New treatment may stop multiple sclerosis in its tracks – but not without risks
A new treatment involving the combination of stem cell transplantation and high-intensity chemotherapy may halt relapses in people with highly active multiple sclerosis (MS), according to the results of a phase 2 clinical trial - but the treatment carries substantial risks, warn doctors.
The findings, published in The Lancet, indicate that stem cell therapy – a procedure known as autologous haematopoietic stem cell transplantation (aHSCT) – used in combination with an intensive form of chemotherapy “fully halted clinical relapses” in 23 of 24 patients with MS.
Unfortunately, one of the patients died as a result of complications, said to be a result of the chemotherapy and a second patient required intensive care. All but one patient also suffered what is described as a “toxic response” to the intensive treatment. The 24 trial participants, aged between 18 and 50, were enrolled from three Canadian hospitals and all had been given a poor prognosis having previously undergone standard immunosuppressive therapy which had failed to bring their MS under control.
IMAGE CREDIT: Phil and Pam Gradwell, Flickr.
A similar aHSCT procedure - which involves the harvesting of stem cells from the bone marrow of the patient - is a method already in use at some specialist MS treatment centres. The harvested stem cells are reintroduced to the patient via the bloodstream after chemotherapy to suppress or reset their immune system. However, while this existing method may be effective, many patients are said to still go on to relapse.
The new treatment involves completely wiping out the immune system as opposed to suppressing it. Researcher Dr Harold Atkins, from The Ottawa Hospital and the University of Ottawa in Canada, explains that the treatment is “similar to that used in other trials, except our protocol uses stronger chemotherapy and removes immune cells from the stem cell graft product. The chemotherapy we use is very effective at crossing the blood-brain barrier and this could help eliminate the damaging immune cells from the central nervous system.”
Of the 23 surviving participants, none suffered a relapse in the follow-up period, which ranged from 4 to 13 years. Eight of the 23 participants reported a “sustained improvement” in their disability 7.5 years after the treatment and six patients were able to reduce or stop disability support and return to work or study three years after treatment.
One of the researchers, Dr Mark Freedman, says the results should be interpreted cautiously. He says: “The sample size of 24 patients is very small, and no control group was used for comparison with the treatment group. Larger clinical trials will be important to confirm these results.
Dr Freedman adds: “Since this is an aggressive treatment, the potential benefits should be weighed against the risks of serious complications associated with aHSCT, and this treatment should only be offered in specialist centres experienced both in multiple sclerosis treatment and stem cell therapy, or as part of a clinical trial. Future research will be directed at reducing the risks of this treatment as well as understanding which patients would best benefit from the treatment.”
Success should be balanced against risks
Professor John Snowden, who works on aHSCT at Sheffield Teaching Hospitals, says: “There are different ways to deliver aHSCT, which vary in intensity and how the stem cells are manipulated. We need to balance how successful a treatment can be with its risks. Whilst this study protocol was remarkable in achieving such profound and sustained responses in patients with aggressive MS, its toxicity appears greater than with some other aHSCT techniques.
More clinical trials are needed to determine the ‘sweet spot’ - where the aHSCT technique is able to achieve a long term response in the majority of patients with an acceptable safety profile.”
Dr Emma Gray, Head of Clinical Trials at the Multiple Sclerosis Society, says: “This type of stem cell transplantation is a rapidly evolving area of MS research that holds a lot of promise for people with certain types of MS.
“In this latest trial patients were monitored post- treatment for a longer period than previous studies, providing valuable information about the long-term safety and effectiveness of HSCT as well as who might benefit.
“This treatment does offer hope, but it’s also an aggressive procedure with substantial risks and requires specialist aftercare. If anyone is considering aHSCT we’d recommend they speak to their neurologist.”
What is multiple sclerosis?
MS is a currently incurable chronic inflammatory condition affecting the central nervous system, and is caused when a person’s immune system attacks the body, known as autoimmunity. The condition is progressive and symptoms usually worsen over time.
According to the Multiple Sclerosis Society, MS affects around 100,000 people in the UK and most are diagnosed between the ages of 20 and 40, however symptoms may appear at other ages and the condition is more common in women.
Diagnosis is said to be complex, since signs and symptoms may vary widely from person to person, but common physical symptoms are said to include:
- Vision problems
- Balance and mobility problems
- Bladder and bowel problems
- Stiffness and/or spasms
- Problems swallowing
Other commonly-reported symptoms include cognitive difficulties, such as memory and thinking problems. Some people may also experience emotional and mental health problems, however there is no definitive list of symptoms and diagnosis can only be made by a neurologist. For more information, visit the Multiple Sclerosis Society website.
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