Combined chelation therapy with daily oral deferiprone and twice-weekly subcutaneous infusion of desferrioxamine in children with β-thalassemia: 3-year experience

Combination chelation therapy

Combination chelation therapies are considered in transfusion-dependent thalassemia patients for whom monotherapy regimens have failed to achieve iron balance or intensification of iron chelation therapy is required for the rapid reduction of excess iron to avoid permanent organ damage. Combination chelation may provide a more flexible approach for individualizing chelation therapy, thereby improving tolerability, adherence, and quality of life. In principle, iron chelators can be combined with an infinite number of dosing regimens; these involve simultaneous or sequential exposure to the chelators on the same day or alternating the drugs on different days. Clinical studies have established the safety and efficacy of chelation combinations. However, real-life data with combination therapies indicate the significance of compliance for a meaningful reduction in iron overload compared to monotherapies.

An evaluation of deferiprone as twice-a-day tablets or in combination therapy for the treatment of transfusional iron overload in thalassemia syndromes

INTRODUCTION

Regular blood transfusions in patients with thalassemia syndromes can cause iron overload resulting in complications including cirrhosis, heart problems, or endocrine abnormalities. To prevent iron overload toxicity in these patients, three iron chelators are currently FDA-approved for use: deferoxamine, deferasirox, and deferiprone. In the United States, deferiprone has been approved for three times daily dosing since 2011 and has recently gained approval for twice-daily administration.

AREAS COVERED

A PubMed literature search was performed with the keywords 'deferiprone' and 'thalassemia.' Relevant original research studying deferiprone's effects on transfusional iron overload in patients with thalassemia syndromes was included. Exclusion criteria included case reports and review papers. Deferiprone is effective at reducing serum ferritin levels in patients with iron overload. Twice-daily administration provides a similar level of iron chelation as three times daily dosing with a comparable side effect profile and increased patient acceptability.

EXPERT OPINION

New studies are highlighting deferiprone's potential for combination therapy with either deferoxamine or deferasirox to improve iron chelation. Deferiprone's ability to significantly decrease cardiac and liver iron content can be utilized in other transfusion-dependent hematologic conditions, as evidenced by its recent approval for use in the United States for sickle cell disease or other anemias.

Iron Chelators in Treatment of Iron Overload

Patients suffering from iron overload can experience serious complications. In such patients, various organs, such as endocrine glands and liver, can be damaged. Although iron is a crucial element for life, iron overload can be potentially toxic for human cells due to its role in generating free radicals. In the past few decades, there has been a major improvement in the survival of patients who suffer from iron overload due to the application of iron chelation therapy in clinical practice. In clinical use, deferoxamine, deferiprone, and deferasirox are the three United States Food and Drug Administration-approved iron chelators. Each of these iron chelators is well known for the treatment of iron overload in various clinical conditions. Based on several up-to-date studies, this study explained iron overload and its clinical symptoms, introduced each of the above-mentioned iron chelators, and evaluated their advantages and disadvantages with an emphasis on combination therapy, which in recent studies seems a promising approach. In numerous clinical conditions, due to the lack of accurate indicators, choosing a standard approach for iron chelation therapy can be difficult; therefore, further studies on the issue are still required. This study aimed to introduce each of these iron chelators, combination therapy, usage doses, specific clinical applications, and their advantages, toxicity, and side effects.

Using of deferasirox and deferoxamine in refractory iron overload thalassemia

BACKGROUND

Iron overload is a major complication of transfusion-dependent thalassemia (TDT) and requires iron chelation (IC) therapy. However, a combination therapy may be required for patients responding poorly to monotherapy.

METHODS

Nine TDT patients previously treated with IC were enrolled; five patients were previously treated with deferasirox (DFX) twice daily. The dose of DFX was 20-40 mg/kg/day, while the dose of deferoxamine (DFO) was 18-40 mg/kg/day for 3-6 days/week.

RESULTS

At the 6- and 12-month time points, six and eight patients demonstrated decreased serum ferritin levels, with median reductions of 707 ng/mL (range, 1,653-5,444 ng/mL) and 1,129 ng/mL (range, 1,781-7,725 ng/mL) compared to the baseline, respectively. Eight patients also had a reduced liver iron concentration (LIC), with a median reduction of 3.9 mg/g dry wt (range, 8.3-11.1 mg/g dry wt). Of the five patients treated with DFX twice daily, four responded to combination therapy. All responsive patients could finally stop DFO after the decline in LIC. Moreover, there were no treatment-related complications.

CONCLUSION

The combination of DFX and DFO proved to be effective and without significant toxicities for TDT patients who had been unresponsive to standard IC therapy. Further studies with a larger cohort size and long-term follow-up are warranted to elucidate the efficacy of the combination.

The History of Deferiprone (L1) and the Paradigm of the Complete Treatment of Iron Overload in Thalassaemia

Deferiprone (L1) was originally designed, synthesised and screened in vitro and in vivo in 1981 by Kontoghiorghes G. J. following his discovery of the novel alpha-ketohydroxypyridine class of iron chelators (1978–1981), which were intended for clinical use. The journey through the years for the treatment of thalassaemia with L1 has been a very difficult one with an intriguing turn of events, which continue until today. Despite many complications, such as the extensive use of L1 suboptimal dose protocols, the aim of chelation therapy-namely, the complete removal of excess iron in thalassaemia major patients, has been achieved in most cases following the introduction of specific L1 and L1/deferoxamine combinations. Many such patients continue to maintain normal iron stores. Thalassemia has changed from a fatal to chronic disease; also thanks to L1 therapy and thalassaemia patients are active professional members in all sectors of society, have their own families with children and grandchildren and their lifespan is approaching that of normal individuals. No changes in the low toxicity profile of L1 have been observed in more than 30 years of clinical use and prophylaxis against the low incidence of agranulocytosis is maintained using mandatory monitoring of weekly white blood cells’ count. Thousands of thalassaemia patients are still denied the cardioprotective and other beneficial effects of L1 therapy. The safety of L1 in thalassaemia and other non-iron loaded diseases resulted in its selection as one of the leading therapeutics for the treatment of Friedreich’s ataxia, pantothenate kinase-associated neurodegeneration and other similar cases. There are also increasing prospects for the application of L1 as a main, alternative or adjuvant therapy in many pathological conditions including cancer, infectious diseases and as a general antioxidant for diseases related to free radical pathology.

The Effect of Blood Transfusion on Growth of Patients with Hb E/β-Thalassemia

A retrospective evaluation of growth in 112 patients (68 males, 44 females) with Hb E (HBB: c.79G>A)/β-thalassemia (β-thal), classified as 88 transfusion-dependent thalassemia (TDT) and 24 non transfusion-dependent thalassemia (NTDT), is reported. Patients with TDT have received regular transfusions of red blood cells (RBCs) 15 mL/kg every 4 weeks to maintain pre transfusion hemoglobin (Hb) levels of at least 9.0 g/dL and were categorized according to age at initiation of regular RBC transfusion as subgroup 1, <4 years; subgroup 2, 4-10 years, and subgroup 3, >10 years. Iron chelation was initiated at the mean age of 7 years. The results revealed that patients in subgroups 1 and 2, receiving RBC transfusions at a young age (2.9 and 6.9 years, respectively), had normal prepubertal growth at enrollment and last follow-up. Patients in subgroup 3, with the lowest initial height Z-score of -2.10, were able to achieve comparable final adult height as those in subgroups 1 and 2. The mean final height of 21 males and 13 females with TDT at the ages of 18.9 and 18.7 years was 168.1 and 157.7 cm, respectively, which did not significantly differ from their midparental height and those with NTDT. Early initiation of optimal transfusion and iron chelation promoted normal prepubertal growth. However, delayed initiation of transfusion at age 12 years impaired prepubertal growth but they could achieve normal final adult height.

Single-center retrospective study of the effectiveness and toxicity of the oral iron chelating drugs deferiprone and deferasirox

BACKGROUND

Iron overload, resulting from blood transfusions in patients with chronic anemias, has historically been controlled with regular deferoxamine, but its parenteral requirement encouraged studies of orally-active agents, including deferasirox and deferiprone. Deferasirox, licensed by the US Food and Drug Administration in 2005 based upon the results of randomized controlled trials, is now first-line therapy worldwide. In contrast, early investigator-initiated trials of deferiprone were prematurely terminated after investigators raised safety concerns. The FDA declined market approval of deferiprone; years later, it licensed the drug as "last resort" therapy, to be prescribed only if first-line drugs had failed. We undertook to evaluate the long-term effectiveness and toxicities of deferiprone and deferasirox in one transfusion clinic.

METHODS AND FINDINGS

Under an IRB-approved study, we retrospectively inspected the electronic medical records of consented iron-loaded patients managed between 2009 and 2015 at The University Health Network (UHN), Toronto. We compared changes in liver and heart iron, adverse effects and other outcomes, in patients treated with deferiprone or deferasirox.

RESULTS

Although deferiprone was unlicensed in Canada, one-third (n = 41) of locally-transfused patients had been switched from first-line, licensed therapies (deferoxamine or deferasirox) to regimens of unlicensed deferiprone. The primary endpoint of monitoring in iron overload, hepatic iron concentration (HIC), increased (worsened) during deferiprone monotherapy (mean 10±2-18±2 mg/g; p < 0.0003), exceeding the threshold for life-threatening complications (15 mg iron/g liver) in 50% patients. During deferasirox monotherapy, mean HIC decreased (improved) (11±1-6±1 mg/g; p < 0.0001). Follow-up HICs were significantly different following deferiprone and deferasirox monotherapies (p < 0.0000002). Addition of low-dose deferoxamine (<40 mg/kg/day) to deferiprone did not result in reductions of HIC to <15 mg/g (baseline 20±4 mg/g; follow-up, 18±4 mg/g; p < 0.2) or in reduction in the proportion of patients with HIC exceeding 15 mg/g (p < 0.2). During deferiprone exposure, new diabetes mellitus, a recognized consequence of inadequate iron control, was diagnosed in 17% patients, most of whom had sustained HICs exceeding 15 mg/g for years; one woman died after 13 months of a regimen of deferiprone and low-dose deferasirox. During deferiprone exposure, serum ALT increased over baseline in 65% patients. Mean serum ALT increased 6.6-fold (p < 0.001) often persisting for years. During deferasirox exposure, mean ALT was unchanged (p < 0.84). No significant differences between treatment groups were observed in the proportions of patients estimated to have elevated cardiac iron.

CONCLUSIONS

Deferiprone showed ineffectiveness and significant toxicity in most patients. Combination with low doses of first-line therapies did not improve the effectiveness of deferiprone. Exposure to deferiprone, over six years while the drug was unlicensed, in the face of ineffectiveness and serious toxicities, demands review of the standards of local medical practice. The limited scope of regulatory approval of deferiprone, worldwide, should restrict its exposure to the few patients genuinely unable to tolerate the two effective, first-line therapies.

Clinico-haematological profile of patients with bicytopenia

Bicytopenia is the reduction of any of the two cell lines of blood, i.e., erythrocytes, leukocytes or platelets. Many studies are done on pancytopenia but very few studies exist in the literature evaluating the spectrum of aetiologies of bicytopenia. To date, no study is available on bicytopenia in adults. We aimed to study the clinico-haematological profile of patients with bicytopenia and to investigate the different aetiologies of bicytopenia. Four hundred patients with bicytopenia admitted to KLE Dr. Prabhakar Kore Charitable Hospital and Medical Research Centre were selected using systematic random sampling and included in the study. Their clinical profiles and haematological parameters were evaluated. Bicytopenia was observed in all ages with the mean age being 30.7 years. The occurrence of bicytopenia in different age groups was 6% in neonates, 7% in infants, 25% in children, 17% in teenagers, 85% in adults and 11% in elderly. The most common bicytopenia observed was anaemia with thrombocytopenia (61%) followed by anaemia with leukopenia (26%) and leukopenia with thrombocytopenia (13%). The male to female ratio was 1.6:1. The most common aetiology of bicytopenia was found to be non-malignant (56%) followed by infectious (31.7%), malignant (8.3%) and drug-induced (4%). Megaloblastic anaemia was the predominant aetiology among the non-malignant group, closely followed by immune thrombocytopenic purpura and alcoholic liver disease. The most common infectious disease was dengue (12%). Signs like lymphadenopathy, splenomegaly and hepatomegaly were most significantly associated with haematological malignancies (p < 0.001). Pallor, bleeding, hepatomegaly and splenomegaly were most frequent in non-malignant conditions (p < 0.001). Fever and lymphadenopathy were most frequent in the infectious category (p < 0.001). The most prevalent signs in drug-induced aetiology were lymphadenopathy, hepatomegaly and splenomegaly (p < 0.001). Bicytopenia is a good haematological indicator for many non-malignant and malignant diseases. Knowledge of its aetiologies can help in the diagnosis and efficient management of patients.

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.

Rationale for the Successful Management of EDTA Chelation Therapy in Human Burden by Toxic Metals

Exposure to environmental and occupational toxicants is responsible for adverse effects on human health. Chelation therapy is the only procedure able to remove toxic metals from human organs and tissue, aiming to treat damage related to acute and/or chronic intoxication. The present review focuses on the most recent evidence of the successful use of the chelating agent ethylenediaminetetraacetic acid (EDTA). Assessment of toxic-metal presence in humans, as well as the rationale of EDTA therapy in cardiovascular and neurodegenerative diseases, is reported.

Deferiprone Enhances Temozolomide Cytotoxicity in Glioma Cells

Glioblastoma is the most malignant primary brain tumor with a median survival of 15 months. Temozolomide (TMZ) is the standard of care for these patients. Iron chelators have been shown to have anti-tumor activity; however, deferiprone (DFP), an orally administered iron chelator, has not been previously evaluated in gliomas. In the present study, we found that combination treatment in glioma cells with TMZ and DFP significantly reduced cell viability, produced cell cycle arrest at G2/M phase, and enhanced apoptosis. TMZ and DFP might be a potent new combination treatment for glioblastoma.

Efficient attenuation of Friedreich's ataxia (FRDA) cardiomyopathy by modulation of iron homeostasis-human induced pluripotent stem cell (hiPSC) as a drug screening platform for FRDA

BACKGROUND

Friedreich's ataxia (FRDA), a recessive neurodegenerative disorder commonly associated with hypertrophic cardiomyopathy, is caused by silencing of the frataxin (FXN) gene encoding the mitochondrial protein involved in iron-sulfur cluster biosynthesis.

METHODS

Application of our previously established FRDA human induced pluripotent stem cell (hiPSC) derived cardiomyocytes model as a platform to assess the efficacy of treatment with either the antioxidant coenzyme Q10 analog, idebenone (IDE) or the iron chelator, deferiprone (DFP), which are both under clinical trial.

RESULTS

DFP was able to more significantly suppress synthesis of reactive oxygen species (ROS) than IDE at the dosages of 25 μM and 10nM respectively which agreed with the reduced rate of intracellular accumulation of iron by DFP treatment from 25 to 50 μM. With regard to cardiac electrical-contraction (EC) coupling function, decay velocity of calcium handling kinetics in FRDA-hiPSC-cardiomyocytes was significantly improved by DFP treatment but not by IDE. Further mechanistic studies revealed that DFP also modulated iron induced mitochondrial stress as reflected by mitochondria network disorganization and decline level of respiratory chain protein, succinate dehydrogenase (CxII) and cytochrome c oxidase (COXIV). In addition, iron-response protein (IRP-1) regulatory loop was overridden by DFP as reflected by resumed level of ferritin (FTH) back to basal level and the attenuated transferrin receptor (TSFR) mRNA level suppression thereby reducing further iron uptake.

CONCLUSIONS

DFP modulated iron homeostasis in FRDA-hiPSC-cardiomyocytes and effectively relieved stress-stimulation related to cardiomyopathy. The resuming of redox condition led to the significantly improved cardiac prime events, cardiac electrical-coupling during contraction.

Iron Chelation in Thalassemia Major

PURPOSE

Iron chelation has improved survival and quality of life of patients with thalassemia major. there are currently 3 commercially available iron-chelating drugs with different pharmacokinetic and pharmacodynamic activity. The choice of adequate chelation treatment should be tailored to patient needs and based on up-to-date scientific evidence.

METHODS

A review of the most recent literature was performed.

FINDINGS

The ability of the chelators to bind the redox active component of iron, labile plasma iron, is crucial for protecting the cells. Chelation therapy should be guided by magnetic resonance imaging that permits the tailoring of therapy according to the needs of the patient because different chelators preferentially clear iron from different sites. Normal levels of body iron seem to decrease the need for hormonal and cardiac therapy.

IMPLICATIONS

The 3 chelators currently available have different benefits, different safety profiles, and different acceptance on the part of the patients. Good-quality, well-designed, randomized, long-term clinical trials continue to be needed.