What is the best management for hyperleukocytosis, the APL differentiation syndrome, and prolonged QT interval associated with ATO?
According to the experience in patients with APL in relapse, ATO induces complete hematologic and morphologic remission in approximately 85% of patients.44,45 Approximately 50% of patients with APL in relapse achieve a molecular remission after one 25-day course of ATO. Therefore, it is conceivable that ATO can be used as an alternative in patients in whom conventional treatment with ATRA plus chemotherapy is contraindicated. ATO is administered as a single agent and is quite well tolerated. Hyperleukocytosis, similar to that observed in patients receiving ATRA, occurs, and, in general, ATO may be continued with careful observation.46 Approximately 50% of patients develop leukocytosis with ATO with a peak WBC count at approximately 20 days after the first dose. Such leukocytosis resolves at a median of 10.5 days after the peak, despite continuation of ATO. With the development of the cardiorespiratory distress syndrome, the APL differentiation syndrome, in approximately 30%, dexamethas
