A Fludarabine Based Conditioning Regimen Associated with A Good Survival Following HLA Identical Sibling/Family Donor Transplants in Patients with Aplastic Anemia.
Authors: Chandy Mammen , George Biju , Mathews Vikram , Apte Shashikant , Nair Velu , Deotare Uday , Thiurgnanam Rajasekhar , Kelkar Anjali Jaydeep , Melinkeri Samir , Das Satyaranjan , Sharma Ajay , Viswabandhya Auro , Srivastava Alok 
Published: October 2019

Abstract
Abstract 1194
Poster Board I-216
Between January 2001 and June 2009, 120 patients with aplastic anemia underwent HLA identical sibling or family donor transplants using a combination of Fludarabine 150-180 mg/m2 over 5 days and Cyclophosphamide 120 mg/kg over 2 days as the conditioning regimen. Antithymocyte globulin (ATG) 10 mg/kg x 4 days in addition was used in 34 patients. Graft versus host disease (GVHD) prophylaxis consisted of Cyclosporine with low dose Methotrexate. Graft source included peripheral blood stem cells (PBSC) in 108 and G-CSF stimulated bone marrow in 12. Seventy patients (58.3%) were considered as high risk (presence of fever/infection at time of HSCT or >20 transfusions prior to HSCT or failed previous immunosuppressive therapy).
There were 79 males and 41 females with a median age of 22 years (range: 2 - 51) including 36 children (age <15 years). PBSC was used in 108 while BM was the graft source in 12. The median cell dose infused was 7.1 × 108 MNC/Kg for PBSC (range: 1.9 – 19.6) and 4.9 × 108 TNC/Kg for bone marrow (range: 2.1 to 9.9). One hundred and thirteen patients (94.1%) engrafted while 2 (1.6%) had primary graft failure and 5 expired within the first 2 weeks due to infection. The median time to neutrophil engraftment (ANC > 0.5 × 109/L) was 12 days (range: 7-19) while platelet engraftment (Platelet count > 20 × 109/L) occurred at a median of 13 days (range: 0 -30). Acute GVHD occurred in 38 patients (33.3%) with grade III-IV GVHD in 13.1%. Acute GVHD was not significantly lower in patients where ATG was used in conditioning (21.8% with ATG vs 38.2% without ATG; p = 0.129). Nine patients (7.5%) had veno-occlusive disease of the liver while 11 (9.1%) had hemorrhagic cystitis; all responded well to supportive therapy. Bacterial infections were documented in 28% of transplant recipients while fungal infections (both probable and definite) occurred in 23%. CMV reactivation was seen in <5%. Chronic GVHD occurred in 32.6% of evaluable transplant recipients and was limited in a majority of patients. At a median follow up of 30 months (range: 1 – 105), 88 patients (73.3%) are alive and well. Causes of death included sepsis in 19, acute GVHD in 7, chronic GVHD in 4, primary graft failure in 1 and road traffic accident in 1 patient. The overall survival was similar among children (75%) and adults (72.6%). The overall survival was significantly lower in the high risk group (60%) compared to the low risk group (92%; p = 0.0001).

Conclusion:
A combination of fludarabine and cyclophosphamide as conditioning for aplastic anemia is associated with good engraftment, a very low incidence of primary or secondary graft failure and good overall survival. Toxicity is low but acute and chronic GVHD remain significant problems. Sepsis continues to remain the major cause of death in these patients.

Disclosures:
No relevant conflicts of interest to declare.