Predictive factors for all-trans retinoic acid-related differentiation syndrome in patients with acute promyelocytic leukemia.

All-trans retinoic acid (ATRA) used for the treatment of APL can lead to the development of differentiation syndrome (DS), a potentially life threatening complication. Since ATRA is metabolized by cytochrome P450 (CYP) enzymes, we sought to identify drug interactions that might be associated with a higher risk for the development of DS in addition to other predictive factors related to the incidence of DS. We identified 60 consecutive patients with APL treated at our institution with ATRA from May 2004 until January 2010. Of the 60 patients identified, 29 (48%) developed DS within a median of 5 days (range 1-31) of ATRA initiation. We did not find any difference in overall incidence of DS whether patients were on concurrent CYP 2C8, 2C9 or 3A4 inhibitors, inducers or substrates. In multivariable analysis, higher peripheral blood blast counts on admission (p=0.04) as well as higher body mass index (p=0.003) were associated with developing DS. Out of the 29 patients with DS, there were 4 early deaths of which 2 were attributed to DS compared to no early deaths in the patients who did not develop DS (p=0.05). Regarding disease-related outcomes, only CR rate was different between patients developing DS versus those who did not develop DS.