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
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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.
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
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.
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
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
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.
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
Treatment of iron overload using deferoxamine (DFO) is associated with significant deficits in patients' health-related quality of life (HRQOL) and low treatment satisfaction. The current article presents patient-reported HRQOL, satisfaction, adherence, and persistence data from β-thalassemia (n = 274) and myelodysplastic syndrome (MDS) patients (n = 168) patients participating in the Evaluation of Patients' Iron Chelation with Exjade (EPIC) study (NCT00171821); a large-scale 1-year, phase IIIb study investigating the efficacy and safety of the once-daily oral iron chelator, deferasirox. HRQOL and satisfaction, adherence, and persistence to iron chelation therapy (ICT) data were collected at baseline and end of study using the Medical Outcomes Short-Form 36-item Health Survey (SF-36v2) and the Satisfaction with ICT Questionnaire (SICT). Compared to age-matched norms, β-thalassemia and MDS patients reported lower SF-36 domain scores at baseline. Low levels of treatment satisfaction, adherence, and persistence were also observed. HRQOL improved following treatment with deferasirox, particularly among β-thalassemia patients. Furthermore, patients reported high levels of satisfaction with deferasirox at end of study and greater ICT adherence, and persistence. Findings suggest deferasirox improves HRQOL, treatment satisfaction, adherence, and persistence with ICT in β-thalassemia and MDS patients. Improving such outcomes is an important long-term goal for patients with iron overload.
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.
Emerging clinical data indicate that transfusion-dependent patients with bone marrow-failure syndromes (BMFS) are at risk of the consequences of iron overload, including progressive damage to hepatic, endocrine, and cardiac organs. Despite the availability of deferoxamine (DFO) in Korea since 1998, data from patients with myelodysplastic syndromes, aplastic anemia, and other BMFS show significant iron overload and damage to the heart and liver. The recent introduction of deferasirox, a once-daily, oral iron chelator, may improve the availability of iron chelation therapy to iron-overloaded patients, and improve compliance in patients who may otherwise find adherence to the DFO regimen difficult.
Aplastic anemia; Myelodysplastic syndromes; Iron overload; Deferasirox
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 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.
Our previous study showed a reduction in serum ferritin of β-thalassemia patients on hydroxyurea therapy. Here we aimed to evaluate the efficacy of hydroxyurea alone and in combination with most widely used iron chelators like deferiprone and deferasirox for reducing iron from experimentally iron overloaded mice. 70 BALB/c mice received intraperitonial injections of iron-sucrose. The mice were then divided into 8 groups and were orally given hydroxyurea, deferiprone or deferasirox alone and their combinations for 4 months. CBC, serum-ferritin, TBARS, sTfr and hepcidin were evaluated before and after iron overload and subsequently after 4 months of drug therapy. All animals were then killed. Iron staining of the heart and liver tissue was done using Perl’s Prussian Blue stain. Dry weight of iron in the heart and liver was determined by atomic absorption spectrometry. Increased serum-ferritin, TBARS, hepcidin and dry weight of iron in the liver and heart showed a significant reduction in groups treated with iron chelators with maximum reduction in the group treated with a combination of deferiprone, deferasirox and hydroxyurea. Thus hydroxyurea proves its role in reducing iron from iron overloaded mice. The iron chelating effect of these drugs can also be increased if given in combination.
In iron overload conditions, plasma contains non-transferrin bound iron species, collectively referred to as plasma NTBI. These include iron-citrate species, some of which are protein bound. Because NTBI is taken into tissues susceptible to iron loading, its removal by chelation is desirable but only partial using standard deferoxamine (DFO) therapy. Speciation plots suggest that, at clinically achievable concentrations, deferiprone (DFP) will shuttle iron onto DFO to form feroxamine (FO), but whether NTBI chelation is enhanced to therapeutically relevant rates is unknown. As FO is highly stable, kinetic measurements of FO formation by HPLC or by stopped-flow spectrometry is achievable. In serum from thalassemia major patients, supplemented with 10µM DFO, FO formation paralleled NTBI removal but never exceeded 50% of potentially available NTBI: approximately one third of NTBI was chelated rapidly but only 15% of the remainder at 20h. Addition of DFP increased the magnitude of the slower component, with increments in FO formation equivalent to complete NTBI removal by 8h. This shuttling effect was absent in serum from healthy control subjects, indicating no transferrin iron removal. Studies with iron-citrate solutions also showed biphasic chelation by DFO, the slow component being accelerated by the addition of DFP, with optimal enhancement at 30µM. Physiological concentrations of albumin also enhanced DFO chelation from iron citrate, and co-addition of DFP further accelerated this effect. We conclude that at clinically relevant concentrations, DFP enhances plasma NTBI chelation with DFO by rapidly accessing and shuttling NTBI fractions that are otherwise only slowly available to DFO.
Deferasirox is a once-daily, oral iron chelator developed for treating transfusional iron overload. Preclinical studies indicated that the kidney was a potential target organ of toxicity. As patients with sickle cell disease often have abnormal baseline renal function, the primary objective of this randomised, open-label, phase II trial was to evaluate the safety and tolerability of deferasirox in comparison with deferoxamine in this population. Assessment of efficacy, as measured by change in liver iron concentration (LIC) using biosusceptometry, was a secondary objective. A total of 195 adult and paediatric patients received deferasirox (n = 132) or deferoxamine (n = 63). Adverse events most commonly associated with deferasirox were mild, including transient nausea, vomiting, diarrhoea, abdominal pain and skin rash. Abnormal laboratory studies with deferasirox were occasionally associated with mild non-progressive increases in serum creatinine and reversible elevations in liver function tests. Discontinuation rates from deferasirox (11·4%) and deferoxamine (11·1%) were similar. Over 1 year, similar dose-dependent LIC reductions were observed with deferasirox and deferoxamine. Once-daily oral deferasirox has acceptable tolerability and appears to have similar efficacy to deferoxamine in reducing iron burden in transfused patients with sickle cell disease.
deferasirox; ICL670; Exjade; sickle cell disease; iron overload
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.
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
Many patients with transfusional iron overload are at risk for progressive organ dysfunction and early death and poor compliance with older chelation therapies is believed to be a major contributing factor. Phase II/III studies have shown that oral deferasirox 20–30 mg/kg/d reduces iron burden, depending on transfusional iron intake.
The prospective, open-label, 1-yr ESCALATOR study in the Middle East was designed to evaluate once-daily deferasirox in patients ≥2 yr with β-thalassaemia major and iron overload who were previously chelated with deferoxamine and/or deferiprone. Most patients began treatment with deferasirox 20 mg/kg/d; doses were adjusted in response to markers of over- or under-chelation. The primary endpoint was treatment success, defined as a reduction in liver iron concentration (LIC) of ≥3 mg Fe/g dry weight (dw) if baseline LIC was ≥10 mg Fe/g dw, or final LIC of 1–7 mg Fe/g dw for patients with baseline LIC of 2 to <10 mg Fe/g dw.
Overall, 233/237 enrolled patients completed 1 yr’s treatment. Mean baseline LIC was 18.0 ± 9.1 mg Fe/g dw, while median serum ferritin was 3356 ng/mL. After 1 yr’s deferasirox treatment, the intent-to-treat population experienced a significant treatment success rate of 57.0% (P = 0.016) and a mean reduction in LIC of 3.4 mg Fe/g dw. Changes in serum ferritin appeared to parallel dose increases at around 24 wk. Most patients (78.1%) underwent dose increases above 20 mg/kg/d, primarily to 30 mg/kg/d. Drug-related adverse events were mostly mild to moderate and resolved without discontinuing treatment.
The results of the ESCALATOR study in primarily heavily iron-overloaded patients confirm previous observations in patients with β-thalassaemia, highlighting the importance of timely deferasirox dose adjustments based on serum ferritin levels and transfusional iron intake to ensure patients achieve their therapeutic goal of maintenance or reduction in iron burden.
iron chelation; deferasirox; β-thalassaemia; transfusional iron overload
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
Understanding patients’ views about medication is crucial to maximize adherence. Thalassemia is a congenital blood disorder requiring chronic blood transfusions and daily iron chelation therapy.
The Beliefs in Medicine Questionnaire (BMQ) was used to assess beliefs in chelation in thalassemia patients from North America and London in the Thalassemia Longitudinal Cohort (TLC) of the Thalassemia Clinical Research Network (TCRN). Chelation adherence was based on patient report of doses administered out of those prescribed in the last four weeks.
Of 371 patients (ages 5-58y, mean 24y), 93% were transfused and 92% receiving chelation (26% deferoxamine (DFO; a slow subcutaneous infusion via portable pump), 63% oral, 11% combination). Patients expressed high “necessity” for transfusion (96%), DFO chelation (92%) and oral chelation (89%), with lower “concern” about treatment (48%, 39%, 19% respectively). Concern about oral chelation was significantly lower than that of DFO (p<0.001). Self-reported adherence to chelation was not associated with views about necessity or concerns, but negatively correlated with perceived sensitivity to DFO (Sensitive Soma scale; r=−0.23, p=0.01) and side effects of oral chelation (r=−0.14, p=0.04). High ferritin iron levels, potentially indicating lower adherence, were found in 41% of patients reporting low necessity of oral chelation compared to 24% reporting high necessity (p=0.048). Concerns about treatment were associated with lower quality of life and more symptoms of anxiety and depression.
Despite their requirement for multimodal therapy, thalassemia patients have positive views about medicine, more so than in other disease populations. Patients may benefit from education about the tolerability of chelation and strategies to effectively cope with side effects, both of which might be beneficial in lowering body iron burden.
Thalassemia; Necessity; Concerns; Chelation; Adherence
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.
Background and Purpose
Treatment with the iron chelator, deferoxamine mesylate (DFO), improves neurological recovery in animal models of Intracerebral hemorrhage (ICH). We aimed to evaluate the feasibility, safety, and tolerability of varying dose-tiers of DFO in patients with spontaneous ICH, and to determine the Maximum Tolerated Dose (MTD) to be adopted in future efficacy studies.
A multicenter, phase-I, dose-finding study using the Continual Reassessment Method. DFO was administered by an intravenous infusion for 3 consecutive days, starting within 18 hours of ICH onset. Subjects underwent repeated clinical assessments through 90 days, and CT neuroimaging pre- and post-drug administration.
Twenty subjects were enrolled into 5 dose tiers, starting with 7 mg/kg/day and ending with 62 mg/kg/day as the MTD. Median age was 68 years (range: 50–90); 60% were men; and median GCS and NIHSS scores on admission were 15 (5–15) and 9 (0–39), respectively. ICH location was lobar in 40%, deep in 50%, and brainstem in 10%; intraventricular hemorrhage was present in 15%. DFO was discontinued due to adverse events in 2 subjects (10%). Six subjects (30%) experienced 12 serious adverse events (SAEs), none were drug-related. DFO infusions were associated with mild blood pressure lowering effects. Fifty percent of patients had mRS ≤2 and 39% had mRS 4–6 on day-90; 15% died.
Consecutive daily infusions of DFO after ICH are feasible, well-tolerated, and not associated with excessive SAEs or mortality. Our findings lay the groundwork for future studies to evaluate the efficacy of DFO in ICH.
Deferoxamine Mesylate; Iron; ICH
The iron-chelating drug deferoxamine mesylate (DFO) is active against Pneumocystis carinii in vitro and in rat and mouse models of P. carinii pneumonia. Because DFO has a short half-life, daily divided or continuous dosage was expected to improve the dose response, as is the case with DFO treatment of malaria. Therefore, results of single daily intraperitoneal injections were compared with results of an evenly divided four-times-daily dosage and the efficacy of delivery with implanted infusion pumps. The highest bolus dosage (1,000 mg kg-1 of body weight day-1) was as effective as the standard combination of trimethoprim with sulfamethoxazole. Unexpectedly, very little improvement was observed with the divided or continuous dosage, and several mechanisms that could account for this are discussed.
Although blood transfusions are important for patients with anemia, chronic transfusions inevitably lead to iron overload as humans cannot actively remove excess iron. The cumulative effects of iron overload lead to significant morbidity and mortality, if untreated. Although the current reference standard iron chelator deferoxamine has been used clinically for over four decades, its effectiveness is limited by a demanding therapeutic regimen that leads to poor compliance. Deferasirox (Exjade®, ICL670, Novartis Pharma AG, Basel, Switzerland) is a once-daily, oral iron chelator approved for the treatment of transfusional iron overload in adult and pediatric patients. The efficacy and safety of deferasirox have been established in a comprehensive clinical development program involving patients with various transfusion-dependent anemias. Deferasirox has a dose-dependent effect on iron burden, and is as efficacious as deferoxamine at comparable therapeutic doses. Deferasirox therapy can be tailored to a patient’s needs, as response is related to both dose and iron intake. Since deferasirox has a long half-life and is present in the plasma for 24 hours with once-daily dosing, it is unique in providing constant chelation coverage with a single dose. The availability of this convenient, effective, and well tolerated therapy represents a significant advance in the management of transfusional iron overload.
Exjade; deferasirox; transfusional iron overload; effective