Outcomes Following Intolerance to Tacrolimus/Sirolimus Graft-versus-Host Disease Prophylaxis for Allogeneic Hematopoietic Cell Transplantation

•Early intolerance to graft-versus-host disease prophylaxis with tacrolimus and sirolimus (TAC/SIR) is associated with poor survival.•Intolerance to TAC/SIR before day +30 results in worse outcomes than intolerance at days +30 to +100.•Alternate regimens to replace TAC/SIR after intolerance do not salvage outcomes.•Patients with a high Hematopoietic Cell Transplantation Comorbidity Index may be at elevated risk of TAC/SIR intolerance.•Patients receiving myeloablation with TAC/SIR are at elevated risk of veno-occlusive disease.