The pharmacokinetic and safety profile of single-dose deferiprone in subjects with sickle cell disease.

Patients with sickle cell disease (SCD) who undergo repeated blood transfusions often develop iron overload. Deferiprone (Ferriprox®) is an oral iron chelator indicated for the treatment of transfusional iron overload due to thalassemia syndromes and has been recently approved as a treatment for iron overload in adult and pediatric patients with SCD and other anemias. The present study aims to characterize the pharmacokinetic (PK) profile of deferiprone (DFP) in adult subjects with SCD. In this phase I, open-label study, subjects with SCD were administered a single 1500 mg dose of DFP. Blood and urine samples were collected for PK assessments of DFP and its main metabolite, deferiprone 3-O-glucuronide (DFP-G). Eight subjects were enrolled and completed the study. Following drug administration, serum levels of DFP and DFP-G rose to maximum concentrations at 1.0 and 2.8 h post-dose, respectively. The half-lives of DFP and DFP-G were 1.5 and 1.6 h, respectively. The majority of administered drug was metabolized and excreted as DFP-G, with less than 4% excreted unchanged in urine up to 10 h post-dose. Subjects received a safety assessment 7 (± 3) days post-dose. Two subjects reported mild adverse events unrelated to the study drug, and no other safety concerns were reported. The PK profile of DFP in SCD subjects is consistent with previous reports in healthy adult volunteers, suggesting no special dosing adjustments are indicated for this population. These findings provide valuable insight for treating iron overload in patients with SCD, who have limited chelation therapy treatment options (trial registration number: NCT01835496, date of registration: April 19, 2013).

Wrist Joint Skeletal Changes in Children With Transfusion-dependent Thalassemia.

BACKGROUND: Arthropathies and bone deformities are well known to occur in patients with thalassemia major and have been attributed to the disease or to its therapy. Before the advent of chelation therapy, these children developed widened diploic space and "hair-on-end" pattern in skull, "cobweb" pattern in the pelvis, and the lack of the normal concave outline in the long bones because of extensive marrow proliferation. After the introduction of iron-chelation therapy, these patients were noted to develop metaphyseal abnormalities and vertebral changes resembling spondylo-metaphyseal dysplasia. Only one study has shown some association of deferiprone (chelating agent) use with distal ulnar changes in these children. Our study was done to describe the skeletal changes and deformities in wrist joints of children with transfusion-dependent thalassemia and correlate them with age, mean pretransfusion hemoglobin level, mean serum ferritin level, and type and duration of chelation therapy in these children. METHODS: A total of 60 children with transfusion-dependent thalassemia from the thalassemia daycare center were examined. These children were divided into 3 groups on the basis of their age (group A: 2 to 6 y, group B: 6 to 10 y, and group C: 10 to 14 y). Detailed history, including treatment history, number of blood transfusions received over the last 1 year, clinical examination, and radiologic assessment of both forearm with wrists were done. RESULTS: The clinical and radiologic differences in radial and ulnar lengths increased significantly with the increasing age of these patients, the ulna being short. There was some correlation between increasing negative ulnar variance and distal radial articular angle with deferiprone consumption. CONCLUSION: Chelation therapy, particularly with deferiprone, may cause distal ulnar growth arrest causing ulnar shortening and progressive radial bowing in these children. LEVEL OF EVIDENCE: Level IV-case series.

Combination Oral Chelation in Adult Patients With Transfusion-dependent Thalassemia and High Iron Burden.

An open-label, pilot study was conducted to evaluate deferasirox/deferiprone combination chelation therapy in adult patients with transfusion-dependent thalassemia and severe iron overload. Enrollment proved difficult. Nine patients (median age, 27.4 y; ferritin, 4965 ng/mL; liver iron concentration, 28.5 mg/g dry weight; cardiac T2*, 13.3 ms) received treatment. Two were withdrawn for treatment-related adverse effects. Arthralgia (4 patients) and gastrointestinal symptoms (5 patients) were common; no episodes of neutropenia/agranulocytosis occurred. Adherence difficulties were common. Of 6 patients with 12 to 18 months follow-up, 3 showed improvement in cardiac T2* and 2 in liver iron. Combination oral chelation may be effective but adverse effects and adherence challenges may limit efficacy.

The effect of iron chelation therapy on overall survival in sickle cell disease and ß-thalassemia: A systematic review.

Red blood cell transfusions have become standard of care for the prevention of life-threatening anemia in patients with ß-thalassemia and sickle cell disease (SCD). However, frequent transfusions can lead to accumulation of iron that can result in liver cirrhosis, diabetes mellitus, arthritis, arrhythmias, cardiomyopathy, heart failure, and hypogonadotropic hypogonadism. Iron chelation therapy has been shown to reduce serum ferritin levels and liver iron content, but limitations of trial design have prevented any demonstration of improved survival. The objective of this systematic review was to investigate the impact of iron chelation therapy on overall and event-free survival in patients with ß-thalassemia and SCD. Eighteen articles discussing survival in ß-thalassemia and 3 in SCD were identified. Overall iron chelation therapy resulted in better overall survival, especially if it is instituted early and compliance is maintained. Comparative studies did not show any significant differences between available iron chelation agents, although there is evidence that deferiprone is better tolerated than deferoxamine and that compliance is more readily maintained with the newer oral drugs, deferiprone and deferasirox. Iron chelation therapy, particularly the second-generation oral agents, appears to be associated with improved overall and event-free survival in transfusion-dependent patients with ß-thalassemia and patients with SCD.

Safety and efficacy of early start of iron chelation therapy with deferiprone in young children newly diagnosed with transfusion-dependent thalassemia: A randomized controlled trial.

Iron overload is inevitable in patients who are transfusion dependent. In young children with transfusion-dependent thalassemia (TDT), current practice is to delay the start of iron chelation therapy due to concerns over toxicities, which have been observed when deferoxamine was started too early. However, doing so may increase the risk of iron accumulation that will be manifested as toxicities later in life. This study investigated whether deferiprone, a chelator with a lower affinity for iron than deferoxamine, could postpone transfusional iron overload while maintaining a good safety profile. Recently diagnosed TDT infants (N = 64 their age ranged from 10 to 18 (median 12) months, 54.7% males; receiving ≤6 transfusions; serum ferittin (SF) >400 to < 1000 ng/mL were randomized to "early start deferiprone" (.ES-DFP) at a low dose (50 mg/kg/day) or to "delay chelation" (DC), and remained in the study until their serum ferritin (SF) level reached ≥1000 µg/L. 61 patients continued the study Levels of transferrin saturation (TSAT) and labile plasma iron (LPI) were measured as well. By approximately 6 months postrandomization, 100% of the subjects in DC group had achieved SF > 1000 µg/L and TSAT > 70% compared with none in the ES-DFP group. LPI level > 0.6 µM was observed in 97% vs. 40% of the DS and ES groups, respectively, (P < 0.001). The time to reach SF > 1000 µg/L was delayed by 6 months in the ES-DFP group (P < 0.001) without escalating DFP dose. No unexpected, serious, or severe adverse events were seen in the ES-DFP group.