Evaluation of the efficacy and safety of arsenic trioxide dosing in obese patients with acute promyelocytic leukemia.

Arsenic trioxide (ATO) is the backbone of acute promyelocytic leukemia (APL) treatment and is dosed based on weight with no upper limit, therefore obese patients receive large doses and may be vulnerable to adverse effects and dose holdings. Twenty-seven patients receiving ATO during induction were categorized as obese ( = 16) or non-obese ( = 11) based on body mass index (BMI) ≥30 kg/m in this retrospective study. Doses were held or modified due to composite adverse effects in 9 (56%) obese patients and 7 (64%) non-obese patients ( = 1.00). There were higher rates of dose holdings (13% versus 0%;  = .5) and dose modifications (13% versus 0%;  = .5) due to hepatotoxicity in obese versus non-obese patients. There were no differences in efficacy parameters. These data suggest that obese patients have similar overall incidence of adverse effects to ATO as non-obese patients; any difference in risk of hepatotoxicity will require clarification in a larger study.