Cyclophosphamide, Abatacept, and Tacrolimus for GvHD Prevention

Cyclophosphamide 50 mg/kg IV over 2 hours on Day +3 and +4 Abatacept 10 mg/kg IV on days +5, +14, and +28 Tacrolimus 0.02 mg/kg IV by continuous infusion, starting on day +5. May switch to oral when tolerated, adjusted to maintain a drug level between 5-12ng/mL. Treatment is discontinued on day +60 after a 4 week-taper