Outcomes in Patients With Mixed Phenotype Acute Leukemia in Morocco

Abstract

Mixed phenotype acute leukemia (MPAL) includes biphenotypic and bilineal types of leukemia, which constitute rare subtypes that require individualized therapy. Outcomes in Moroccan patients with MPAL are unknown. Among 1264 patients with acute leukemia, 20 were classified as having MPAL, including 17 with biphenotypic acute leukemia (1.3%) and 3 with bilineal leukemia (0.2%). There were 8 adults and 12 children. In 12 cases (60%), leukemic blasts expressed myeloid and T-lymphoid antigens, and, in 5 cases (25%), leukemic blasts expressed B lymphoid antigens plus myeloid antigens. Patients were initially treated on protocols for acute myeloid leukemia (n=4), acute lymphoblastic leukemia (ALL, n=14), or with palliative care (n=2). The probability of survival at 2 years in MPAL cases was 52%± 14%. Six of the 12 patients younger than 15 years remain alive versus 1 of 8 adult patients. Patients treated with ALL-directed therapy had significantly higher overall survival than those treated with acute myeloid leukemia-directed therapy (P=0.003). There was no association between the phenotypic characteristics and the clinical outcome (P=0.83). In conclusion, MPAL represents 1.5% of acute leukemia in Morocco. The prognosis is poor, but initial treatment with therapy directed toward ALL, improved supportive care, and the prevention of abandonment of therapy may improve outcomes in this subgroup of patients.