The latest evidence on stem cell transplantation for multiple sclerosis

By Barbara Greenwood Dufour

In Canada, an estimated 90,000 people, or about one in 400, live with multiple sclerosis (MS). It’s the most common neurological disorder affecting younger adults, with people typically experiencing their first symptoms in their early 30s. Autologous hematopoietic stem cell transplantation (AHSCT) is an emerging treatment that could be an option for people with relapsing-remitting MS, the most common type of MS.

Relapsing-remitting MS is characterized by periods where symptoms get worse followed by periods of remission where some symptoms get better or remain the same. To treat relapsing-remitting MS, there are a number of disease-modifying therapies (DMTs) available. These therapies are used to reduce the frequency and intensity of relapses and delay the progression of disability. DMTs have been shown to be highly effective in the short term. But for most people, they cannot prevent the onset of progressive forms of MS, which have severe symptoms and limited treatment options. In addition, DMTs are associated with adverse effects and may not work for some individuals.


AHSCT could be an alternative to DMTs to treat aggressive or highly active relapsing-remitting MS when DMTs have had limited effect in controlling the disease. The AHSCT procedure aims to “reset” the immune system. It involves harvesting a person’s own stem cells, depleting their immune system using chemotherapy, then re-introducing the stem cells back into them. This reset can limit the progression of disability and reduce disease activity. Although AHSCT is an emerging health technology, the procedure has been performed for more than 25 years for MS, and it’s a well-established therapy for many blood cancers.

In the last 10 years, researchers in Canada have become internationally recognized for playing a key role in developing and refining AHSCT. The procedure is offered in Alberta and Ontario as an experimental treatment and is in limited use outside of research settings.

CADTH conducted a horizon scan of various health information sources to give health care decision-makers in Canada an early overview of this technology and the emerging evidence. CADTH is an independent agency that finds, assesses, and summarizes the research on drugs, medical devices, tests, and procedures.

The evidence on the clinical effectiveness of AHSCT suggests it might be an effective therapeutic option in people with relapsing-remitting MS who, despite being treated with DMTs, still show signs of high disease activity, such as frequent relapses and/or the development of brain lesions. Compared with DMTs, AHSCT might extend the period of progression-free survival (the length of time after a person starts treatment that their disease doesn’t get worse) and be more effective at slowing or halting disease activity. For some people, it could improve disability and symptoms. And since AHSCT is a one-time procedure, it could lead to cost savings when compared with the recurring costs associated with DMTs. However, more research is needed to compare AHSCT with newer DMTs and to monitor longer-term outcomes.

There’s some uncertainty about the safety of AHSCT. However, its safety profile has been improving over the last 25 years, as refinements to the treatment have reduced the risk of severe adverse events. Most safety concerns are largely similar to other stem cell transplant procedures.

It’s not known how many people with MS in Canada might want AHSCT — for example, we don’t know how many people are unsatisfied with their current DMT regimen and would be interested in considering AHSCT as a potential alternative. However, there are reports of individuals from Canada seeking AHSCT abroad.

If AHSCT were made broadly available in Canada, a limited number of people with MS would likely be eligible. Guidelines and recommendations generally suggest it can be offered to younger individuals with relapsing-remitting MS. For example, the Canadian MS working group on treatment optimization recommends that people between 18 and 31 years of age be considered for the procedure. This is because older people with MS typically have a higher level of disability and a higher risk of severe complications, which could reduce the likelihood of treatment success. Approximately 5,000 people living with MS in Canada are younger than 31 years of age.

Although emerging evidence shows that AHSCT likely improves outcomes compared with DMTs, AHSCT isn’t intended to replace DMTs altogether. Instead, it could be a potential alternative for people who are still early in their disease progression but show a high level of disease activity despite receiving DMTs. For these people, AHSCT may offer a new option for improving their MS symptoms and quality of life.

Around the world, AHSCT has been used to treat more than 1,500 people with MS. At least  three trials are currently in progress, and the results of these could provide a stronger evidence to inform decisions related to optimal AHSCT regimens and who should be eligible for the procedure.

The full report on AHSCT for the treatment of MS is freely available on the CADTH website at cadth.ca. To learn more about our Horizon Scanning program, visit cadth.ca/horizon-scanning, or to suggest a new or emerging health technology for CADTH to review, email us at HorizonScanning@cadth.ca. You can also follow us on Twitter @CADTH_ACMTS or speak to a Liaison Officer in your region: cadth.ca/contact-us/liaison-officers.

 

Barbara Greenwood Dufour is a knowledge mobilization officer at CADTH.