Effect of Aging on Deferasirox Therapy in Transfusion-dependent Patients. A Prospective-Retrospective, Cohort-study

Background: Iron-chelation therapy is life-saving in patients on a chronic transfusion regimen as it reduces organ damage related to iron deposition in the tissues. Deferasirox, an iron-chelator, is characterized by pharmacokinetics variability, and some patients may discontinue the treatment due to toxicities. Objective: Understanding whether deferasirox plasma levels are related to patients' specific characteristics could help to optimize DFX dosage. Methods: We analyzed deferasirox plasma concentration in 57 transfusion-dependent anemic patients using the HPLC method in this prospective-retrospective cohort study. All outpatients (3 to 98 years) were treated with deferasirox (film-coated tablet) for at least one year (median dose, 16.5 mg/Kg once a day). Deferasirox plasma concentration was normalized for dose/Kg (C/dose) and corrected with a linear regression model that relates C/dose and the time of blood sampling (Cref/dose). Results: No significant differences in Cref/dose were found between males and females, either between different types of hemoglobinopathies or depending on the presence of the UGT1A1*28 polymorphism. Cref/dose has a positive and significant correlation with age, creatinine, and direct bilirubin. Cref/dose, instead, has a negative and significant correlation with Liver Iron Concentration (LIC), ferritin, and eGFR. Cref/dose was significantly different between three age categories <18yrs, 18-50yrs, and >50yrs, with Cref/dose median values of 1.0, 1.2, and 1.5, respectively. Conclusion: The study evidenced that to ensure the efficacy of deferasirox in terms of control over LIC and, at the same time, a lesser influence on renal function, the dose of the drug to be administered to an elderly patient could be reduced.