1. ¹Department of Pediatrics, M.D. Anderson Cancer Center Houston, TX, USA
2. ²Department of Radiation Oncology, M.D. Anderson Cancer Center Houston, TX, USA
3. ³Department of Blood and Marrow Transplantation, M.D. Anderson Cancer Center Houston, TX, USA

Correspondence: Dr KW Chan, Texas Transplant Institute, 8201 Ewing Halsell, Suite 280, San Antonio, TX 78229, USA. E-mail: kawah.chan@mhshealth.com

⁴Current address: Department of Pediatrics, University of Rochester Medical Center, 601 Elmwood Avenue, Box 777, Rochester, NY 14642, USA

⁵Current address: St Jude Children's Research Hospital, 332 N Lauderdale, Memphis, TN 38105, USA

⁶Current address: Texas Transplant Institute, 8201 Ewing Halsell, Suite 280, San Antonio, TX 78229, USA

Received 22 August 2005; Revised 1 November 2005; Accepted 2 November 2005; Published online 23 January 2006.

Abstract

We evaluated the efficacy and toxicity of adding 9 Gy of total body irradiation (TBI), in three single daily fractions of 3 Gy, to the reduced intensity regimen of fludarabine 30 mg/m² i.v. 4 days and melphalan 140 mg/m² i.v. 1 day in advanced pediatric hematologic malignancies. Twenty-two acute lymphoblastic leukemia (ALL), six acute myeloid leukemia (AML), and one non-Hodgkin lymphoma patients were transplanted. Of these, 13 were beyond second remission, and five had prior hematopoietic stem cell transplant (HSCT). Twenty-one donors were unrelated, of which 19 were from cord blood (CB) units. Three of the eight related donors were genotypically disparate. Oral mucositis and diarrhea were the most common toxicities. Twenty-seven patients achieved neutrophil engraftment (median 16 days), and 23 had platelet engraftment (median 42 days). One patient had primary graft failure. Seven patients died of non-relapse causes in the first 100 days. With a median follow-up of 52 months, seven of 22 ALL, five of six AML, and one of one lymphoma patients are alive and in remission. The regimen of TBI, fludarabine, and melphalan allows the engraftment of allogeneic hematopoietic stem cells (including mismatched CB). It was fairly well tolerated in pediatric patients, even for second transplants. Its efficacy requires further evaluation.