ALL-TRANS RETINOIC ACID IN THE TREATMENT OF ACUTE PROMYELOCYTIC LEUKEMIAS

Acute promyelocytic leukemia is a rare and severe leukemia, associated with a disseminated intravascular coagulation (DIC) and a specific t(15 ;17) translocation. All-trans retinoic acid, a vitamin A derivative, is able to induce complete remission via a differentiation effect in almost all cases of first attack (Chinese and French results) or in first relapse (French data). Proliferation is not stopped during the first weeks of treatment and hyperleucocytosis is a major adverse effect. This treatment is given orally, generally without any infusion or transfusion. Patients are treated as out-patients. DIC rapidly disappears, and normal cells progressively replace the abnormal maturing cells. All-trans retinoic acid induces differentiation of malignant cells. These cells are then engaged in maturation process leading to an apparent normal phenotype. This is the first model of differentiation therapy in malignancy with a high complete remission rate.