Repeated Intrathecal Mesenchymal Stem Cells for Amyotrophic Lateral Sclerosis

OBJECTIVE: To assess the safety and efficacy of 2 repeated intrathecal injections of autologous bone marrow–derived mesenchymal stem cells (BM‐MSCs) in amyotrophic lateral sclerosis (ALS). METHODS: In a phase 2 randomized controlled trial (NCT01363401), 64 participants with ALS were randomly assigned treatments (1:1) of riluzole alone (control group, n = 31) or combined with 2 BM‐MSC injections (MSC group, n = 33). Safety was assessed based on the occurrence of adverse events. The primary efficacy outcome was changes in Amyotrophic Lateral Sclerosis Functional Rating Scale–Revised (ALSFRS‐R) score from baseline to 4 and 6 months postinjection. Post hoc analysis includes investigation of cerebrospinal fluid biomarkers and long‐term survival analysis. RESULTS: Safety rating showed no groupwise difference with absence of serious treatment‐related adverse events. Mean changes in ALSFRS‐R scores from baseline to 4 and 6 months postinjection were reduced in the MSC group compared with the control group (4 months: 2.98, 95% confidence interval [CI] = 1.48–4.47, p < 0.001; 6 months: 3.38, 95% CI = 1.23–5.54, p = 0.003). The MSC group showed decreased proinflammatory and increased anti‐inflammatory cytokines. In good responders, transforming growth factor β1 significantly showed inverse correlation with monocyte chemoattractant protein‐1. There was no significant difference in long‐term survival between groups. INTERPRETATION: Repeated intrathecal injections of BM‐MSCs demonstrated a possible clinical benefit lasting at least 6 months, with safety, in ALS patients. A plausible action mechanism is that BM‐MSCs mediate switching from pro‐ to anti‐inflammatory conditions. A future randomized, double‐blind, large‐scale phase 3 clinical trial with additional BM‐MSC treatments is required to evaluate long‐term efficacy and safety. Ann Neurol 2018;84:361–373