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CHARLOTTE, N.C. — Autologous hematopoietic stem cell transplant (aHSCT), pursued for decades as a potential cure for multiple sclerosis (MS), is associated in the modern era with a high potential for extended or permanent disease control and an acceptable risk profile, an update of recently reported experiences suggested.

In one center with 22 years of follow-up in more than 100 patients, none of those treated has needed a disease-modifying medication or has shown evidence of ongoing inflammation since the procedure, investigator Mark S. Freedman, MD, director of the Multiple Sclerosis Research Unit at the University of Ottawa in Ottawa, Ontario, Canada, said in a presentation on May 28 at the Consortium of Multiple Sclerosis Centers (CMSC) 2026 Annual Meeting.

While this type of success, drawn from data at his own center, has not been common, Freedman said that low rates of response have been reported from other sites as well. Enough that he no longer considers this therapy experimental. Rather, he said it is now a valid option in carefully selected patients.

A joint consensus statement issued 1 year ago by the European Committee for Treatment and Research of Multiple Sclerosis and the European Society for Blood and Marrow Transplantation (ECTRIMS/EBMT) takes a similar position.

“Consider aHSCT as an appropriate escalation therapy for people with highly active MS in whom high-efficacy disease-modifying therapy [DMT] has failed,” the statement said. “This indication should be adopted widely and with equitable access in all geographic areas.”

Promising Outcomes From Ottawa

The University of Ottawa program started in 2002, about 7 years after the first human trials with aHSCT in MS. As of January 2026, 131 patients with MS have undergone aHSCT. More than 40 others have been treated for other neurologic conditions such as myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, and stiff person syndrome.

Outcomes with the first 24 patients with MS were published in The Lancet in 2016 when the maximum follow-up duration was 13 years. At that time, MS activity-free survival was 69.6% at 3 years. There were no relapses, no new gadolinium-enhancing lesions, and no new T2 lesions detected on MRI.

Juxtaposing these results with those from four other centers that published data on similar numbers of patients, Freedman noted that relapse rates overall were low. However, his center — for reasons that Freedman said are still unclear — was the only one with zero relapses.

Updating outcomes through January of this year, Freedman said patients treated with aHSCT still report no new relapses, no therapeutic failures, and no current DMT use.

In this update, as in the 2016 report, a minority of patients have had disability progression. However, Freedman also noted that some patients have gained neurologic function since their procedure.

Improved Safety

Safety with aHSCT, which involves a complete reconstitution of the immune system, has improved over time, according to Freedman, with the only transplant-related death occurring before 2016.

He credited better protocols, including better conditioning regimens, with a major reduction in risk for complications.

However, there is no standard protocol for aHSCT and this includes the conditioning regimen, which plays the key role in immune reconstitution, Freedman said.

In his center, high-intensity myeloablation is used for conditioning. That differs from practice in most centers and from the approach highlighted in the ECTRIMS/EBMT consensus statement, which recommends lymphomyeloablative conditioning, which is considered intermediate intensity.

“This may or may not explain why we have had no relapses, but there are many other variables that might play a role,” Freedman told Medscape Medical News. “This is something that needs to be evaluated as we try to identify the most effective protocols.”

More Research Needed

Even though the ECTRIMS/EBMT consensus statement does not call for aHSCT to be performed within a clinical trial, it does indicate more research is needed.

In particular, the statement suggests that immune reconstitution should be tracked with multiple biomarkers to better understand the mechanisms of benefit and, by extension, to determine how protocols might be improved.

Even though aHSCT has never been compared to any DMT in a head-to-head trial, Freedman cited a 2023 pairwise comparison that looked at outcomes with aHSCT relative to fingolimod, natalizumab, and ocrelizumab.

That study concluded aHSCT is superior to fingolimod for the endpoints of relapse prevention and recovery from disability, but this superiority was called “marginal” relative to natalizumab, and follow-up was not sufficient to judge efficacy in relation to ocrelizumab.

The data regarding the use of aHSCT for control of progressive MS are far more limited, Freedman said. Overall, the signals from these studies have been mixed, suggesting that no strong conclusions can be drawn, he added.

Collaboration Is Key

In the 20-plus year experience, Freedman credited at least some of the success to the collaborative relationship between neurologists and hematologists at his institution. Important differences between aHSCT performed for MS relative to nonneurologic indications make that close working relationship essential, he said.

This point was reiterated by Paolo A. Muraro, MD, PhD, a professor of neurology, neuroimmunology, and immunology at the Imperial College London in London, England, who headed the writing committee for the ECTRIMS/EBMT consensus statement.

While “neurological expertise in selecting and managing appropriate candidates” is clear, “transplant experience specific to MS is crucially important for hematology services,” he told Medscape Medical News.

However, he expressed caution about the high-intensive conditioning used in Ottawa.

“While high-intensity conditioning can result in higher efficacy, the higher risk of toxicity requires even more specific expertise to ensure safety,” he said. In the consensus statement, intermediate-intensity conditioning is recommended “as the most road-tested and evidence-based compromise between efficacy and safety.”

Yet this could change as more information is gained about variables that affect outcomes. Reiterating the message from Freedman and the consensus statement, Muraro said, “More data should be collected to define the optimal treatment protocol.”

Freedman reported having financial relationships with Alexion Pharmaceuticals, AstraZeneca, Biogen, EMD Serono, Find Therapeutics, F. Hoffman-La Roche, Horizon, Novartis, Quanterix, Sanofi Genzyme, and Teva Canada Innovation. Muraro reported having financial relationships with Cellerys, Jasper Therapeutics, and Magenta.