Researchers set out to assess the safety and effectiveness of autologous haematopoietic stem cell transplantation when used in routine healthcare rather than under clinical trial conditions. Their findings suggest that treatment with aHSCT for relapsing-remitting MS is linked to freedom from disease activity in a majority of patients, with acceptable adverse events.

Autologous haematopoietic stem cell transplantation, or aHSCT for short, is usually used to treat certain blood cancers, and involves harvesting stem cells from the person’s own bone marrow or blood followed by chemotherapy and antibody treatment. Emerging evidence indicates it is suitable for treating RRMS — characterized by distinct inflammatory episodes that cause varying degrees of residual disability. But aHSCT has yet to be included in most national clinical guidelines. 

Researchers in Sweden identified 231 patients with RRMS, 174 of whom had been treated with aHSCT before 2020: 2004 was when the first of these patients had been treated with aHSCT. Their average age when treated was 31, and 64 percent were women. How well aHSCT worked was evaluated by analysing data collected from the Swedish MS registry. Its safety was assessed by scrutinizing the patients’ electronic medical records for the 100 days following the procedure.

On average, patients had their disease for more than three years and received an average of two disease-modifying drugs before aHSCT; 23 had not had any treatment. 20 patients were started on a disease-modifying therapy after aHSCT. The average time to start an MS therapy after aHSCT was three years. After aHSCT, no evidence of disease activity in 73 percent of those treated after five years, and in 65 percent after 10 years. 

Among the 149 MS patients with some disability to begin with, 54 percent improved, 37 percent remained stable, and 9 percent got worse. The annualized relapse rate was 1.7 in the year before aHSCT and 0.035 during the monitoring period, which averaged 5.5 years. Or put another way, on average, a patient had 1.7 relapses in the year before aHSCT treatment, and one relapse every thirtieth year after aHSCT treatment.

Five patients had side effects from aHSCT requiring intensive care, and 61 developed a bacterial infection within 100 days of treatment. Febrile neutropenia (low white cell count accompanied by a high fever) was the most common side effect, affecting 68 percent of patients. Other viral infections were verified in 23 patients. Herpes zoster reactivation was documented in three, and three had a confirmed localized fungal infection. None died as a result of their treatment.

The researchers acknowledge this is an observational study, with no comparative group, which precludes definitive conclusions. The researchers also said their findings demonstrate that aHSCT for relapsing-remitting MS is feasible within regular healthcare and can be performed without compromising safety. 

The findings were published in the Journal of Neurology Neurosurgery and Psychiatry.