Update in Combined Chelation Therapy with Deferoxamine and Deferiprone in Brazilian Patients with Thalassemia Major: Assessment of Three Years

Introduction: Cardiac failure is a main cause of morbidity and mortality in patients with thalassemia major (TM) who are receiving regular blood transfusion due to iron overload. So, effective and adequate iron chelation is extremely important. Deferoxamine (DFO), the most widely used iron chelator, has poor compliance. Combined therapy with Deferiprone (DFP) increases chelation efficacy, decreases iron-induced complications, improves compliance increasing survival in thalassemia.

Objectives: Assessment of efficacy and safety in combined chelation with DFP and DFO in thalassemic patients with iron overload.

Methods and results: We have 50 thalassemia major patients in 4 Brazilian Centers (Boldrini Hospital, Sao Paulo Hematology Center, HEMEPAR and FAMEMA) receiving combined chelation therapy with follow up to three years. DFP (75–100 mg/kg/daily) and DFO (30–60 mg/kg, 4–7 days/week) are being administered during one to three years. Median age of this group is 21,5 y/o (range 8–35), with 48% female. Median age to start regular transfusions was 12 months (range 2–140) and to begin chelation therapy was 57 months (range 17–216). All patients were screened for Hepatitis C and 26% had positive sorology and/or PCR. Statistical analysis were made with Spearman test and Fisher test. All patients, except two, did cardiac and liver MRI in the initial phase of the study, resulting in 60,5% with cardiac iron overload (T2*<20ms), being severe in 31,2%. Assessment of liver iron concentration (LIC) showed 95,7% with liver iron overload (>3ug/g dry weight), being severe in 17,4%. During follow up, only 43 patients (86%) was screened with MRI. From these, 67,4% had cardiac iron overload (severe in 32,5%) and 78,6% had liver iron overload (severe in 11,9%). Mean serum ferritin before and after three years were 3095,7 ±1934,5 ng/ml and 2373,9±1987,6 ng/ml, respectively. Our data showed positive correlation between serum ferritin, LIC and ALT, even in initial data and after combined chelation therapy (p<0,001), but there is no correlation between cardiac T2* and LIC and between cardiac T2* and ferritin. DFP adverse events included 8% agranulocytosis, 22% neutropenia, 20% arthralgia and 38% gastric intolerance. DFO adverse events were 2,6% deafness, 2,0% cataract and 12% growth deficit. Hepatic toxicity was found in 6%, but without necessity to stop treatment. Compliance in this group was excellent in 48%, good in 22% and poor in 30%.

Conclusions: This is the first multicenter study to evaluate combined chelation therapy in Brazil based on cardiac MRI and LIC. Most patients had cardiac and hepatic iron overload probably because they began iron chelation lately, due to difficult access to iron chelators in the past. Cardiac iron overload didn’t have correlation with ferritin and LIC and these data need more understanding. Age of initial regular blood transfusion, increased transfusional requirement, inadequate chelation or delayed chelation may play a role in this question. Combined therapy with DFO and DFP is effective to decrease serum ferritin and LIC. Follow up and improving compliance may decrease cardiac iron overload. Adverse events are similar to literature. Combined therapy is safety in TM patients with transfusional iron overload.