Randomized Pilot Study of Ruxolitinib for Switch-Maintenance Prophylaxis of Graft-versus-Host Disease in Allogeneic Hematopoietic Cell Transplantation After Intermediate-Dose Post-Transplant Cyclophosphamide (Rux Switch-Maintenance in Intermediate PTCY: RuSMa-PTCY) in Comparison to Full-Dose PTCY | Arctuva