Human umbilical cord mesenchymal stem cell transplantation for the treatment of acute-on-chronic liver failure: protocol for a multicentre random double-blind placebo-controlled trial.

introductionAcute-on-chronic liver failure (ACLF) is a prevalent and life-threatening liver disease with high short-term mortality. Although recent clinical trials on the use of mesenchymal stem cells (MSCs) for ACLF treatment have shown promising results, multicentre randomised controlled phase II clinical trials remain uncommon. The primary aim of this trial is to assess the safety and efficacy of different MSCs treatment courses for ACLF. METHODS AND ANALYSIS: This is a multicentre, double-blind, two-stage, randomised and placebo-controlled clinical trial. In the first stage, 150 patients with ACLF will be enrolled and randomly assigned to either a control group (50 cases) or an MSCs treatment group (100 cases). They will receive either a placebo or umbilical cord-derived MSCs (UC-MSCs) treatment three times (at weeks 0, 1 and 2). In the second stage, 28 days after the first UC-MSCs infusion, surviving patients in the MSCs treatment group will be further randomly divided into MSCs-short and MSCs-prolonged groups at a 1:1 ratio. They will receive two additional rounds of placebo or UC-MSCs treatment at weeks 4 and 5. The primary endpoints are the transplant-free survival rate and the incidence of treatment-related adverse events. Secondary endpoints include international normalised ratio, total bilirubin, serum albumin, blood urea nitrogen, model for end-stage liver disease score and Child-Turcotte-Pugh score. ETHICS AND DISSEMINATION: Ethical approval of this study has been obtained from the Fifth Medical Center of the Chinese PLA General Hospital (KY-2023-3-19-1). All results of the study will be submitted to international journals and international conferences for publication on completion of the study. TRIAL REGISTRATION NUMBER: NCT05985863.