Randomized placebo-controlled trial of CL2020, an allogenic muse cell-based product, in subacute ischemic stroke

J Cereb Blood Flow Metab. 2023 Dec;43(12):2029-2039. doi: 10.1177/0271678X231202594. Epub 2023 Sep 27.


Effective treatments for stroke after the acute phase remain elusive. Muse cells are endogenous, pluripotent, immune-privileged stem cells capable of selectively homing to damaged tissue after intravenous injection and replacing damaged/lost cells via differentiation. This randomized, double-blind, placebo-controlled trial enrolled ischemic stroke patients with modified Rankin Scale (mRS) ≥3. Randomized patients received a single intravenous injection of an allogenic Muse cell-based product, CL2020 (n = 25), or placebo (n = 10), without immunosuppressant, 14-28 days after stroke onset. Safety (primary endpoint: week 12) and efficacy (mRS, other stroke-specific measures) were assessed up to 52 weeks. Key efficacy endpoint was response rate (percentage of patients with mRS ≤2 at week 12). To week 12, 96% of patients in the CL2020 group experienced adverse events and 28% experienced adverse reactions (including one Grade 4 status epilepticus), compared with 100% and 10%, respectively, in the placebo group. Response rate was 40.0% (95% CI, 21.1-61.3) in the CL2020 group and 10.0% (0.3-44.5) in the placebo group; the lower CI in the CL2020 group exceeded the preset efficacy threshold (8.7% from registry data). This randomized placebo-controlled trial demonstrated CL2020 is a possible effective treatment for subacute ischemic stroke.Registry information: JAPIC Clinical Trials Information site (JapicCTI-184103, URL: https://www.clinicaltrials.jp/cti-user/trial/ShowDirect.jsp?japicId=JapicCTI-184103).

Keywords: Clinical trials; ischemic stroke; muse cells; regeneration therapy; stem cells.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Alprostadil / therapeutic use
  • Brain Ischemia* / drug therapy
  • Double-Blind Method
  • Humans
  • Ischemic Stroke*
  • Stroke* / drug therapy
  • Treatment Outcome


  • Alprostadil