ActiTrexx GmbH, in collaboration with University Medical Center Mainz and partners in Dresden, Münster, and Dortmund, has successfully conducted the first clinical trial using activated regulatory T cells (ATregs, Actileucel) – derived from white blood cells of healthy blood donors. This novel cell therapy aims to prevent the graft-versus-host disease (GvHD) following an allogeneic stem cell transplant. The Phase I/II study has yielded extremely encouraging results: ATregs can be produced within 24 hours and injected immediately afterward; administration is safe and well-tolerated by patients – a significant step toward a widely available cell therapy.