Acute Promyelocytic Leukemia Asian Consortium study of arsenic trioxide in newly diagnosed patients: impact and outcome

The Acute Promyelocytic Leukemia (APL) Asian Consortium analyzed a contemporaneous cohort of newly diagnosed patients with APL treated with and without frontline arsenic trioxide (ATO) in 6 centers. The objectives were to define the impact of ATO on early deaths and relapses and its optimal positioning in the overall treatment strategy. In a 21.5-year period, 324 males and 323 females at a median age of 45.5 years (range, 18.1-91.8; low/intermediate risk, n = 448; high risk, n = 199) were treated. Regimens included frontline all-trans retinoic acid (ATRA)/chemotherapy and maintenance with/without ATO (n = 436), ATRA/IV-ATO/chemotherapy (ATRA/IV-ATO; n = 61), and ATRA/oral-ATO/ascorbic acid with ATO maintenance (oral-AAA; n = 150). The ATRA/chemotherapy group had significantly more frequent early deaths within 60 days (8.3% vs 3.3%; P = .05), inferior 60-day survival (91.7% vs 98.4%/96%; P < .001), inferior 5-year relapse-free survival (RFS; 76.9% vs 92.8%/97.8%; P < .001), and inferior 5-year overall survival (OS; 84.6% vs 91.4%/92.3%; P = .03) than ATO-containing groups (ATRA/IV-ATO and oral-AAA). The addition of oral-ATO maintenance partly mitigated the inferior 5-year RFS resulting from the omission of ATO during induction (ATRA/chemotherapy/non-ATO maintenance vs ATRA/chemotherapy/ATO maintenance vs ATRA/IV-ATO vs oral-AAA, 71.1% vs 87.9% vs 92.8% vs 97.8%; P < .001). The favorable survival impacts of ATO were observed in all risk groups. In conclusion, ATO decreased early deaths, improved 60-day survival, and resulted in significantly superior RFS and OS. This trial was registered at www.clinicaltrials.gov as #NCT04251754.