Iron overload is the primary cause of mortality and morbidity in thalassemia major despite advances in chelation therapy. We performed a pilot clinical trial to evaluate the safety and efficacy of combined therapy with deferasirox (DFX, 20-30 mg/kg daily) and deferoxamine (DFO, 35-50 mg/kg on 3-7 days/week) in 22 patients with persistent iron overload or organ damage. In the 18 subjects completing 12 months of therapy, median liver iron concentration decreased by 31% from 17.4 mg/g (range 3.9-38.2 mg/g) to 12.0 mg/g (range 0.96-26.7 mg/g, P<0.001). Median ferritin decreased by 24% from 2,465 ng/mL (range 1,110-10,700 ng/mL) to 1,875 ng/mL (range 421-5,800 ng/mL, p=0.002). All 6 subjects with elevated myocardial iron showed improvement in MRI T2* (p=0.031). The mean ± S.E. plasma non-transferrin-bound iron (NTBI) declined from 3.10 ± 0.25 μM to 2.15 ± 0.29 μM (p=0.028). The administration of DFX during infusion of DFO further lowered NTBI (-0.28 ±0.08 μM, p=0.004) and labile plasma iron (LPI, -0.03 ± 0.01 μM, p=0.006). The simultaneous administration of DFO and DFX rapidly reduced systemic and myocardial iron, and provided an excellent control of the toxic labile plasma iron species without an increase in toxicity.
Thalassemia Major; Iron overload; Deferoxamine; Deferasirox
A meta-analysis was conducted to investigate the efficacy and safety of three main iron chelators, namely, deferoxamine (DFO), deferiprone (DFP) and deferasirox (DFX) for thalassemia major (TM) patients.
Randomized controlled trials comparing mono-therapy DFO, DFP, DFX and combined DFP with DFO therapy in TM patients from January 1990 to December 2012 were searched and selected. Two independent authors assessed data from extracted randomized trials for efficacy and safety in the measurements of serum ferritin (SF), live iron concentration (LIC), myocardial iron content (MIC), left ventricular ejection fraction (LVEF) and adverse events (AEs).
Sixteen studies were selected. In the comparison of DFP versus DFO treatment groups, a significant difference was revealed on MIC and LVEF (P=0.01 and P=0.007, respectively) but not on SF or LIC level (P=0.65 and P=0.37, respectively). In comparing combined therapy (DFP plus DFO) versus DFO, a significant difference was shown on MIC and LVEF measurements (P<0.00001 and P=0.003, respectively), but not on SF or LIC levels (P=0.93 and P=0.62, respectively). Moreover, the combined DFP with DFO treatment had significantly higher risk than DFO treatment (RR 1.46 with 95%CI 1.04 to 2.04). When comparing DFX with DFO, a significant difference was shown on the SF level (P=0.003), and there was no difference between DFX and DFO in safety evaluation (RR 1.53 with 95%CI 0.31 to 7.49).
Findings indicated that the most effective and safe iron chelators remains to be proven, and further large-scale, long-term studies are needed.
Patients with β-thalassaemia major experience chronic iron overload due to regular blood transfusions. Chronic iron overload can be treated using iron-chelating therapies such as desferrioxamine (DFO), deferiprone (DFP) and deferasirox (DFX) monotherapy, or DFO–DFP combination therapy.
This study evaluated the relative cost effectiveness of these regimens over a 5-year timeframe from a UK National Health Service (NHS) perspective, including personal and social services.
A Markov model was constructed to evaluate the cost effectiveness of the treatment regimens over 5 years. Based on published randomized controlled trial evidence, it was assumed that all four treatment regimens had a comparable effect on serum ferritin concentration (SFC) and liver iron concentration (LIC), and that DFP was more effective for reducing cardiac morbidity and mortality. Published utility scores for route of administration were used, with subcutaneously administered DFO assumed to incur a greater quality of life (QoL) burden than the oral chelators DFP and DFX. Healthcare resource use, drug costs (2010/2011 costs), and utilities associated with adverse events were also considered, with the effect of varying all parameters assessed in sensitivity analysis. Incremental costs and quality-adjusted life-years (QALYs) were calculated for each treatment, with cost effectiveness expressed as incremental cost per QALY. Assumptions that DFP conferred no cardiac morbidity, mortality, or morbidity and mortality benefit were also explored in scenario analysis.
DFP was the dominant strategy in all scenarios modelled, providing greater QALY gains at a lower cost. Sensitivity analysis showed that DFP dominated all other treatments unless the QoL burden associated with the route of administration was greater for DFP than for DFO, which is unlikely to be the case. DFP had >99 % likelihood of being cost effective against all comparators at a willingness-to-pay threshold of £20,000 per QALY.
In this analysis, DFP appeared to be the most cost-effective treatment available for managing chronic iron overload in β-thalassaemia patients. Use of DFP in these patients could therefore result in substantial cost savings.
Electronic supplementary material
The online version of this article (doi:10.1007/s40273-013-0076-z) contains supplementary material, which is available to authorized users.
By performing regular blood transfusion and iron chelation therapy, most patients with beta thalassemia major (BTM) now survive beyond the third decade of life. Liver disease is becoming an important cause of morbidity and mortality in these patients. Chronic hepatitis and/or severe iron overload are both important causes of liver pathology. Iron chelation with desferrioxamine (DFO) reduces excessive body iron, but its efficacy is limited by poor compliance and dose related toxicity. The recent use of Deferasirox ( DFX ), an oral single dose therapy, has improved the compliance to chelation.
To study the long-term liver functions in BMT patients, seronegative for liver infections before versus after DFX treatment in relation to ferritin level.
Only BTM patients with hepatitis negative screening (checked every year) and on treatment with DFO for at least five years and with DFX for four years were enrolled. Liver function tests including serum bilirubin, alanine transferase (ALT), aspartate transferase (AST), albumin, insulin-like growth factor – I (IGF-I) and serum ferritin concentrations were followed every six months in 40 patients with BTM.
DFX treatment (20 mg/kg/day) significantly decreased serum ferritin level in patients with BTM; this was associated with a significant decrease in serum ALT, AST, ALP and increase in IGF-I concentrations. Albumin concentrations did not change after DFX treatment. ALT and AST levels were correlated significantly with serum ferritin concentrations ( r = 0.45 and 0.33 respectively, p < 0.05). IGF-I concentrations were correlated significantly with serum ALT (r= 0.26, p = 0.05) but not with AST, ALP, bilirubin or albumin levels.
The negative correlation between serum ferritin concentrations and ALT suggests that the impairment of hepatic function negatively affect IGF-I synthesis in these patients due to iron toxicity, even in the absence of hepatitis.
Some impairment of liver function can occur in hepatitis negative thalassemic patients with iron overload. The use of DFX was associated with mild but significant reduction of ALT, AST and ALP and increase in IGF-I levels. The negative correlation between IGF-I and ALT concentrations suggest that preventing hepatic dysfunction may improve the growth potential in these patients.
Cardiac complications because of transfusional iron overload are the main cause of death in thalassaemia major. New chelators and iron monitoring methods such as cardiac magnetic resonance (CMR) became available after the year 2000. We evaluated the impact of these new management options on cardiac mortality and morbidity.
The risk of cardiac death during 1990–1999 and 2000–2008 was compared. Furthermore, after 1999, morbidity, mortality and reversal of heart failure were evaluated according to chelation regime: desferrioxamine (DFO), deferiprone (DFP) and combination therapy of DFO and DFP. We also present preliminary results for deferasirox (DFX), a new oral chelator.
Three hundred and fifty-four patients were included in the de novo cardiac event evaluation, while 86 were included in the improvement component. The annual risk of cardiac death in patients aged between 20–30 and 30–40 reduced from 1.52% to 0.67% and 1.87% to 0.56%, respectively, before and after the year 2000. The risk for a de novo cardiac event for DFO was 9.1 times greater than that of DFP and 23.6 than with the combination of DFP and DFO. For DFX, there was one cardiac event over 269 patient-years. The risk of cardiac death was 9.5 per 1000 patient-years for DFO, 2.5 on DFP, 1.4 on combination. In the DFX group no cardiac deaths were recorded. The odds of improvement were 8.5 times greater with DFP and 6.1 with combination therapy compared to DFO.
The new chelation regimes, together with CMR have contributed significantly to the reduction in cardiac morbidity and mortality in patients with thalassaemia major.
thalassaemia major; cardiac disease; desferrioxamine; deferiprone; deferasirox; transfusional iron overload
Deferasirox effectively controls liver iron concentration; however, little is known regarding its ability to remove stored cardiac iron. Deferiprone seems to have increased cardiac efficacy compared with traditional deferoxamine therapy. Therefore, the relative efficacy of deferasirox and deferiprone were compared in removing cardiac iron from iron-loaded gerbils.
Twenty-nine 8- to 10-week-old female gerbils underwent 10 weekly iron dextran injections of 200 mg/kg/week. Prechelation iron levels were assessed in 5 animals, and the remainder received deferasirox 100 mg/kg/D po QD (n = 8), deferiprone 375 mg/kg/D po divided TID (n = 8), or sham chelation (n = 8), 5 days/week for 12 weeks.
Deferasirox reduced cardiac iron content 20.5%. No changes occurred in cardiac weight, myocyte hypertrophy, fibrosis, or weight-to-dry weight ratio. Deferasirox treatment reduced liver iron content 51%. Deferiprone produced comparable reductions in cardiac iron content (18.6% reduction). Deferiprone-treated hearts had greater mass (16.5% increase) and increased myocyte hypertrophy. Deferiprone decreased liver iron content 24.9% but was associated with an increase in liver weight and water content.
Deferasirox and deferiprone were equally effective in removing stored cardiac iron in a gerbil animal model, but deferasirox removed more hepatic iron for a given cardiac iron burden.
Due to the limited data available in literature, the aim of this multi-centre study was to prospectively compare in thalassemia major (TM) patients the efficacy of combined deferiprone (DFP) and deferoxamine (DFO) regimen versus either DFP and DFO in monotherapy by cardiovascular magnetic resonance (CMR) over a follow up of 18 months.
Among the first 1135 TM patients in the MIOT (Myocardial Iron Overload in Thalassemia) network, we evaluated those who had received either combined regimen (DFO + DFP, N=51) or DFP (N=39) and DFO (N=74) monotherapies between the two CMR scans. Iron overload was measured by T2* multiecho technique. Biventricular function parameters were quantitatively evaluated by cine images.
The percentage of patients that maintained a normal global heart T2* value was comparable between DFP+DFO versus both monotherapy groups. Among the patients with myocardial iron overload at baseline, the changes in the global heart T2* and in biventricular function were not significantly different in DFP+DFO compared with the DFP group. The improvement in the global heart T2* was significantly higher in the DFP+DFO than the DFO group, without a difference in biventricular function. Among the patients with hepatic iron at baseline, the decrease in liver iron concentration values was significantly higher with combination therapy than with either monotherapy group.
In TM patients at the dosages used in the real world, the combined DFP+DFO regimen was more effective in removing cardiac iron than DFO, and was superior in clearing hepatic iron than either DFO or DFP monotherapy. Combined therapy did not show an additional effect on heart function over DFP.
Thalassemia; Chelation therapy; Cardiovascular magnetic resonance
The prognosis of acute myeloid leukemia (AML) in elderly (≥65 years) patients is poor and treatment remains non-consensual especially for those who are not eligible for intensive therapies. Our group has shown that in vitro the iron chelator deferasirox (DFX) synergizes with vitamin D (VD) to promote monocyte differentiation in primary AML cells. Herein, we present results from a retrospective case-control study in which the association of DFX (1–2 g/d) and 25-hydroxycholecalciferol (100,000 IU/week) (DFX/VD) was proposed to patients following demethylating agents failure. Median survival of patients treated with DFX/VD combination (n = 17) was significantly increased in comparison with matched patients receiving best supportive care (BSC) alone (n = 13) (10.4 versus 4 months respectively). In addition, the only factor associated to an increased overall survival in DFX/VD-treated patients was serum VD levels. We conclude that DFX/VD treatment correlated with increased overall survival of AML patients in this retrospective cohort of elderly patients.
Despite the availability of deferoxamine chelation therapy for more than 20 years, iron cardiomyopathy remains the leading cause of death in thalassemia major patients. Effective chelation of cardiac iron is difficult; cardiac iron stores respond more slowly to chelation therapy and require a constant gradient of labile iron species between serum and myocytes. We have previously demonstrated the efficacy of once-daily deferasirox in removing previously stored cardiac iron in the gerbil, but changes in cardiac iron were relatively modest compared with hepatic iron. We postulated that daily divided dosing, by sustaining a longer labile iron gradient from myocytes to serum, would produce better cardiac iron chelation than a comparable daily dose.
Twenty-four 8- to 10-week-old female gerbils underwent iron dextran—loading for 10 weeks, followed by a 1-week iron equilibration period. Animals were divided into three treatment groups of eight animals each and were treated with deferasirox 100 mg/kg/day as a single dose, deferasirox 100 mg/kg/day daily divided dose, or sham chelation for a total of 12 weeks. Following euthanasia, organs were harvested for quantitative iron and tissue histology.
Hepatic and cardiac iron contents were not statistically different between the daily single-dose and daily divided-dose groups. However, the ratio of cardiac to hepatic iron content was lower in the divided-dose group (0.78% vs 1.11%, p = 0.0007).
Daily divided dosing of deferasirox changes the relative cardiac and liver iron chelation profile compared with daily single dosing, trading improvements in cardiac iron elimination for less-effective hepatic chelation.
Chelating agents remain the mainstay in reducing the iron burden and extending patient survival in homozygous beta-thalassemia but adverse and toxic effects may increase with the institution and long term use of this essential therapy. This study aimed to estimate the incidence of deferasirox (DFX) side effects in patients with thalassemia major or intermedia.
A retrospective study of 72 patients (mean age: 20.3±0.9 yrs; 36 male, 36 female) with thalassemia major or intermedia treated at Sultan Qaboos University Hospital, Oman, was performed to assess the incidence of side effects related to deferasirox over a mean of 16.7 month follow-up period.
Six patients experienced rashes and 6 had gastro-intestinal upset. DFX was discontinued in 18 patients for the following reasons: persistent progressive rise(s) in serum creatinine (7 patients; 40% mean serum creatinine rise from baseline), feeling unwell (2), severe diarrhea (1), pregnancy (1), death unrelated to chelator (2) and rise in serum transaminases (2). Three patients were reverted to desferoxamine and deferiprone combination therapy as DFX was no longer biochemically effective after 18 months of therapy. There was no correlation between baseline serum ferritin and serum creatinine or a rise in serum creatinine. Cardiac MRI T2* did not change with DFX therapy. However, there was an improvement in liver MRI T2* (p=0.013).
Renal side effects related to deferasirox appear to be higher than those reported in published clinical trials. Further larger studies are required to confirm these findings.
Chelator; Kidney function; Thalassemia; Toxicity
Many Korean patients with transfusion-induced iron overload experience serious clinical sequelae, including organ damage, and require lifelong chelation therapy. However, due to a lack of compliance and/or unavailability of an appropriate chelator, most patients have not been treated effectively. Deferasirox (DFX), a once-daily oral iron chelator for both adult and pediatric patients with transfusion-induced iron overload, is now available in Korea. The effectiveness of deferasirox in reducing or maintaining body iron has been demonstrated in many studies of patients with a variety of transfusion-induced anemias such as myelodysplastic syndromes, aplastic anemia, and other chronic anemias. The recommended initial daily dose of DFX is 20 mg/kg body weight, taken on an empty stomach at least 30 min before food and serum ferritin levels should be maintained below 1000 ng/mL. To optimize the management of transfusion-induced iron overload, the Korean Society of Hematology Aplastic Anemia Working Party (KSHAAWP) reviewed the general consensus on iron overload and the Korean data on the clinical benefits of iron chelation therapy, and developed a Korean guideline for the treatment of iron overload.
Korean Guideline; Iron Overload; Deferasirox
Recent developments in the understanding of the molecular control of iron homeostasis provided novel
insights into the mechanisms responsible for normal iron balance. However in chronic anemias associated
with iron overload, such mechanisms are no longer sufficient to offer protection from iron toxicity, and iron
chelating therapy is the only method available for preventing early death caused mainly by myocardial and
hepatic damage. Today, long-term deferoxamine (DFO) therapy is an integral part of the management of
thalassemia and other transfusion-dependent anemias, with a major impact on well-being and survival.
However, the high cost and rigorous requirements of DFO therapy, and the significant toxicity of deferiprone
underline the need for the continued development of new and improved orally effective iron chelators.
Within recent years more than one thousand candidate compounds have been screened in animal models. The
most outstanding of these compounds include deferiprone (L1); pyridoxal isonicotinoyl hydrazone (PIH) and;
bishydroxy- phenyl thiazole. Deferiprone has been used extensively as a substitute for DFO in clinical trials
involving hundreds of patients. However, L1 treatment alone fails to achieve a negative iron balance in a
substantial proportion of subjects. Deferiprone is less effective than DFO and its potential hepatotoxicity is
an issue of current controversy. A new orally effective iron chelator should not necessarily be regarded as
one displacing the presently accepted and highly effective parenteral drug DFO. Rather, it could be employed
to extend the scope of iron chelating strategies in a manner analogous with the combined use of medications
in the management of other conditions such as hypertension or diabetes. Coadministration or alternating use
of DFO and a suitable oral chelator may allow a decrease in dosage of both drugs and improve compliance
by decreasing the demand on tedious parenteral drug administration. Combined use of DFO and L1 has
already been shown to result in successful depletion of iron stores in patients previously failing to respond to single drug therapy, and to lead to improved compliance with treatment. It may also result in a “shuttle effect” between weak intracellular chelators and powerful extracellular chelators or exploit the entero-hepatic cycle to promote fecal iron excretion. All of these innovative ways of chelator usage are now awaiting
evaluation in experimental models and in the clinical setting.
Transfusional hemosiderosis is a frequent complication in patients with transfusion dependent chronic diseases such as thalassemias and severe type of sickle cell diseases. As there are no physiological mechanisms to excrete the iron contained in transfused red cells (1 unit of blood contains approximately 200 mg of iron) the excess of iron is stored in various organs. Cardiomyopathy is the most severe complication covering more than 70% of the causes of death of thalassemic patients. Although the current reference standard iron chelator deferoxamine (DFO) has been used clinically for over four decades, its effectiveness is limited by a demanding therapeutic regimen that leads to poor compliance. Despite poor compliance, because of the inconvenience of subcutaneous infusion, DFO improved considerably the survival and quality of life of patients with thalassemia. Deferiprone since 1998 and Deferasirox since 2005 were licensed for clinical use. The oral chelators have a better compliance because of oral use, a comparable efficacy to DFO in iron excretion and probably a better penetration to myocardial cells. Considerable increase in iron excretion was documented with combination therapy of DFO and Deferiprone. The proper use of the three chelators will improve the prevention and treatment of iron overload, it will reduce complications, and improve survival and quality of life of transfused patients.
The iron-chelating drug deferoxamine (DFO) has been shown to be active in animal models of Pneumocystis carinii pneumonia (PCP), with effective daily intraperitoneal bolus dosages being 400 and 1,000 mg of DFO mesylate kg of body weight-1 in mouse and rat models, respectively. Continuous infusion produced a moderately improved response in a rat model. The data reported here demonstrate that the response achieved by continuous infusion of 195 and 335 mg of DFO mesylate kg-1 day-1 in the rat model is associated with mean concentrations in plasma of 1.3 and 2.5 micrograms of DFO ml-1 and mean concentrations in lung tissue of 4.9 and 6.0 micrograms of DFO g of lung tissue-1, respectively. Since current clinical use of DFO mesylate for the treatment of iron overload produces higher concentrations in the plasma of patients, DFO may prove to be a useful anti-PCP treatment. The 2.4- to 3.8-fold higher DFO concentration observed in lung tissue compared with that observed in plasma may be important in the response of PCP to DFO.
Background and Purpose
Intraventricular extension of hemorrhage is a predictor of poor outcome in intracerebral hemorrhage (ICH) and iron overload contributes to brain injury after ICH. The current study investigated the role of iron in ventricular dilatation and neuronal death in a rat model of intraventricular hemorrhage (IVH).
There were two parts in this study. First, male Sprague-Dawley rats had a 200-μl injection of either autologous blood or saline into the right lateral ventricle and were euthanized at different time points. Rats had magnetic resonance imaging and brains were used for Western blot analysis, immunohistochemistry, histology and brain tissue non-heme iron measurements. Second, rats had IVH and were treated with deferoxamine (DFX) or vehicle, and rats were euthanized 4 weeks later for brain tissue loss and lateral ventricle size measurements.
IVH resulted in brain iron accumulation, bilateral enlargement of the lateral ventricles and hippocampal brain tissue loss. Iron accumulation was associated with upregulation of heme oxygenase-1 and ferritin. Systemic DFX treatment reduced IVH-induced ventricular enlargement (e.g. day 28: 32.7±10.6 vs. 43.8±9.7 mm3 in vehicle-treated group, n=8–9, p<0.05) and hippocampal brain tissue loss (hippocampal volume: 89.0±2.7 vs. 85.2±4.1 mm3 in the vehicle-treated group, p<0.05).
Iron has a role in brain injury following IVH. DFX may be a therapy for patients with IVH or intraventricular extension after ICH.
intraventricular hemorrhage; deferoxamine; hydrocephalus; iron
MRI is gaining increasing importance for the noninvasive quantification of organ iron burden. Since transverse relaxation rates depend on iron distribution as well as iron concentration, physiologic and pharmacologic processes that alter iron distribution could change MRI calibration curves. This paper compares the effect of three iron chelators, deferoxamine, deferiprone, and deferasirox on R1 and R2 calibration curves according to two iron loading and chelation strategies. 33 Mongolian gerbils underwent iron loading (iron dextran 500 mg/kg/wk) for 3 weeks followed by 4 weeks of chelation. An additional 56 animals received less aggressive loading (200 mg/kg/week) for 10 weeks, followed by 12 weeks of chelation. R1 and R2 calibration curves were compared to results from 23 iron-loaded animals that had not received chelation. Acute iron loading and chelation biased R1 and R2 from the unchelated reference calibration curves but chelator-specific changes were not observed, suggesting physiologic rather than pharmacologic differences in iron distribution. Long term chelation deferiprone treatment increased liver R1 50% (p<0.01), while long term deferasirox lowered liver R2 30.9% (p<0.0001). The relationship between R1 and R2 and organ iron concentration may depend upon the acuity of iron loading and unloading as well as the iron chelator administered.
Iron accumulates in the brain and contributes to brain injury after intracerebral hemorrhage (ICH). The c-Jun-N-terminal kinase (JNK) signaling pathway mediates cell death after ischemic stroke, however, the involvement of JNK in ICH is not well known. This study investigated whether the JNK signaling pathway is activated by iron after ICH. Male Sprague-Dawley rats received an infusion of autologous whole blood (as a model of ICH) or ferrous iron into the right basal ganglia and control rats had an infusion of saline. Some ICH rats were treated with either deferoxamine (DFX), an iron chelator, or vehicle. Activation of JNK was measured by Western blot analysis and immunohistochemistry. Free iron in cerebrospinal fluid (CSF) and behavioral outcomes following ICH were also examined. We found that activated-JNK in the brain were increased after ICH, and an intracerebral infusion of ferrous iron also upregulated brain activated-JNK. Free iron accumulated in CSF and Systemic administration of DFX after ICH reduces free iron contents in CSF, suppresses JNK activation and improves ICH-induced neurological deficits. Our results demonstrated that the JNK signaling pathway is activated after ICH and iron may contribute to this activation. DFX reduces free iron levels and attenuates activation of JNK suggesting iron chelation may be useful therapy for ICH patients.
cerebral hemorrhage; c-Jun-N-terminal kinase; deferoxamine; iron
Established heart failure in thalassaemia major has a poor prognosis and optimal management remains unclear.
A 1 year prospective study comparing deferoxamine (DFO) monotherapy or when combined with deferiprone (DFP) for patients with left ventricular ejection fraction (LVEF) <56% was conducted by the Thalassemia Clinical Research Network (TCRN). All patients received DFO at 50–60 mg/kg 12–24 hr/day sc or iv 7 times weekly, combined with either DFP 75 at mg/kg/day (combination arm) or placebo (DFO monotherapy arm). The primary endpoint was the change in LVEF by CMR.
Improvement in LVEF was significant in both study arms at 6 and 12 months (p = 0.04), normalizing ventricular function in 9/16 evaluable patients. With combination therapy, the LVEF increased from 49.9% to 55.2% (+5.3% p = 0.04; n = 10) at 6 months and to 58.3% at 12 months (+8.4% p = 0.04; n = 7). With DFO monotherapy, the LVEF increased from 52.8% to 55.7% (+2.9% p = 0.04; n = 6) at 6 months and to 56.9% at 12 months (+4.1% p = 0.04; n = 4). The LVEF trend did not reach statistical difference between study arms (p = 0.89). In 2 patients on DFO monotherapy during the study and in 1 patient on combined therapy during follow up, heart failure deteriorated fatally. The study was originally powered for 86 participants to determine a 5% difference in LVEF improvement between treatments. The study was prematurely terminated due to slow recruitment and with the achieved sample size of 20 patients there was 80% power to detect an 8.6% difference in EF, which was not demonstrated. Myocardial T2* improved in both arms (combination +1.9 ± 1.6 ms p = 0.04; and DFO monotherapy +1.9 ± 1.4 ms p = 0.04), but with no significant difference between treatments (p = 0.65). Liver iron (p = 0.03) and ferritin (p < 0.001) both decreased significantly in only the combination group.
Both treatments significantly improved LVEF and myocardial T2*. Although this is the largest and only randomized study in patients with LV decompensation, further prospective evaluation is needed to identify optimal chelation management in these high-risk patients.
Thalassemia; Heart failure; Deferoxamine; Deferiprone; Combination
This study investigates the pathophysiology of mucormycosis caused by Rhizopus, which has been reported in 46 dialysis patients, while treated with deferoxamine (DFO). This drug aggravates mucormycosis, which we experimentally induced in guinea pigs and which lead to a shortened animal survival (P < or = 0.01). The drug's effect on Rhizopus is not mediated through the polymorphonuclear cells. Fe.DFO, the iron chelate of DFO, abolishes the fungistatic effect of serum on Rhizopus and increases the in vitro growth of the fungus (P < or = 0.0001). This effect is present at Fe.DFO concentrations > or = 0.01 microM, at which fungal uptake of radioiron from 55Fe.DFO is observed. A 1,000-fold higher concentration of iron citrate is required to achieve a similar rate of radioiron uptake and of in vitro growth stimulation as observed with Fe.DFO. These in vitro effects of Fe.DFO (1 microM) in serum on radioiron uptake and on growth stimulation are more striking for Rhizopus than for Aspergillus fumigatus and are practically absent for Candida albicans. For these three fungal species, the rates of radioiron uptake from 55Fe.DFO and of growth stimulation in the presence of Fe.DFO in serum are directly related (r = 0.886). These results underscore the major role of Fe.DFO in the pathogenesis of DFO-related mucormycosis. Pharmacokinetic changes in uremia lead to a prolonged accumulation of Fe.DFO after DFO administration, which helps explain the increased sensitivity of dialysis patients to DFO-related mucormycosis.
Medically based efforts and alternative treatment strategies to prevent or remediate the corrosive effects of radiotherapy on pathologic fracture healing have failed to produce clear and convincing evidence of success. Establishing an effective pharmacologic option to prevent or treat the development of non-unions in this setting could have immense therapeutic potential. Experimental studies have shown that Deferoxamine (DFO), an iron- chelating agent, bolsters vascularity and subsequently enhances normal fracture healing when injected locally into a fracture callus in long bone animal models. Since radiotherapy is known to impede angiogenesis, we hypothesized that the pharmacologic addition of DFO would serve to mitigate the effects of radiotherapy on new vessel formation in vitro and in vivo.
Materials and Methods
In vitro investigation of angiogenesis was conducted utilizing HUVEC cells in Matrigel. Endothelial tubule formation assays were divided into four groups: Control, Radiated, Radiated + Low Dose DFO and Radiated + High Dose DFO. Tubule formation was quantified microscopically and video recorded for the four groups simultaneously during the experiment. In vivo, three groups of Sprague–Dawley rats underwent external fixator placement and fracture osteotomy of the left mandible. Two groups received pre-operative fractionated radiotherapy, and one of these groups was treated with DFO after fracture repair. After 40 days, the animals were perfused and imaged with micro-CT to calculate vascular radiomorphometrics.
In vitro, endothelial tubule formation assays demonstrated that DFO mitigated the deleterious effects of radiation on angiogenesis. Further, high-dose DFO cultures appeared to organize within 2 hours of incubation and achieved a robust network that was visibly superior to all other experimental groups in an accelerated fashion. In vivo, animals subjected to a human equivalent dose of radiotherapy (HEDR) and left mandibular fracture demonstrated quantifiably diminished μCT metrics of vascular density, as well as a 75% incidence of associated non-unions. The addition of DFO in this setting markedly improved vascularity as demonstrated with 3D angiographic modeling. In addition, we observed an increased incidence of bony unions in the DFO treated group when compared to radiated fractures without treatment (67% vs. 25% respectively).
Our data suggest that selectively targeting angiogenesis with localized DFO injections is sufficient to remediate the associated severe vascular diminution resulting from a HEDR. Perhaps the most consequential and clinically relevant finding was the ability to reduce the incidence of non-unions in a model where fracture healing was not routinely observed.
Osteoradionecrosis; Deferoxamine; Pathologic Fracture; Angiogenesis; Non-union; Radiotherapy
The purpose of this study was to investigate hemoglobin and iron handling after subarachnoid hemorrhage (SAH), examine the relationship between iron and neuro-glial cell changes and determine whether deferoxamine (DFX) can reduce SAH-induced injury. SAH was induced in Sprague-Dawley rats (n=110) using an endovascular perforation technique. Animals were treated with DFX (100 mg/kg) or vehicle 2 h and 6 h after SAH induction followed by every 12 h for 3 days. Rats were sacrificed at 6 h, Day 1 and 3 to determine non-heme iron and examine iron-handling proteins using Western-blot and immunohistochemistry. 8-Hydroxyl-2′-deoxyguanosine and TUNEL staining were performed to assess oxidative DNA damage and apoptotic neuronal cell death. After SAH, marked HO-1 upregulation at Day 3 (P<0.01) was accompanied by elevated non-heme iron (P<0.01), transferrin (P<0.01), transferrin receptor (P<0.05) and ferritin levels (P<0.01). DFX treatment reduced SAH-induced mortality (12% vs. 29%, P<0.05), brain non-heme iron concentration, iron-handling protein expression, oxidative stress and neuronal cell death at Day 3 (P<0.01) following SAH. These results suggest that iron overload in the acute phase of SAH causes oxidative injury leading to neuronal cell death. Deferoxamine effectively reduced oxidative stress and neuronal cell death, and may be a potential therapeutic agent for SAH.
Deferoxamine; Hemoglobin; Iron; Oxidative injury; Subarachnoid hemorrhage
Renal fibrosis plays an important role in the onset and progression of chronic kidney diseases (CKD). Although several mechanisms underlying renal fibrosis and candidate drugs for its treatment have been identified, the effect of iron chelator on renal fibrosis remains unclear. In the present study, we examined the effect of an iron chelator, deferoxamine (DFO), on renal fibrosis in mice with surgically induced unilateral ureter obstruction (UUO). Mice were divided into 4 groups: UUO with vehicle, UUO with DFO, sham with vehicle, and sham with DFO. One week after surgery, augmented renal tubulointerstitial fibrosis and the expression of collagen I, III, and IV increased in mice with UUO; these changes were suppressed by DFO treatment. Similarly, UUO-induced macrophage infiltration of renal interstitial tubules was reduced in UUO mice treated with DFO. UUO-induced expression of inflammatory cytokines and extracellular matrix proteins was abrogated by DFO treatment. DFO inhibited the activation of the transforming growth factor-β1 (TGF-β1)-Smad3 pathway in UUO mice. UUO-induced NADPH oxidase activity and p22phox expression were attenuated by DFO. In the kidneys of UUO mice, divalent metal transporter 1, ferroportin, and ferritin expression was higher and transferrin receptor expression was lower than in sham-operated mice. Increased renal iron content was observed in UUO mice, which was reduced by DFO treatment. These results suggest that iron reduction by DFO prevents renal tubulointerstitial fibrosis by regulating TGF-β-Smad signaling, oxidative stress, and inflammatory responses.
Intracerebral hemorrhage (ICH) is a devastating form of stroke. In this study, we examined the efficacy of deferoxamine (DFX), an iron chelator, after collagenase-induced ICH in 12-month-old mice. Intracerebral hemorrhage was induced by intrastriatal injection of collagenase. Deferoxamine (200 mg/kg, intraperitoneal) or vehicle was administrated 6 hours after ICH and then every 12 hours for up to 3 days. Neurologic deficits were examined on days 1 and 3 after ICH. Mice were killed after 1 or 3 days of DFX treatment for examination of iron deposition, neuronal death, oxidative stress, microglia/astrocyte activation, neutrophil infiltration, brain injury volume, and brain edema and swelling. Collagenase-induced ICH resulted in iron overload in the perihematomal region on day 3. Systemic administration of DFX decreased iron accumulation and neuronal death, attenuated production of reactive oxygen species, and reduced microglial activation and neutrophil infiltration without affecting astrocytes. Although DFX did not reduce brain injury volume, edema, or swelling, it improved neurologic function. Results of our study indicate that iron toxicity contributes to collagenase-induced hemorrhagic brain injury and that reducing iron accumulation can reduce neuronal death and modestly improve functional outcome after ICH in mice.
deferoxamine; inflammation; iron; neuronal death; reactive oxygen species; stroke
Hemoglobin degradation products, in particular iron, have been implicated in secondary neuronal injury following intracerebral hemorrhage (ICH). The iron chelator Deferoxamine Mesylate (DFO) exerts diverse neuroprotective effects, reduces perihematoma edema (PHE) and neuronal damage, and improves functional recovery after experimental ICH. We hypothesize that treatment with DFO could minimize neuronal injury and improve outcome in ICH patients. As a prelude to test this hypothesis, we conducted a Phase I, open-label study to determine the tolerability, safety, and maximum tolerated dose (MTD) of DFO in patients with ICH. Intravenous infusions of DFO in doses up to 62 mg/kg/day (up to a maximum of 6000 mg/day) were well-tolerated and did not seem to increase serious adverse events (SAEs) or mortality. We have initiated a multi-center, double-blind, randomized, placebo-controlled, Phase II clinical trial (High Dose Deferoxamine [HI-DEF] in Intracerebral Hemorrhage) to determine if it is futile to move DFO forward to Phase III efficacy evaluation.
We will randomize 324 subjects with spontaneous ICH to either DFO at 62 mg/kg/day (up to a maximum daily dose of 6000 mg/day) or saline placebo, given by intravenous infusion for 5 consecutive days. Treatment will be initiated within 24 hours after ICH symptom onset. All subjects will be followed for 3 months and will receive standard of care therapy while participating in the study. At 3 months, the proportion of DFO-treated subjects with a good clinical outcome, assessed by modified Rankin Scale, will be compared to the placebo proportion in a futility analysis.
The Hi-Def trial is expected to advance our understanding of the pathopgysiology of secondary neuronal injury in ICH and will provide a crucial “Go/No Go” signal as to whether a Phase III trial to investigate the efficacy of DFO is warranted.
Intracerebral hemorrhage; Deferoxamine; Clinical trial; Futility design
To date, there is a lack of long-term safety and efficacy data for iron chelation therapy in transfusion-dependent patients with sickle cell disease (SCD). To evaluate the long-term safety and efficacy of deferasirox (a once-daily oral iron chelator), patients with SCD completing a 1-year, Phase II, randomized, deferoxamine (DFO)-controlled study entered a 4-year extension, continuing to receive deferasirox, or switching from DFO to deferasirox. Average actual deferasirox dose was 19·4 ± 6·3 mg/kg per d. Of 185 patients who received at least one deferasirox dose, 33·5% completed the 5-year study. The most common reasons for discontinuation were withdrawal of consent (23·8%), lost to follow-up (9·2%) and adverse events (AEs) (7·6%). Investigator-assessed drug-related AEs were predominantly gastrointestinal [including nausea (14·6%), diarrhoea (10·8%)], mild-to-moderate and transient in nature. Creatinine clearance remained within the normal range throughout the study. Despite conservative initial dosing, serum ferritin levels in patients with ≥4 years deferasirox exposure significantly decreased by −591 μg/l (95% confidence intervals, −1411, −280 μg/l; P=0·027; n=67). Long-term deferasirox treatment for up to 5 years had a clinically acceptable safety profile, including maintenance of normal renal function, in patients with SCD. Iron burden was substantially reduced with appropriate dosing in patients treated for at least 4 years.
deferasirox; Exjade; oral iron chelator; sickle cell disease; iron overload