Tretinoin (All-trans retinoic acid : ATRA) is the drug of choice for the remission induction treatment of acute promyelocytic leukemia (APL). Its action against APL cells involves the degradation of promyelocytic leukemia-retinoic acid receptor α (PML-RARα) protein which represses their cellular differentiation.
We treated a 44-year-old Japanese male patient with APL using orally administered ATRA. He had previously undergone multiple resections of the bowels due to Crohn’s disease and his residual intestine length was only 120 cm. In order to investigate the pharmacokinetics of ATRA in this patient, we measured the plasma concentrations. On the 11th day of orally administering ATRA twice a day, the maximum concentration (Cmax) and the area under the plasma concentration versus time curve (AUC0-12) of ATRA were 51.9μg/L and 460μg·h/L, respectively. These data are comparable with those for patients without gastrointestinal complications, indicating that ATRA was sufficiently absorbed in spite of the patient having such a short intestine. Complete remission was achieved by the course of ATRA treatment.
