Haplo-Identical Transplant Using Post Transplant Cyclophosphamide in Children – Single Centre Experience from a Developing Country

Abstract

Introduction The access to hematopoietic stem cell transplant [HSCT] for children lacking a matched sibling donor has vastly improved with the introduction of haplo-identical transplant using post-transplant cyclophosphamide(PTCy). There is limited data on the use of PTCy and we present our experience with the use of HaploHSCT with PTCy in children. Patients and Methods Between 2010 and August 2018, 86 children (≤ 15 years) underwent 95 haplo-identical transplants using PTCy as the major graft versus host disease (GVHD) prophylaxis. Disease status at the time of HSCT was classified into Early, Intermediate and Late disease based on modified CIBMTR criteria to include immune deficiencies and bone marrow failure disorders. Data on HSCT and outcomes were collected from the institutional database and individual medical records. Results The median age of these children was 7 years (range: 9 months – 15) including 51 boys and 35 girls. Indications for HSCT included malignant diseases in 35 (AML, ALL) and non-malignant diseases in 51 (immune deficiency, inherited bone marrow failure disorders, aplastic anemia). Myeloablative conditioning was used in 51 transplants and non-myeloablative conditioning in 45. Disease status included Early disease (ED) in 10, Intermediate disease in 53 and Late disease in 32 transplants. 13 haplotransplants were performed as a second rescue transplant after failure of either a Haplo, MUD or sibling donor HSCT. Engraftment was seen in 82% with graft failure in 8% and early death in 10%. The median time to neutrophil engraftment was 18 days (range: 13 – 25). Acute GVHD (grade 2-4) was seen in 34% of evaluable patients while chronic GVHD was seen in 44% of evaluable patients. Infections were a major problem in the first 100 days of HSCT with viral infections (CMV, BK) occurring in 70% of transplants and bacterial infections in 42%. At a median follow up of 28 months, the overall survival is 52%. 44 children (52%) are alive and well. All children transplanted with early disease are alive while survival is 62% with intermediate disease and 25% with late disease. Conclusion Haplo-identical transplants using PTCy is feasible in children and associated with reasonable outcomes. Infections remain a major hurdle to improving overall survival. Disease status at HSCT has a major impact on outcomes.