Tolerability and efficacy of deferasirox in patients with transfusional iron overload: results from a German 2-year non-interventional study.

Abstract

Iron overload (IOL) due to repetitive transfusions of packed red blood cells (pRBC) has a major impact on morbidity and mortality in patients with inherited bone marrow failure syndromes and hemoglobinopathies such as thalassemia and sickle cell disease. However, whether IOL influences the outcome of elderly patients with myeloid malignancies is not yet clear. Moreover, clinical trials have reported high drop-out rates during treatment with the oral iron chelator deferasirox (DFX). Here we report the results of a 2-year prospective observational study that aimed at describing the routine use of DFX in patients with hematological malignancies with regard to safety, efficacy and handling of the drug in a routine setting. A total of 406 patients were included. 58% of the patients were male. Most of the patients had myelodysplastic syndromes (MDS) (68%) and myeloproliferative neoplasms (MPN) (14%). Median time from first transfusion to study enrollment was 1.1 years (0-25.5 years) and most patients were chelation naive (91%) at enrollment. With regard to transfusion burden, most of the patients were moderately or mildly transfusion-dependent with 53% receiving 2-4 and 27% receiving less than 2 units of pRBC per month. Serum ferritin decreased from a mean of 2305 μg/l (± 1449 μg/l) to a mean of 1910 μg/l (± 1529 μg/l) at 24 months. There was no substantial change in transfusion-dependence during the observation period. Dose adjustments were reported in 48% of the patients with dose-escalation strategies being the most frequent reason for dosage increases (49%). The median observation time was 355days (5-1080days). Median duration of exposure to DFX was 322days (2-1078days). Two-hundred and ninety (72%) patients discontinued the trial prematurely after a median time of 235days (1-808days). Death (29%) and adverse events (23%) were the main reasons for discontinuation. Eleven percent of the patients discontinued treatment due to sufficient decrease in serum ferritin. Most frequent adverse events were decrease in creatinine clearance (22%), increase in serum creatinine (18%) and diarrhea (16%). This descriptive trial confirms the efficacy of DFX in decreasing the serum ferritin. Moreover, the high drop-out rates seen in prospective trials are recapitulated in this study, which can be attributed to adverse events in a substantial proportion of patients.