Reduction in the Incidence and Severity of Graft Versus Host Disease in HLA-Matched and Haploidentical Bone Marrow Transplantation Using Posttrasplant Cyclophosphamide. Experience of Two Latino-American Institutions

The Graft Versus Host Disease (GVHD) grades II-IV is present in up to 40% in Human Leucocyte Antigen (HLA) - identical related transplants and up to 80% of non-related. The HLA-haploidentical bone marrow transplantation (BMT) has been associated with significant risks of graft rejection and severe GVHD, as an excessive alloreactivity by host and donor T cells. High dose of Cyclofosfamide (Cy) after BMT inhibits both graft rejection and GVHD. We want to share our experience in preventing GVHD in HLA - haploidentical alloBMT and HLA-matched related BMT using the strategy of Cy post-Transplant. We evaluated 25 patients from March 2013 to June 2014, all of them were in advanced stages of the disease or they have characteristics of poor prognosis before transplantation. All patients received non-myeloablative conditioning and Cyclofosfamide (Cy) 50 mg/Kg postrasplant (on days 3 and 4 after transplantation), Mycophenolate mofetil (from day 5 to 35) and Tacrolimus (from day 5 to 180). The 64% (16) were male, mean age 30.6 years (range 2 – 67 years), with a average follow-up of 198 days (range 14-512 days). The 76% (19) were HLA-matched related alloBMT (7 patients) and HLA-haploidentical alloBMT (12 patients) in hematological malignancies, the rest of trasplants (24%) were HLA-haploidentical alloBMT in benign hematological diseases, overall survival (OS) at day 180 by type of transplant was 70%, 64%, and 67% respectively. 28% (7) had graft failure. 11 patients had no acute GVHD, 10 patients had GVHD grade I-II, and 3 patients had grade III, only 1 patient died because of grade IV (P = 0.005). Chronic GVHD occurred in 4 patients (16%). As a complication related to Cy therapy, hemorrhagic cystitis was observed 32%(8). Posttransplantation cyclophosphamide is able to reduce the likelihood of developing chronic GVHD and reduces the severity of acute GVHD, it plays an important role in the feasibility of a haploidentical transplant because the lower incidence of GVHD. Our results showed one of the most satisfactory and encouraging studies on the use of post-transplantation Cy performed in Latin America.