NATIONAL HARBOR, MD. – .” But, he said, it remains unclear which patients should undergo the procedure.
An especially pressing question is “whether transplant is an alternative to our high-efficacy disease-modifying therapies” (DMTs) in some high-risk patients, Jeffrey A. Cohen, MD, director of experimental therapeutics at Cleveland Clinic’s Mellen Center, said in a presidential lecture at the annual meeting of the Consortium of Multiple Sclerosis Centers.
Dr. Jeffrey A. Cohen
A handful of ongoing randomized controlled trials will bring answers, he said.
Stem cell therapy exists because there are gaps in MS treatment, Dr. Cohen said. “We have now more than 20 medications. However, none of these therapies is completely effective in all patients. In particular, there are some patients with very active disease who continue to have relapses or new MRI lesion activity despite treatment with all of the available therapies.”
And in progressive MS, the efficacy of a couple of agents is modest and mainly for people with ongoing focal lesion activity, he said. “Finally, all of these currently available therapies are intended primarily to prevent the accumulation of damage, and none of them directly promotes repair. So despite our progress in the field, there still are a number of unmet needs.”
‘Rebooting’ the immune system
Several types of stem cell therapy exist, including remyelination and anti-inflammatory therapy, Dr. Cohen said. In his lecture, he focused on immunoablative or myeloablative therapy followed by autologous hematopoietic stem cell transplantation.
This “complicated, multistep procedure” involves first eliminating the immune system to get rid of pathogenic inflammatory cells. This “big component is actually the therapy for MS. It’s also the step that has the most potential complications,” he said.
According to Dr. Cohen, the next step has been described as “rebooting” the immune system.
Does this procedure help patients with MS? In relapsing MS, reports suggest there’s “almost complete abrogation of disease activity following transplant,” he said, “a benefit that’s lasted 5-10-15 years. In addition, there’s also a benefit on the accumulation of CNS damage as measured by whole brain atrophy.”
Recent data, he said, suggests that MS patients most likely to benefit are young, developed MS relatively recently, are still ambulatory, and have highly active MS despite treatment with first- and second-line agents.
However, there have only been two randomized controlled trials of stem cell transplantation versus DMT, and Dr. Cohen said both studies have limitations. The first one, from 2015, is very small, with just 21 subjects. The second study – from 2019 – is larger (n = 103), but some patients weren’t taking higher-efficacy DMTs.
Other research is more promising: Dr. Cohen highlighted a 2017 analysis that found patients with relapsing/remitting MS who underwent stem-cell transplantation were more likely to be symptom-free at 2 years (78%-83%) than those who took DMTs in clinical trials (13%-46%).