Outcomes in Patients With Mixed Phenotype Acute Leukemia in Morocco

Summary: Mixed phenotype acute leukemia (MPAL) includesbiphenotypic and bilineal types of leukemia, which constitute raresubtypes that require individualized therapy. Outcomes inMoroccan patients with MPAL are unknown. Among 1264patients with acute leukemia, 20 were classified as having MPAL,including 17 with biphenotypic acute leukemia (1.3%) and 3 withbilineal leukemia (0.2%). There were 8 adults and 12 children.In 12cases (60%), leukemic blasts expressed myeloid and T-lymphoidantigens, and, in 5 cases (25%), leukemic blasts expressed B lym-phoid antigens plus myeloid antigens. Patients were initially treatedon protocols for acute myeloid leukemia (n=4), acute lympho-blastic leukemia (ALL, n=14), or with palliative care (n=2). Theprobability of survival at 2 years in MPAL cases was 52%±14%.Six of the 12 patients younger than 15 years remain alive versus 1 of8 adult patients. Patients treated with ALL-directed therapy hadsignificantly higher overall survival than those treated with acutemyeloid leukemia–directed therapy (P=0.003). There was noassociation between the phenotypic characteristics and the clinicaloutcome (P=0.83). In conclusion, MPAL represents 1.5% ofacute leukemia in Morocco. The prognosis is poor, but initialtreatment with therapy directed toward ALL, improved supportivecare, and the prevention of abandonment of therapy may improveoutcomes in this subgroup of patients.Key Words: mixed phenotype acute leukemia, immunophenotype,prognosis