Treosulfan Fludarabine and Low-Dose Total Body Irradiation for Children and Young Adults with Acute Myeloid Leukemia or Myelodysplastic Syndrome Undergoing Allogeneic Hematopoietic Cell Transplantation: A Prospective Phase II Trial of the Pediatric Blood and Marrow Transplant Consortium

摘要

This multicenter study evaluated a treosulfan-based regimen in children and young adults with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) undergoing allogeneic hematopoietic cell transplant (HCT). Forty patients with median age 11 years (1–19) underwent allogeneic HCT for AML in first (n=18), second (n=11), third or greater remission (n=3); or MDS (n=8) using bone marrow (n=25), peripheral blood stem cells (n=5) or cord blood (n=9). The regimen consisted of body surface area (BSA)-based treosulfan 10 g/m²/day (BSA ≤ 0.5 m²), 12 g/m²/day (BSA > 0.5 – 1.0 m²), or 14 g/m²/day (BSA >1.0 m²) on days −6 to −4; fludarabine 30 mg/m²/day on days −6 to −2; and a single fraction of 200 centigray total body irradiation on day - 1. Graft-versus-host disease (GVHD) prophylaxis included tacrolimus and methotrexate for marrow and peripheral blood stem cell and cyclosporine/mycophenolate mofetil for cord blood. One-year overall survival, disease-free survival, and non-relapse mortality were 80%, 73% and 3%, respectively. One-year relapse was 38% for AML and 13% for MDS. No serious organ toxicities were observed. All 37 evaluable patients engrafted. Cumulative incidences of grade II-IV acute and chronic GVHD were 22% and 40%. BSA-based treosulfan dosing resulted in predictable area under the curve and maximum concentration, which is required for dosing without measuring individual pharmacokinetic parameters. Observed differences in pharmacokinetics did not impact disease control or regimen toxicity. This BSA-based treosulfan regimen resulted in excellent engraftment and disease-free survival, minimal toxicity and transplant-related mortality (3%) in children and young adults with AML and MDS.