Do all patients need cytotoxic drugs to obtain CR?
Whether all patients with APL require concomitant use of cytotoxic drugs is still controversial. Many patients with low initial leukocyte counts achieve CR with ATRA alone. For example, among 369 newly diagnosed patients with APL (median leukocyte counts, 2000/l) in the APL92 study of the Japan Adult Leukemia Study Group (JALSG), 223 patients (60%) received daily oral ATRA alone according to the study protocol which indicated to give ATRA 45 mg/m2 alone if patients’ initial leukocyte counts were <3000/l. According to this protocol, 126 patients (57%) continued ATRA alone and 119 (94%) of them obtained CR, and 97 patients (43%) received additional chemotherapy (daunorubicin+behenoyl cytarabine) at the time when their blasts and promyelocytes increased >1000/l and 85 (88%) of them achieved CR. Thus, 126 (34%) of 369 patients were able to achieve CR with ATRA alone, and these patients belonged to the good prognosis group for survival.9,15 Obviously potentially carcinogenic and organotoxic
