PEDIATRIC MIXED-PHENOTYPE ACUTE LEUKEMIA- AN INDIAN PERSPECTIVE

Background: Mixed-phenotype acute leukemia (MPAL) is a very rare heterogeneous group of acute leukemia in pediatric patients. MPAL has different cliinico pathological and genetic characteristics so diagnosis and treatment is challenging. Management is more complex in low– middle-income countries (LMICs). To Aim: describe diagnosis and treatment outcomes of MPAL patients in a developing country. We study 8 pedi Methods: atric patients newly diagnosed with MPAL from January 2005 until December 2015 retrospectively. Three pediatric pat Results: ients (37.5%) diagnosed T/Myeloid and Five (62.5%) B/Myeloid through immunophenotyping of Eight MPAL patients. There were seven male and one female. The average age was 9 years old (range= 4-13 years). We found KMT2A gene rearrangement in one patient, Philadelphia-positive chromosomes in one, and FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) in two patients. Eight patients (100%) received acute lymphoblastic leukemia (ALL) induction, and six patients (75%) achieved complete remission (CR) with no induction deaths and two of the eight patients with induction failure were switched to AML therapy. Two patients (25%) started therapy with acute myeloid leukemia (AML) induction and both (100%) achieved CR then received consolidation therapy after AML induction treatment. The 5-year event-free survival (EFS) and overall survival (OS) rates were 75% and 100%, while the cumulative incidence of relapse was found in one FLT3-ITD B/myeloid and one KMT2A rearranged gene T/myeloid (25%) with a median follow-up duration of 8 years and treated with hyper-CVAD regimen a combination of chemotherapy drugs including cyclophosphamide, vincristine, Adriamycin, and dexamethasone induction and achieved remission. Patients treated with ALL-directed therapy had a 5-year EFS rate of 67% and OS rate of 100%. FLT3- ITD mutation showed a signicantly lower 5-year EFS rate of 50%. 5 year EFS and OS of MPAL patients 60% and 100% respectively. ALL treatment for induction demonstrated higher remission rates in pediatric MPAL wit Conclusion: hout mortality. ALL-directed therapy for pediatric MPAL is very effective.