Stem cell therapy well tolerated in SPMS clinical trial

The treatment also may stabilize disability progression, study findings suggest

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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A novel therapy in which neural stem cells are injected into the brain was well tolerated by 15 people with secondary progressive multiple sclerosis (SPMS) in a pilot clinical trial.

Participants’ disability levels and cognition, as well as markers of inflammation and nerve damage, all remained stable for up to one year after the procedure.

“We desperately need to develop new treatments for secondary progressive MS, and I am cautiously very excited about our findings, which are a step towards developing a cell therapy for treating MS,” Stefano Pluchino, MD, PhD, a professor at the University of Cambridge who co-led the study, said in a press release.

“This is a really exciting study which builds on previous research funded by us,” Caitlin Astbury, research communications manager at the MS Society UK. “These results show that special stem cells injected into the brain were safe and well-tolerated by people with secondary progressive MS. They also suggest this treatment approach might even stabilise disability progression.”

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Results of the trial were published in Cell Stem Cell, in the paper “Phase I clinical trial of intracerebroventricular transplantation of allogeneic neural stem cells in people with progressive multiple sclerosis.”

Most people with multiple sclerosis (MS) will initially develop relapsing-remitting disease (RRMS), which is marked by flares where symptoms worsen, followed by periods of remission where symptoms ease. Over time, people with RRMS may develop SPMS, which is defined by symptoms that continuously worsen over time, regardless of relapse activity.

SPMS and other progressive types of MS historically have proven much harder to treat than relapsing forms of the disease. While several medications are approved for SPMS patients who still sometimes experience relapses, referred to as active SPMS, only one medication (mitoxantrone) is approved in the U.S. for SPMS patients who don’t experience relapses.

Neural stem cells, or NSCs, are specialized cells that are able to grow into neurons and other types of brain cells. In addition to their ability to make new brain cells, NSCs are known to secrete signaling molecules that have potent anti-inflammatory effects.

Secondary progressive MS patients injected with NSCs

Casa Sollievo della Sofferenza, a private research hospital in Italy, sponsored a small clinical trial, NSC-SPMS (NCT03282760), in which SPMS patients were given a single injection of NSCs into the brain, at doses from five to 24 million cells per injection. The study used NSCs derived from a single miscarried fetal donor.

“This is the first and largest clinical trial employing [human NSC-based cell therapy] from a homogeneous cell source in people with SPMS that aims to pave the way for the administration of the same standardized stem cell medicinal product in future clinical trials of efficacy,” the scientists wrote.

The study enrolled a total of 15 participants with with active or nonactive SPMS who’d been living with MS for 23 years on average, and had transitioned to SPMS about 10 years after the initial diagnosis. At the start of the study, all of the patients had fairly advanced disease and required a wheelchair to move around. After receiving the stem cell injection, all were followed for at least a year.

Along with the NSC injection, patients also were given a battery of steroids and other immune-suppressing treatments meant to prevent the body from rejecting the therapeutic cells.

The study’s main goal was to assess the safety of this stem cell therapy, and results were positive. No serious side effects or deaths related to the treatment were reported during the study. One participant experienced a mild seizure six months after the stem cell treatment. Researchers said that likely was a complication of the underlying MS, but they couldn’t rule out the possibility that it may have been related to the stem cell treatment.

A few of the patients experienced side effects that were related to the immune-suppressing meds given alongside the stem cells. Specifically, one experienced tremor, one had steroid-related psychosis, and three had minor infections. But all were managed by adjusting medications and/or giving appropriate supportive treatments.

Treatment approach safe, well tolerated, researchers say

Collectively these data “shows that the [NCS therapy injected into the brain] in people with active and non-active SPMS patients is safe and well tolerated and so is the proposed immunosuppressive treatment,” the researchers wrote.

Over the course of the year-long study, measures of functional disability and clinical disease progression were generally unchanged for the trial participants, with the exception of some minor changes in two individuals. One experienced an improvement and the other had worsening functionality.

Cognition scores and MRI assessments of disease activity also were essentially unchanged, and none of the patients experienced a relapse or flare during the study. Most of the markers of inflammation and nerve damage examined also were stable.

“Overall, this points to a substantial stability of the disease, without signs of progression,” the scientists wrote, though they cautioned that because the patients already had fairly advanced disability at the start of the study it may have been difficult to meaningfully measure worsening over the course of a year.

“We recognise that our study has limitations — it was only a small study and there may have been confounding effects from the immunosuppressant drugs, for example — but the fact that our treatment was safe and that its effects lasted over the 12 months of the trial means that we can proceed to the next stage of clinical trials,” Pluchino said.

“This was a very small, early-stage study and we need further clinical trials to find out if this treatment has a beneficial effect on the condition. But this is an encouraging step towards a new way of treating some people with MS,” Astbury said.