or the spine. Therefore, most MS drugs modify or suppress the destructive immune system.
A more aggressive option for people who do not respond to available treatments is to completely wipe out and then “reboot” the immune system.
Researchers have previously used powerful drugs to remove all the immune cells with varying outcomes. Since life without an immune system is not possible, a normal immune system should be restored after this treatment. This can be achieved by re-injecting the cells that can produce immune cells (such as bone marrow stem cells).
Canadian researchers have published long-term follow-up results from a group of 24 people with aggressive relapsing remitting MS who were treated using Autologous Haematopoietic Stem Cell Treatment (AHSCT) to reboot their immune systems. The individuals in this study presented with highly inflammatory MS with frequent relapses that did not respond to available disease modifying therapies.
The procedure used in this study involved the complete destruction of the immune system (known as immunoablation) using intensive chemotherapy with busulphan and cyclophosphamide. This was followed by reinfusion of the patients’ own immune stem cells (haematopoietic stem cells) that were collected prior to the chemotherapy.
The key outcome measure was the MS disease activity-free status (the absence of relapses, brain lesions or disability progression) over 3 years. Participants were also followed up over a longer period ranging from 4 to 13 years post-treatment. The procedure resulted in the complete elimination of relapses and no new brain lesions during the entire follow-up period for all of the 23 surviving participants.
One participant died of complications from liver failure as a result of the AHSCT procedure. Another participant required intensive care as a result of chemotherapy-related toxicity, but ultimately recovered. Some participants also experienced the expected post-transplant viral infections and subsequently recovered.
While the results are promising, there is still a long way to go before this approach can be used outside of clinical research trials. For example, this trial was a phase-2 trial, which means more studies with experimental controls are needed to prove safety and effectiveness of this treatment, and which subsets of patients might benefit from it most.
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