Hematopoietic stem cell transplantation for patients with acute lymphoblastic leukemia and Down syndrome

Background: Hematopoietic stem cell transplantation (HSCT) is one curable option for high-risk acute lymphoblastic leukemia (ALL); however, transplant-related toxicities might be severe in patients with Down syndrome and ALL (DS-ALL). Procedure: HSCTs performed in patients with DS-ALL were identified in the Japan Society for Hematopoietic Cell Transplantation registry. Results: In the registry data, 11 patients with DS-ALL were identified. The median age at HSCT was 9 years (range: 6-22 years). Six patients underwent HSCT at non-remission status. Allogeneic grafts were utilized in all patients, including eight patients who received HSCT from unrelated donors. Reduced intensity conditioning regimens were used in three patients. All patients achieved neutrophil engraftment by a median of day 18 (range: day 11-61). Ten patients experienced grade 3 or more infectious episodes. Six patients experienced complications of the respiratory system. The incidences of II-IV or III-IV acute GVHD were nine (81.8%) or seven patients (63.6%), respectively. Chronic GVHD was observed in five (55.6%) out of nine evaluable patients. Seven patients died at a median of 6 months (range: 0-24 months) after HSCT. Two-year relapse-free and overall survival were 33.3% (95% CI: 2.5-64.1%) or 37.5% (95% CI: 5.9-69.1%), respectively. The causes of death were relapse (n=2), infection (n=2), bleeding (n=1), thrombotic microangiopathy (n=1), and chronic GVHD (n=1). Conclusions: Therapy-related mortality accounted for five out of seven deceased patients in this case series. Attempts to reduce toxicities should be considered in HSCT for patients with DS-ALL. Pediatr Blood Cancer 2015;62:148-152.