Evaluation of the efficacy of chelation therapy with deferoxamine in patients with thalassemia major

BACKGROUND: The current treatment of thalassaemia maior (TM) is based on a hypertransfusion regimen, with deferoxamine (DFO) chelation therapy to minimize the consequences of iron overload. To evaluate the long-term efficacy of chelation therapy, a group of 9 patients treated for a period of 9 years was studied. METHODS: The mean age of patients at the beginning of chelation therapy was 7 years. The age range at the moment of the study was 11 to 21 years. Pre-transfusion haemoglobin values were maintained above 10 gr/dl. DFO was administered by 10-hour sub-cutaneous infusion, 5 or 6 days a week at a dose of 40 mg/kg. Different iron overload parameters were considered, with special attention to cardiac function, growth and endocrinologic development. Signs of DFO toxicity were also studied. RESULTS: The final mean iron elimination rate was 72.6%. One patient died from cardiac haemosiderosis. Eight of the 9 patients showed significant growth impairment and 7, who have attained puberal or post-puberal age, suffer from one or more endocrinologic disorders (6 hypogonadism, 2 diabetes mellitus, 2 hypothyroidism and 1 hypoparathyroidism). The only toxic effect observed was transient crystalline opacity in 2 patients. CONCLUSIONS: Despite the early initiation of chelation therapy, TM patients receiving hypertransfusion regimen showed iron overload, with myocardiopathy, growth retardation and several endocrinologic disorders, mainly secondary hypogonadism, glucose metabolism disfunction and primary hypothyroidism.