POST-Transplant Cyclophosphamide (PTC) As Sole GRAFT Versus HOST Disease (GVHD) Prophylaxis in Patients Undergoing HLA Matched Sibling DONOR STEM CELL Transplant (SCT) for Severe Aplastic Anemia (SAA)

Between September 2010 and June 2012, 15 patients with SAA underwent HLA identical sibling donor SCT using Fludarabine 180 mg/m2 IV over 6 days and Cyclophosphamide 100 mg/kg IV over 2 days. Five patients had in addition a single fraction of Total Body irradiation (TBI) 200 cGy. Cyclophosphamide 50 mg/kg/day IV on day +3 and +4 was the sole GVHD prophylaxis. G-CSF mobilized peripheral blood stem cells (PBSC) was the graft source. Ten males and 5 females with a median age of 25 years (range: 8 – 42) had SCT. Median PBSC cell dose infused was 9.5 x 106 CD34/Kg (range: 5.4 – 17.2). Thirteen engrafted (86.6%) with median neutrophil and platelet engraftment of 15.4 days (range: 15-17) and 16.6 days (range: 12-32) respectively. Grade II–IV GVHD seen in 3 patients (23%) at 42, 49 and 68 days post SCT. Two responded to combination of cyclosporine and prednisolone while one patient with grade IV GVHD expired 64 days post SCT. Of 11 evaluable patients, 4 (36.3%) developed chronic GVHD which was limited in all. Two patients with de novo chronic GVHD were managed with prednisolone alone. Overall 7 patients (46.6%) have not required any immunosuppression after SCT while 3 have required immunosuppressive therapy for 114, 127 and 225 days respectively At a median follow up of 11 months (range: 1 – 22), 11 (73.3%) are alive and well including 7 patients who did not require any immunosuppressive therapy following SCT. The use of post transplant cyclophosphamide as GVHD prophylaxis following sibling donor transplant for SAA is associated with low rates of GVHD. A large number (46%) did not require any immunosuppression post SCT. Larger studies are required to understand the utility of this prophylaxis in sibling donor transplants for aplastic anemia