Result of APL treatment associated with more experience of centers and more treatment as consolidation.

Abstract

7069 Background: The first line therapy strategy remains controversial in acute promyelocytic leukemia (APL) patients. Arsenic trioxide (AS2O3) approved in relapsed or resistance patients and recently studies reveals benefits of AS2O3in first line therapy. Regardless of these, important challenges are early mortality during remission induction and post treatment relapse. Methods: Between 2000 and 2012, patients suffered APL whose was new case and confirmed by t(15;17) translocation with RT-PCR, enrolled in study. Until 2007, patients received 28 days AS2O3(0.15 mg/kg iv) as induction and after 28 days rest, treatment continued for 2 courses of consolidation therapy with the same dose and after 2007, two additional consolidation courses, one and two year after start treatment, was added for prevent post treatment relapse. At beginning of 2nd and 3th consolidation, consider CSF cytology and RT-PCR for detection of APL cells and weekly CNS prophylaxis by MTX and cytarabine, IT chemotherapy start if needed. Patients received no other treatment. Results: Totally 271 patients enrolled in study. Ninety six patients received 3 dose and 175 patients received 5 dose of AS2O3. Fifty four (20%) patients died during remission induction before achieve remission. In recent years, early mortality rate reduced below 10% compared with more than 24% in the early years. With median follow-up of 30 months, 170 (78.4%) patients among 217 patients (whose survived after successful induction therapy) were alive (mortality rate: 21.6%) and 2.5-year overall survival and leukemia free survival was 85% and 73% respectively. The cumulative incidence of relapse in group which received three courses of AS2O3 and group which received five courses of AS2O3was 41.5% and 12.6%, respectively (95%CI: 2.5-9.6, P-value=0.0001). Conclusions: Currently according recent studies, AS2O3 has been considered as first line therapy in APL patients but either early mortality or post treatment relapse remain challengeable factors which affect treatment result. Expedite the referral of patients and improvement of emergencies care can reduce early mortality. The next step might be in order to achieve best treatment strategy for reduce post treatment relapse.