Deferasirox: uncertain future following renal failure fatalities, agranulocytosis and other toxicities

Abstract

Cases of fatal, acute, irreversible renal failure and cytopenias, including agranulocytosis and thrombocytopenia, have been disclosed in a postmarketing report on deferasirox, a few months after the European Union authorities and about a year after the FDA proceeded to its accelerated approval. No details on the incidence rate or the cause of these toxicities have yet been reported. Other toxic side effects include skin, gastric, auditory and ocular abnormalities, and hepatitis. Regular serum creatinine, blood counts and other toxicity monitoring as well as withdrawal of deferasirox from the patients affected and those with serum ferritin < 0.5 mg/l was recommended. Toxicity, inability to clear cardiac iron and high cost (60 euros/g) question the future universal role of deferasirox, by comparison with the safety and efficacy records of deferiprone, deferoxamine and their combination in the treatment of transfusional iron overload. Also questioned are the procedures adopted by regulatory authorities and the marketing methods of pharmaceutical companies on orphan drugs, which are of no benefit to thalassaemia patients in developing countries.