MyelinWatch EL
← Studies & programmes
Myelin repairPhase 1 study evidenceCurrent status unknown

STEMS: neural precursor cell transplantation in progressive MS

Published by MyelinWatch:

Organisation
IRCCS San Raffaele Scientific Institute, Milan · Italy
Researcher
Maria A. Rocca and colleagues

STEMS (fetal neural precursor cells) · STEMS tested one injection into the spinal fluid of human fetal neural precursor cells in 12 people with progressive multiple sclerosis (MS). Researchers are exploring whether these cells could support nerve tissue and repair processes; the study was primarily designed to assess feasibility and safety.

What is the approach?

The cells were given once by lumbar puncture, with temporary immune suppression to reduce rejection. The proposed benefit is support for the nervous system and its own repair, not proven replacement of lost myelin in people.

Approach source: Stem Cell Research & Therapy — STEMS methods and rationale ↗

What is being studied

STEMS tested one injection into the spinal fluid of human fetal neural precursor cells in 12 people with progressive multiple sclerosis (MS). Researchers are exploring whether these cells could support nerve tissue and repair processes; the study was primarily designed to assess feasibility and safety.

Research stage

Phase 1 study evidence; current programme status is unknown

Current programme and human-study status are unknown.

What we know so far

The original open-label Phase 1 study treated 12 people. A July 2026 retrospective report describes 11 of them after a median 5.7 years. Serious adverse events occurred but were judged unlikely related to the transplant. Disability worsened: median EDSS rose from 7.25 before treatment to 7.75 at two years and 8.5 at long-term follow-up. Median score on the cognition test SDMT was 38 at baseline, 49 at two years and 42 at long-term follow-up. The long-term SDMT score did not differ statistically from baseline but was lower than at two years. A lower gray-matter atrophy rate than in the first two years is exploratory imaging evidence, not demonstrated clinical benefit or remyelination.

What this means for patients today

This is an experimental cell intervention, not an established treatment for MS. The small uncontrolled follow-up cannot show that transplantation slowed disability or restored myelin. The old Phase 1 registry is completed. In their July 2026 paper, the authors reported conducting a separate Phase 2 study, but its current enrolment and access have not been independently verified. No established approved treatment in clinical practice has been proven to reliably restore myelin in MS.

Treatment or approach
STEMS: fetal neural precursor cell transplantation in progressive multiple sclerosis
How it is intended to work
Intrathecal transplantation of human fetal neural precursor cells
Where the study is running
The NCT03269071 registry lists Italy; this publication does not establish Greek access
Source: Stem Cell Research & Therapy / Springer Nature — peer-reviewed research article ↗Source: ClinicalTrials.gov — STEMS Phase 1, NCT03269071 ↗ Source: Nature Medicine — original STEMS Phase 1 report ↗
Published by MyelinWatch
Last substantive MyelinWatch update

Programme updates — newest research developments first

  1. Retrospective follow-up of an open-label Phase 1 studyResearch event/source date:

    STEMS: long-term outcomes in 11 neural cell transplant recipients

    A retrospective STEMS report published on 22 July 2026 follows 11 of the 12 original NCT03269071 recipients for a median 5.7 years after one injection of human fetal neural precursor cells into spinal fluid. Serious adverse events occurred but were judged unlikely related to the transplant. Median disability score EDSS rose from 7.25 before transplantation to 7.75 at two years and 8.5 at long-term follow-up. Median score on the cognition test SDMT was 38 at baseline, 49 at two years and 42 at long-term follow-up. Five of 11 had new or enlarged T2 MRI lesions without contrast enhancement.

    Source: Stem Cell Research & Therapy / Springer Nature — peer-reviewed research article ↗Source: ClinicalTrials.gov — original STEMS Phase 1 ↗ Source: Nature Medicine — original STEMS report ↗