Idarubicin-intensified haploidentical HSCT with GvHD prophylaxis of ATG and basiliximab provides comparable results to sibling donors in high-risk acute leukemia

We designed a novel haploidentical hematopoietic stem cell transplantation (haplo-HSCT) system using idarubicin (IDA) intensified conditioning regimens and combination of antithymocyte globulin and basiliximab for GvHD prophylaxis. The outcomes of 110 high-risk acute leukemia patients undergoing haplo-HSCT were compared with 69 contemporaneous high-risk patients receiving HLA-matched sibling transplantation using uniform IDA-intensified regimens. The relapse incidence of haplo-HSCT was 23.4%, and 3-year overall survival (OS) and disease-free survival (DFS) achieved 62.9%, 59.1%, respectively. The cumulative incidences of II-IV and III-IV aGvHD were 28.6 and 14.3%, while limited and extensive cGvHD were 19.4, 13.8%. All these results were equivalent to those of concurrent identical sibling transplantation. Three-year OS and DFS for patients in advance stage reached 48.5, 47.3%. Furthermore, the relapse, 3-year OS of positive minimal residual disease (MRD) patients did not differ from negative MRD patients (18.9% vs 11.5%, 63.6% vs 69.6%), indicating our intensified haplo-HSCT technique could circumvent the dismal prognosis of MRD. These data provide reinforcing evidence that our haplo-HSCT system could dramatically improve the survival of high-risk acute leukemia with low relapse and acceptable transplantation-related mortality, and might be a promising therapeutic option for high-risk patients.