It is a phase I/II clinical study to evaluate the safety, tolerability and preliminary efficacy of VUM02 Injection in patients with acute graft-versus-host disease (aGvHD) who have failed systemic steroid therapy. VUM02 Injection (human umbilical cord-derived mesenchymal stromal /stem cells, hUC-MSC) is an off-the-shelf allogeneic cell therapy product comprising culture-expanded mesenchymal stromal /stem cells derived from the human umbilical cord tissue. The product is cryopreserved with the cell concentration of 5 x 10\^6 cells/mL. Patients with grade II to IV aGvHD who have failed systemic steroid therapy (i.e. patients with steroid-refractory aGvHD (SR-aGvHD)), will be recruited into this study. This study consists of two phases, a dose-escalation phase (phase I) and a dose-expansion phase (phase II).
Subjects aged 14-70 years (inclusive), male or female;
a. Steroid resistance: Progression of aGvHD at Day 3 of first-line steroid therapy, or no improvement in aGvHD at Day 7, or incomplete remission of aGvHD at Day 14;
b. Steroid dependence: failure to taper first-line steroid therapy or reactivation of aGvHD during taper;
Investigator assessment: Expected survival ≥ 3 months;
Subjects with lung disease who, in the judgment of the investigator, are not appropriate to participate in the study;
Serum virological examination shows positive results for active hepatitis B (hepatitis B core antibody positive and HBV-DNA in peripheral blood higher than the upper limit of normal), hepatitis C (hepatitis C antibody positive and HCV-RNA higher than the upper limit of normal), Treponema pallidum (TP) antibody or human immunodeficiency virus (HIV) antibody;
Patients with severe hepatic veno-occlusive disease or sinus veno-occlusive syndrome;
Subjects who developed aGvHD after donor lymphocyte infusion therapy for recurrence of underlying hematologic malignancies;