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The following is a summary of “Mesenchymal Stromal Cell Implants for Chronic Motor Deficits After Traumatic Brain Injury: Post Hoc Analysis of a Randomized Trial,” published in the September 2024 issue of Neurology by Okonkwo et al.
Traumatic brain injury (TBI) is frequently characterized by chronic motor deficits.
Researchers conducted a retrospective study to assess whether intracranial implantation of allogeneic modified mesenchymal stromal (SB623) cells could improve chronic motor deficits after TBI.
They conducted a post hoc analysis of the double-blind, randomized, surgical, sham-controlled Phase 2 STEMTRA trial (June 2016 to March 2019) with 48 weeks of follow-up. Participants with moderate-to-severe TBI, at least 12 months post-injury, and chronic motor deficits were randomized 1:1:1:1 to receive stereotactic surgical implantation of SB623 cells (2.5 × 106, 5.0 × 106, 10 × 106) or a sham procedure. The primary efficacy endpoint revealed a significantly greater change in Fugl-Meyer Motor Scale (FMMS) scores for the SB623 group compared to controls at 24 weeks.
The results showed 211 participants screened, 148 were excluded, and 63 were randomized, with 61 (97%; mean age 34 [SD, 12] years; 43 men [70.5%]) completing the trial. Single participants in the SB623 2.5 × 106 and 5.0 × 106 cell dose groups discontinued before surgery. Safety and efficacy (modified intent-to-treat) were evaluated in those who had surgery (N = 61; SB623 = 46, controls = 15). The primary efficacy endpoint (FMMS) was met (least squares mean [SE] SB623: +8.3 [1.4]; 95% CI 5.5–11.2 vs. control: +2.3 [2.5]; 95% CI −2.7 to 7.3; P=0.04), showing faster FMMS score improvement in SB623 groups compared to controls at 24 weeks, with sustained improvement at 48 weeks. At 48 weeks, SB623 groups improved more in function and activities of daily living (ADL), but not significantly compared to controls, AEs were similar between groups, with no deaths or withdrawals.
Investigators found that implanting SB623 cells helped people with TBI recover motor function and daily living skills.