CPX-351 Induces Remission in Newly Diagnosed Pediatric Secondary Myeloid Malignancies.

Secondary myelodysplastic syndromes and acute myeloid leukemia (sMDS/AML) are rare in children/adolescents and have a dismal prognosis. The mainstay therapy is hematopoietic cell transplantation (HCT) but there has been no innovation in cytoreductive regimens. CPX-351, a fixed 5:1 molar ratio of liposomal cytarabine/daunorubicin, has shown favorable safety and efficacy in elderly individuals with sAML and children with relapsed de novo AML. We report the outcomes of seven young patients (six with newly diagnosed sMDS/AML and one with primary MDS/AML) uniformly treated with CPX-351. Five patients had previously received chemotherapy for osteosarcoma, Ewing sarcoma, neuroblastoma, or T-ALL; one had predisposing genomic instability disorder (Cornelia de Lange); and one MDS-related AML and multi-organ failure. The median age at diagnosis of myeloid malignancy was 17 (13-23) years. Patients received 1-3 cycles of CPX-351 (cytarabine 100mg/m2 plus daunorubicin 44mg/m2) on days 1, 3, and 5, resulting in complete morphologic remission without overt toxicity or treatment-related mortality. This approach allowed for adding FLT3 inhibitor as individualized therapy in one patient. Six patients were alive and leukemia-free at 0.5-3.3 years after HCT. One patient died from disease progression before HCT. Concluding, CPX-351 is an effective and well-tolerated regimen for cytoreduction in pediatric sMDS/AML warranting prospective studies.