Safety profiles of iron chelators in young patients with haemoglobinopathies.

BACKGROUND: This review describes the safety of deferoxamine (DFO), deferiprone (DFP), deferasirox (DFX) and combined therapy in young patients less than 25 yr of age with haemoglobinopathies. METHODS: Searches in electronic literature databases were performed. Studies reporting adverse events associated with iron chelation therapy were included. Study and reporting quality was assessed using AHRQ Risk of Bias Assessment Tool and McMaster Quality Assessment Scale of Harms. Prospective clinical studies were pooled in a random-effects meta-analysis of proportions. RESULTS: Safety data of 2040 patients from 34 studies were included. Ninety-two case reports of 246 patients were identified. DFX (937 patients) and DFP (667 patients) possess the largest published safety evidence. Fewer studies on combination regimens are available. Increased transaminases were seen in all regimens (3.9-31.3%) and gastrointestinal disorders with DFP and DFX (3.7-18.4% and 5.8-18.8%, respectively). Therapy discontinuations due to adverse events were low (0-4.1%). Reporting quality was selective and poor in most of the studies. CONCLUSION: Iron chelation therapy is generally safe in young patients, and published data correspond to summary of product characteristics. Each iron chelation regimen has its specific safety risks. DFO seems not to be associated with serious adverse effects in recommended doses. In DFP and DFX, rare, but serious, adverse reactions can occur. Data on combined therapy are scarce, but it seems equally safe compared to monotherapy.

Safety Profile of Oral Iron Chelator Deferiprone in Chinese Children with Transfusion-Dependent Thalassaemia.

UNLABELLED: There is a lack of knowledge regarding the incidence of serious adverse drug reactions (ADR) to the oral iron chelator deferiprone in Chinese children with transfusion-dependent thalassaemia. In this retrospective population-based cohort study, paediatric thalassaemia patients in Hong Kong were screened for serious and medically important adverse events related to deferiprone therapy using diagnosis codes, laboratory data and hospital admissions. Potential ADRs were assessed by reviewing concomitant medications, diagnoses and laboratory data and evaluated using standardised causality assessment. Eighty-seven patients contributing 169.8 person-years were included. Thirty ADRs were identified in 21 patients. Most ADRs (56.0%) occurred in the first three months of therapy. Neutropenia occurred in 11 patients (12.6%; incidence rate 6.5 per 100 patient-years) and severe neutropenia (agranulocytosis) was observed in 5 patients (5.7%, incidence rate 2.9 per 100 patient-years). Other identified ADRs involve severe arthropathy, elevated liver enzymes and mild thrombocytopenia. In conclusion, the safety profile of DFP therapy in Chinese children suffering from transfusion-dependent thalassaemia is in line with previous studies of non-Chinese children. However, unlike previous studies, we observed a relatively high incidence of agranulocytosis and neutropenia in patients with simultaneous combined therapy. Hence close monitoring for white blood cell counts is advised in Chinese children under combined iron chelation therapy. Further prospective clinical and pharmacogenetic studies are required to better evaluate this important safety signal. KEY POINTS: • Half of the identified ADRs related to deferiprone therapy occurred during the first three months of treatment. • A relatively high incidence of agranulocytosis and neutropenia. Hence close monitoring for white blood cell counts is advised in Chinese children under combined iron chelation therapy.