Deferasirox induces regression of iron overload in patients with myelodysplastic syndromes

Ratiometric fluorescence assay based on carbon dots and Cu2+-catalyzed oxidation of O-phenylenediamine for the effective detection of deferasirox

The monitoring of deferasirox (DEF) has important clinical roles in patients who need iron excretion. However, analytical methods with practicability and simplicity are limited. Moreover, ratiometric fluorescence strategies based on Förster resonance energy transfer (FRET) from carbon dots (CDs) as a donor are rarely reported as a drug monitor. In this work, CDs with an appropriate emitting wavelength at 480 nm and excitation around 370 nm were prepared by hydrothermal approach and HCl post-treatment. O-Phenylenediamine (OPD) can be oxidized by Cu²⁺ to produce yellow fluorescent 2,3-diaminophenazine (oxOPD) in the system of Cu²⁺ and OPD (Cu–OPD). Correspondingly, a remarkable FRET from CDs to oxOPD in the system of CDs, Cu²⁺ and OPD (CDs–Cu–OPD) was fabricated with the quenching illustration of CDs, but emitting property of oxOPD. Attributed to the chelation ability of DEF on Cu²⁺, the inhibitory effects of DEF on the Cu²⁺-triggered oxidative capability reduced the FRET system by the decreased oxOPD. Thus, the recovered CDs at F₄₈₀ and decreased oxOPD at F₅₆₀ were found through a ratiometric mode by the addition of DEF in CDs–Cu–OPD for the DEF assay. The FRET behavior of CDs and oxOPD in CDs–Cu–OPD was proved clearly through the calculation of the association constant, binding constant, number of binding sites, and the distance between the donor and acceptor. Furthermore, this ratiometric method exhibited promising analytical performance for DEF with the application in real samples. The implementation of this work expands the application field of CDs and OPD oxidation in drug monitoring, and even other biological analyses through ratiometric strategy.

CDs with appropriate emission property interacted with Cu²⁺-catalyzed oxidation of OPD to form a ratiometric fluorescence strategy for deferasirox (DEF) detection.

Sensitive determination of deferasirox in blood of patients with thalassemia using dispersive liquid-liquid microextraction based on solidification of floating organic drop followed by HPLC-UV

Deferasirox is an oral iron chelator that has been on the market since 2005 and has been a suitable replacement for injectable chelators. It is important to check the amount of this drug in the blood of patients due to side effects. In this study, a new dispersive liquid-liquid microextraction based on solidification of floating drganic drop (DLLME - SFO) was applied to the extraction of deferasirox in the blood of patients with thalassemia prior to its analysis by high-performance liquid chromatography-ultraviolet detection (HPLC - UV). In this method, two long alcohols of the normal chain are mixed in a particular ratio, and then it is injected into the sample solution, which is on the magnetic stirrer. In this case, the mixture of the two alcohol changes to new double-solvent aggregate. This new double-solvent system is used as an extractant, which has a higher extraction power than any of its components alone. Under the optimum conditions, the calibration graph was linear in the rage of 0.2-200 μg L^-1 with detection limit of 0.06 μg L^-1. Repeatability (intra-day) and reproducibility (inter-day) of method based on seven replicate measurements of 100.0 μg L^-1of deferasirox were 3.8 % and 5.7 %, respectively. The results showed that DLLME - SFO is a very simple, inexpensive, environmental friendly, sensitive and efficient analytical method for the determination of trace amount of drugs in biological samples and suitable results were obtained.

Diagnosis, management and response criteria of iron overload in myelodysplastic syndromes (MDS): updated recommendations of the Austrian MDS platform

INTRODUCTION

Despite the availability of effective iron chelators, transfusion-related morbidity is still a challenge in chronically transfused patients with myelodysplastic syndromes (MDS). In these patients, transfusion-induced iron overload may lead to organ dysfunction or even organ failure. In addition, iron overload is associated with reduced overall survival in MDS. Areas covered: During the past 10 years, various guidelines for the management of MDS patients with iron overload have been proposed. In the present article, we provide our updated recommendations for the diagnosis, prevention and therapy of iron overload in MDS. In addition, we propose refined treatment response criteria. As in 2006 and 2007, recommendations were discussed and formulated by participants of our Austrian MDS platform in a series of meetings in 2016 and 2017. Expert commentary: Our updated recommendations should support early recognition of iron overload, optimal patient management and the measurement of clinical responses to chelation treatment in daily practice.

Deferasirox for managing iron overload in people with myelodysplastic syndrome

BACKGROUND

The myelodysplastic syndrome (MDS) comprises a diverse group of haematopoietic stem cell disorders. Due to symptomatic anaemia, most people with MDS require supportive therapy including repeated red blood cell (RBC) transfusions. In combination with increased iron absorption, this contributes to the accumulation of iron resulting in secondary iron overload and the risk of organ dysfunction and reduced life expectancy. Since the human body has no natural means of removing excess iron, iron chelation therapy, i.e. the pharmacological treatment of iron overload, is usually recommended. However, it is unclear whether or not the newer oral chelator deferasirox leads to relevant benefit.

OBJECTIVES

To evaluate the effectiveness and safety of oral deferasirox for managing iron overload in people with myelodysplastic syndrome (MDS).

SEARCH METHODS

We searched the following databases up to 03 April 2014: MEDLINE, EMBASE, The Cochrane Library, Biosis Previews, Web of Science, Derwent Drug File and four trial registries: Current Controlled Trials (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), ICTRP (www.who.int./ictrp/en/), and German Clinical Trial Register (www.drks.de).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing deferasirox with no therapy, placebo or with another iron-chelating treatment schedule.

DATA COLLECTION AND ANALYSIS

We did not identify any trials eligible for inclusion in this review.

MAIN RESULTS

No trials met our inclusion criteria. However, we identified three ongoing and one completed trial (published as an abstract only and in insufficient detail to permit us to decide on inclusion) comparing deferasirox with deferoxamine, placebo or no treatment.

AUTHORS' CONCLUSIONS

We planned to report evidence from RCTs that evaluated the effectiveness of deferasirox compared to either placebo, no treatment or other chelating regimens, such as deferoxamine, in people with MDS. However, we did not identify any completed RCTs addressing this question.We found three ongoing and one completed RCT (published as an abstract only and in insufficient detail) comparing deferasirox with deferoxamine, placebo or no treatment and data will hopefully be available soon. These results will be important to inform physicians and patients on the advantages and disadvantages of this treatment option.

Use of deferasirox in transfusion-dependent myelodysplastic syndromes with iron overload

SUMMARY 

In myelodysplastic syndromes (MDS), transfusion-dependent anemia has been established as an independent risk factor for decreased survival. Although evidence from prospective studies is still lacking, several guidelines recommend iron-chelating therapy in MDS patients with a longer life expectancy. With the recent introduction of deferasirox, an oral active iron-chelating drug, which has shown dose-dependent efficacy and acceptable tolerability, this therapeutic option has become feasible even in the elderly. Several retrospective and prospective studies showed that in MDS patients deferasirox is effective in reducing iron burden and in maintaining the circulating toxic iron fraction within the normal range. Moreover, in a substantial fraction of patients treated with deferasirox a significant improvement of peripheral cytopenias may occur.

Deferasirox: appraisal of safety and efficacy in long-term therapy

Deferasirox is a once-daily, oral iron chelator that is widely used in the management of patients with transfusional hemosiderosis. Several Phase II trials along with their respective extension studies as well as a Phase III trial have established the efficacy and safety of this novel agent in transfusion-dependent patients with β-thalassemia, sickle-cell disease and bone marrow-failure syndromes, including myelodysplastic syndrome and aplastic anemia. Data from various clinical trials show that a deferasirox dose of 20 mg/kg/day stabilizes serum ferritin levels and liver iron concentration, while a dose of 30-40 mg/kg/day reduces these parameters and achieves negative iron balance in red cell transfusion-dependent patients with iron overload. Across various pivotal clinical trials, deferasirox was well tolerated, with the most common adverse events being gastrointestinal disturbances, skin rash, nonprogressive increases in serum creatinine, and elevations in liver enzyme levels. Longer-term extension studies have also confirmed the efficacy and safety of deferasirox. However, it is essential that patients on deferasirox therapy are monitored regularly to ensure timely management for any adverse events that may occur with long-term therapy.

Efficacy and safety of deferasirox in myelodysplastic syndromes

Transfusion dependence in myelodysplastic syndrome (MDS) patients may lead to organ damage due to accumulation of non-transferrin-bound iron with consequent increased oxidative stress. Iron chelation has been reported in retrospective studies to improve overall survival in low-risk MDS patients, but this information needs to be validated in prospective trials. The oral iron chelator, deferasirox, has been shown to reduce serum ferritin levels in chelation naïve and pre-treated patients and to reduce labile plasma iron, independently from the efficacy on iron overload. Deferasirox is a potent NF-kB inhibitor, tested in vivo and on acute myeloid leukemia and MDS cell lines, and this effect may explain in part the phenomenon of hematological improvements reported in case reports and in different clinical trials. The drug has an acceptable safety profile, with the most common side effects reported being non-progressive change in serum creatinine level, gastrointestinal disturbances, and skin rash. In this review, we report the results of different studies testing safety and efficacy of deferasirox in MDS patients, side effects associated with the drug, and suggested management of iron overload.

Improvement in hematopoiesis after iron chelation therapy with deferasirox in patients with aplastic anemia

Iron overload due to regular transfusions of packed red cells can cause multiple organ damage. Iron chelation therapy (ICT) is important in patients with aplastic anemia (AA) who require blood transfusions as supportive management. With the introduction of the oral iron chelator deferasirox, ICT has become more widely available and feasible. We studied 4 adult AA patients who had transfusion-induced iron overload and showed hematological improvement after ICT with oral deferasirox. Following deferasirox treatment, hemoglobin increased and serum ferritin levels decreased, and the patients subsequently became transfusion independent. Our experience raises the possibility of the potential benefit of ICT on hematopoiesis. Further long-term studies in larger patient cohorts are needed to clarify the effect of the restoration of hematopoiesis after iron chelation therapy.

Improvement of iron-mediated oxidative DNA damage in patients with transfusion-dependent myelodysplastic syndrome by treatment with deferasirox

Myelodysplastic syndrome (MDS) is characterized by dysplastic and ineffective hematopoiesis, peripheral blood cytopenias, and a risk of leukemic transformation. Most MDS patients eventually require red blood cell (RBC) transfusions for anemia and consequently develop iron overload. Excess free iron in cells catalyzes generation of reactive oxygen species that cause oxidative stress, including oxidative DNA damage. However, it is uncertain how iron-mediated oxidative stress affects the pathophysiology of MDS. This study included MDS patients who visited our university hospital and affiliated hospitals (n=43). Among them, 13 patients received iron chelation therapy when their serum ferritin (SF) level was greater than 1000 ng/mL or they required more than 20 RBC transfusions (or 100 mL/kg of RBC). We prospectively analyzed 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in peripheral blood mononuclear cells (PBMC) obtained from MDS patients before and after iron chelator, deferasirox, administration. We showed that the 8-OHdG levels in MDS patients were significantly higher than those in healthy volunteers and were positively correlated with SF and chromosomal abnormalities. Importantly, the 8-OHdG levels in PBMC of MDS patients significantly decreased after deferasirox administration, suggesting that iron chelation reduced oxidative DNA damage. Thus, excess iron could contribute to the pathophysiology of MDS and iron chelation therapy could improve the oxidative DNA damage in MDS patients.

Improvement in liver pathology of patients with β-thalassemia treated with deferasirox for at least 3 years

BACKGROUND & AIMS

Most data on the effects of iron chelation therapy for patients with liver fibrosis come from small studies. We studied the effects of the oral iron chelator deferasirox on liver fibrosis and necroinflammation in a large population of patients with iron overload β-thalassemia.

METHODS

We studied data from 219 patients with β-thalassemia, collected from histologic analyses of biopsy samples taken at baseline and after at least 3 years of treatment with deferasirox. Treatment response was assessed from liver iron concentrations at baseline and the end of the study. Liver fibrosis, necroinflammation, and markers of iron overload and liver enzymes were recorded. Patients were also assessed, by serologic analysis at baseline, for hepatitis C virus infection.

RESULTS

By the end of the study, stability of Ishak fibrosis staging scores (change of -1, 0, or +1) or improvements (change of ≤-2) were observed in 82.6% of patients; Ishak necroinflammatory scores improved by a mean value of -1.3 (P<.001). Improvements in fibrosis stage and necroinflammation were independent of hepatitis C virus exposure or reduction in liver iron concentration defined by the response criteria. Absolute changes in concentrations of liver iron by the end of the study did not correlate with improved Ishak fibrosis or necroinflammatory scores.

CONCLUSIONS

Deferasirox treatment for 3 or more years reversed or stabilized liver fibrosis in 83% of patients with iron-overloaded β-thalassemia. This therapeutic effect was independent of reduced concentration of liver iron (defined by the response criteria) or previous exposure to hepatitis C virus.

Importance of optimal dosing ≥ 30 mg/kg/d during deferasirox treatment: 2.7-yr follow-up from the ESCALATOR study in patients with β-thalassaemia

Following 1-yr deferasirox therapy in the ESCALATOR study, 57% of previously chelated patients with β-thalassaemia achieved treatment success (maintenance of or reduction in liver iron concentration (LIC) vs. baseline LIC). Seventy-eight per cent had dose increases at median of 26 wk, suggesting that 1-yr results may not have reflected full deferasirox efficacy. Extension data are presented here. Deferasirox starting dose was 20 mg/kg/d (increases to 30/40 mg/kg/d permitted in the core/extension, respectively). Efficacy was primarily assessed by absolute change in LIC and serum ferritin. Overall, 231 patients received deferasirox in the extension; 67.4% (P < 0.0001) achieved treatment success. By the end of the extension, 66.2% of patients were receiving doses ≥30 mg/kg/d. By the end of the 1-yr extension, mean LIC had decreased by 6.6 ± 9.4 mg Fe/g dw (baseline 19.6 ± 9.2; P < 0.001) and median serum ferritin by 929 ng/mL (baseline 3356; P < 0.0001). There was a concomitant improvement in liver function markers (P < 0.0001). Fewer drug-related adverse events were reported in extension than core study (23.8% vs. 44.3%). Doses ≥30 mg/kg/d were generally required because of high transfusional iron intake and high baseline serum ferritin levels, highlighting the importance of administering an adequate dose to achieve net negative iron balance.

Deferasirox for managing iron overload in people with myelodysplastic syndrome

BACKGROUND

The myelodysplastic syndrome (MDS) comprises a diverse group of haematopoietic stem cell disorders. Due to symptomatic anaemia most patients require supportive therapy including repeated red blood cell (RBC) transfusions. In combination with increased iron absorption, this contributes to the accumulation of iron resulting in secondary iron overload and the risk of organ dysfunction and reduced life expectancy. Since the human body has no natural means of getting rid of excess iron, iron chelation therapy is usually recommended. However, whether the new oral chelator deferasirox leads to relevant benefit is unclear.

OBJECTIVES

To assess the effectiveness and safety of oral deferasirox in people with myelodysplastic syndrome and iron overload.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, The Cochrane Library, Biosis Previews, Web of Science, Derwent Drug File, XTOXLINE and three trial registries: Current Controlled Trials: www.controlled-trials.com, ClinicalTrials.gov: www.clinicaltrials.gov, ICTRP: www.who.int./ictrp/en/. Most recent searches of these databases: June 2010.

SELECTION CRITERIA

Randomised controlled trials comparing deferasirox with no therapy/placebo or with another iron chelating treatment schedule.

DATA COLLECTION AND ANALYSIS

No studies eligible for inclusion in this review were identified.

MAIN RESULTS

No studies were included in this review. However, we identified one ongoing study comparing deferasirox with deferoxamine.

AUTHORS' CONCLUSIONS

We planned to report evidence from randomised clinical trials evaluating the effectiveness of deferasirox compared to either placebo/no treatment or other chelating regimens such as deferoxamine in people with myelodysplastic syndrome. However, no completed randomised trials addressing this question could be identified.One ongoing randomised study comparing deferasirox with placebo was identified and preliminary data will hopefully be available soon. These results will be important to inform physicians and patients on the advantages and disadvantages of this treatment option.

Towards a unifying, systems biology understanding of large-scale cellular death and destruction caused by poorly liganded iron: Parkinson's, Huntington's, Alzheimer's, prions, bactericides, chemical toxicology and others as examples

Exposure to a variety of toxins and/or infectious agents leads to disease, degeneration and death, often characterised by circumstances in which cells or tissues do not merely die and cease to function but may be more or less entirely obliterated. It is then legitimate to ask the question as to whether, despite the many kinds of agent involved, there may be at least some unifying mechanisms of such cell death and destruction. I summarise the evidence that in a great many cases, one underlying mechanism, providing major stresses of this type, entails continuing and autocatalytic production (based on positive feedback mechanisms) of hydroxyl radicals via Fenton chemistry involving poorly liganded iron, leading to cell death via apoptosis (probably including via pathways induced by changes in the NF-κB system). While every pathway is in some sense connected to every other one, I highlight the literature evidence suggesting that the degenerative effects of many diseases and toxicological insults converge on iron dysregulation. This highlights specifically the role of iron metabolism, and the detailed speciation of iron, in chemical and other toxicology, and has significant implications for the use of iron chelating substances (probably in partnership with appropriate anti-oxidants) as nutritional or therapeutic agents in inhibiting both the progression of these mainly degenerative diseases and the sequelae of both chronic and acute toxin exposure. The complexity of biochemical networks, especially those involving autocatalytic behaviour and positive feedbacks, means that multiple interventions (e.g. of iron chelators plus antioxidants) are likely to prove most effective. A variety of systems biology approaches, that I summarise, can predict both the mechanisms involved in these cell death pathways and the optimal sites of action for nutritional or pharmacological interventions.

Iron chelation therapy with deferasirox in patients with aplastic anemia: a subgroup analysis of 116 patients from the EPIC trial

The prospective 1-year Evaluation of Patients' Iron Chelation with Exjade (EPIC) study enrolled a large cohort of 116 patients with aplastic anemia; the present analyses evaluated the efficacy and safety of deferasirox in this patient population. After 1 year, median serum ferritin decreased significantly from 3254 ng/mL at baseline to 1854 ng/mL (P < .001). Decreases occurred in chelation-naive (3229-1520 ng/mL; P < .001, last-observation-carried-forward analysis), and previously chelated (3263-2585 ng/mL; P = .21, last-observation-carried-forward analysis) patients and were reflective of dose adjustments and ongoing iron intake. Baseline labile plasma iron levels were within normal range despite high serum ferritin levels. The most common drug-related adverse events were nausea (22%) and diarrhea (16%). Serum creatinine increases more than 33% above baseline and the upper limit of normal occurred in 29 patients (25%), but there were no progressive increases; concomitant use of cyclosporine had a significant impact on serum creatinine levels. The decrease in mean alanine aminotransferase levels at 1 year correlated significantly with reduction in serum ferritin (r = 0.40, P < .001). Mean absolute neutrophil and platelet counts remained stable during treatment, and there were no drug-related cytopenias. This prospective dataset confirms the efficacy and well characterizes the tolerability profile of deferasirox in a large population of patients with aplastic anemia. This study was registered at www.clinicaltrials.gov as #NCT00171821.

Iron chelation therapy in MDS: what have we learnt recently?

Patients with myelodysplastic syndromes (MDS) who receive chronic blood transfusions for anaemia are at risk of developing iron overload, which can negatively affect organ function and survival. Evidence suggests that iron chelation therapy can restore iron balance in these patients and may improve their chances of survival. Recently, several guidelines on the management of patients with MDS have been published that address iron overload and the use of iron chelation therapy. While these guidelines differ in some specific details, they generally agree that patients with lower-risk MDS are most likely to develop iron overload and therefore benefit from iron chelation therapy. The oral iron chelator, deferasirox, has been shown to reduce serum ferritin levels and labile plasma iron in patients with MDS, and has an acceptable safety profile. Unlike other iron chelators, deferasirox also appears to inhibit the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) pathway in MDS blast cells, which may lead to additional beneficial effects.

Clinical consequences of iron overload from chronic red blood cell transfusions, its diagnosis, and its management by chelation therapy

Iron overload from chronic transfusion therapy can be extremely toxic. Excess transfusional iron is deposited in the liver, heart, and other organs as free iron, which can cause organ dysfunction and damage over time. Increased awareness of the risk of iron overload in patients requiring chronic transfusion therapy is needed, and such patients should be screened for hyperferritinemia. Those with serial serum ferritin levels exceeding 1000 ng/mL and a total infused red blood cell volume of 120 mL/kg of body weight or more should be treated with chelation therapy and then monitored to ensure that treatment adequately reduces iron levels.

Update on the use of deferasirox in the management of iron overload

Regular blood transfusions as supportive care for patients with chronic anemia inevitably lead to iron overload as humans cannot actively remove excess iron. The cumulative effects of iron overload cause significant morbidity and mortality if not effectively treated with chelation therapy. Based on a comprehensive clinical development program, the once-daily, oral iron chelator deferasirox (Exjade((R))) is approved for the treatment of transfusional iron overload in adult and pediatric patients with various transfusion-dependent anemias, including beta-thalassemia and the myelodysplastic syndromes. Deferasirox dose should be titrated for each individual patient based on transfusional iron intake, current iron burden and whether the goal is to decrease or maintain body iron levels. Doses of >30 mg/kg/day have been shown to be effective with a safety profile consistent with that observed at doses <30 mg/kg/day. Recent data have highlighted the ability of deferasirox to decrease cardiac iron levels and to prevent the accumulation of iron in the heart. The long-term efficacy and safety of deferasirox for up to 5 years of treatment have now been established. The availability of this effective and generally well tolerated oral therapy represents a significant advance in the management of transfusional iron overload.