Reachthem: Baseline Characteristics of a 3 Year Prospective Registry of Children with Hemoglobinopathies Receiving Oral Iron Chelators in the Treatment of Transfusional Iron Overload

Management of hemoglobinopathies, mainly beta-thalassemia major, is well studied at controlled clinical trials. However, one should keep in mind that real life experience of pediatric patients with thalassemia major show remarkable differences across geographies and social-economic status. The effect of iron overload (IO) and outcome of chelation therapy also vary widely in this population. Chelators differ in side-effect profile, tolerability and ease of adherence, and (to some degree) efficacy for any specific patient.

The aim of the present study was to determine the characteristics of children with hemoglobinopathies receiving oral iron chelators (OICs) in the treatment of transfusional IO and to evaluate treatment outcomes, adverse events, and growth and sexual development of these children after 3 years follow-up period.

In this prospective, multi-center, non-interventional study, patients with 2–18 years of age with hemoglobinopathies and transfusional IO who were on or began to receive oral ICT were enrolled. Four hundred patients were planned to be included and followed for 3 years.

The clinical and demographic characteristics of the patients, comorbidities, type and dosage of oral ICT, laboratory results related to IO markers, imaging results and serious adverse events were recorded.

Four hundred ninety-two patients from 30 centers representing the Turkish patient's profiles were enrolled. This was the baseline analyses of 429 patients, of whom 407 had a primary diagnosis of beta-thalassemia major, and 22 had a primary diagnosis of sickle cell anemia (homozygous). Data about growth and sexual development were also collected and will be reported according to age groups and treatment history.

The characteristics of the patients are summarized in Table 1.

The type and dosage of current oral ICT and ICT history are presented in Table 2.

To our knowledge this is the largest prospective study in pediatric patients diagnosed with hemoglobinopathies, particularly thalassemia major, and treated with OICs due to IO caused by regular transfusions. In this analysis, we reported baseline characteristics of this pediatric cohort. It is noteworthy to report that the pretransfusion hemoglobin levels of the majority (226 of 405 patients) of the thalassemic cohort were under 9 g/dL, suggesting a suboptimal transfusion regimen. IO was followed mainly with serum ferritin (SF) levels and many patients were not monitored for cardiac or liver IO. Of 429 patients, 339 were enrolled with IO (SF>1000 ng/mL), suggesting a non effective ICT history. Of 25 beta thalassemia patients who were treated with deferiprone (DFP), 22 had SF>1000 ng/mL (mean: 2918. 31±1477. 08). The maximum dose of deferasirox (DFX) was limited by health authority to 30 mg/kg/day during the first 6 months of the 1-year enrollment period. The mean dose of DFX for the patients with SF levels >1000 ng/mL and who were treated with DFX with a dose of ≤30 mg/kg/day was 25. 38±5. 03 mg/kg/day, suggesting a suboptimal dosing for a negative iron balance. This may be one of the reasons of the high mean SF level at baseline. Moreover, the treatment duration with OICs and effectiveness of previous treatment varied. The results of this study will reflect real life experience and help us to understand obstacles in the management of IO in this patient population.

Antmen:Novartis Oncology: Speakers Bureau. Organ:Novartis Oncology: Employment. Canatar:Novartis Oncology: Employment. Koseoglu:Novartis Oncology: Consultancy.