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Background: Established heart failure in thalassaemia major has a poor prognosis and optimal management remains unclear., Methods: 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., Results: 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., Conclusions: 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.

The Thalassemia Clinical Research Network collected adherence information from 79 patients on deferoxamine and 186 on deferasirox from 2007 to 2009. Chelation adherence was defined as percent of doses administered in the last 4 weeks (patient report) out of those prescribed(chart review). Chelation history since 2002 was available for 97 patients currently on deferoxamine and 217 on deferasirox, with crude estimates of adherence from chart review. Self-reported adherence to both deferoxamine and deferasirox were quite high, with slightly higher adherence to the oral chelator (97 vs. 92%). Ninety percent of patients on deferasirox reported at least 90% adherence, compared with 75% of patients on deferoxamine. Adherence to both chelators was highest in children, followed by adolescents and older adults.Predictors of lower deferoxamine adherence were smoking in the past year, problems sticking themselves (adults only), problems wearing their pump, and fewer transfusions in the past year. Predictors of lower deferasirox adherence were bodily pain and depression. Switching chelators resulted in increased adherence, regardless of the direction of the switch, although switching from deferoxamine to deferasirox was far more common. As adherence to deferoxamine is higher than previously reported, it appears beneficial for patients to have a choice in chelators.

Background: We assessed whether oxidant-stress and inflammation in beta-thalassemia could be controlled by the novel oral iron chelator deferasirox as effectively as by deferoxamine., Design and Methods: Forty-nine subjects were enrolled from seven sites and studied at baseline, and after 1, 6, and 12 months of therapy. Malondialdehyde, protein carbonyls, vitamins E and C, total non-transferrin bound iron, transferrin saturation, C-reactive protein, cytokines, serum ferritin concentration and liver iron concentration were measured., Results: Liver iron concentration and ferritin declined significantly in both treatment groups during the study. This paralleled a significant decline in the oxidative-stress marker malondialdehyde (deferasirox -22%/year, deferoxamine -28%/year, average decline p=0.006). The rates of decline did not differ between treatment groups. Malondialdehyde was higher in both treatment groups than in a group of 30 non-thalassemic controls (p < 0.001). The inflammatory marker high-sensitivity C-reactive protein decreased significantly only in the group receiving deferasirox (deferasirox -51%/year, deferoxamine +8.5%/year, p = 0.02). This result was confounded by a chance difference in the level of high-sensitivity C-reactive protein between the two groups at baseline, but analyses controlling for this difference suggested an equally large treatment effect., Conclusions: Iron chelation therapy with deferoxamine or with deferasirox was equally effective in decreasing iron burden and malondialdehyde. The possible differential effect of the two chelators on inflammation warrants further investigation.

Objectives/methods: This 1-yr prospective phase II trial evaluated the efficacy of deferasirox in regularly transfused patients aged 3-81 yrs with myelodysplastic syndromes (MDS; n = 47), Diamond-Blackfan anaemia (DBA; n = 30), other rare anaemias (n = 22) or beta-thalassaemia (n = 85). Dosage was determined by baseline liver iron concentration (LIC)., Results: In patients with baseline LIC > or = 7 mg Fe/g dry weight, deferasirox initiated at 20 or 30 mg/kg/d produced statistically significant decreases in LIC (P < 0.001); these decreases were greatest in MDS and least in DBA. As chelation efficiency and iron excretion did not differ significantly between disease groups, the differences in LIC changes are consistent with mean transfusional iron intake (least in MDS: 0.28 +/- 0.14 mg/kg/d; greatest in DBA: 0.4 +/- 0.11 mg/kg/d). Overall, LIC changes were dependent on dose (P < 0.001) and transfusional iron intake (P < 0.01), but not statistically different between disease groups. Changes in serum ferritin and LIC were correlated irrespective of disease group (r = 0.59), supporting the potential use of serum ferritin for monitoring deferasirox therapy. Deferasirox had a safety profile compatible with long-term use. There were no disease-specific safety/tolerability effects: the most common adverse events were gastrointestinal disturbances, skin rash and non-progressive serum creatinine increases., Conclusions: Deferasirox is effective for reducing iron burden with a defined, clinically manageable safety profile in patients with various transfusion-dependent anaemias. There were no disease-specific adverse events. Once differences in transfusional iron intake are accounted for, dose-dependent changes in LIC or serum ferritin are similar in MDS and other disease groups.

Deferasirox (ICL670) is a once-daily oral iron chelator developed for the treatment of chronic iron overload from blood transfusions. A comparative phase 3 trial was conducted to demonstrate the efficacy of deferasirox in regularly transfused patients with beta-thalassemia aged 2 years or older. Patients were randomized and received treatment with deferasirox (n = 296) or deferoxamine (n = 290), with dosing of each according to baseline liver iron concentration (LIC). The primary endpoint was maintenance or reduction of LIC; secondary endpoints included safety and tolerability, change in serum ferritin level, and net body iron balance. In both arms, patients with LIC values of 7 mg Fe/g dry weight (dw) or higher had significant and similar dose-dependent reductions in LIC and serum ferritin, and effects on net body iron balance. However, the primary endpoint was not met in the overall population, possibly due to the fact that proportionally lower doses of deferasirox relative to deferoxamine were administered to patients with LIC values less than 7 mg Fe/g dw. The most common adverse events included rash, gastrointestinal disturbances, and mild nonprogressive increases in serum creatinine. No agranulocytosis, arthropathy, or growth failure was associated with deferasirox administration. Deferasirox is a promising once-daily oral therapy for the treatment of transfusional iron overload.

Transfusion therapy for inherited anemias and acquired refractory anemias both improves the quality of life and prolongs survival. A consequence of chronic transfusion therapy is secondary iron overload, which adversely affects the function of the heart, the liver and other organs. This session will review the use of iron chelating agents in the management of transfusion-induced secondary iron overload. In Section I Dr. John Porter describes techniques for the administration of deferoxamine that exploit the pharmacokinetic properties of the drug and minimize potential toxic side effects. The experience with chelation therapy in patients with thalassemia and sickle cell disease will be reviewed and guidelines will be suggested for chelation therapy of chronically transfused adults with refractory anemias. In Section II Dr. Nancy Olivieri examines the clinical consequences of transfusion-induced secondary iron overload and suggests criteria useful in determining the optimal timing of the initiation of chelation therapy. Finally, Dr. Olivieri discusses the clinical trials evaluating orally administered iron chelators.

Whereas hemoglobin (Hb) E-beta thalassemia is recognized as probably the most common serious hemoglobinopathy worldwide, its natural history remains poorly defined. The interaction of hemoglobin E and beta-thalassemia result in a wide spectrum of clinical disorders, some indistinguishable from thalassemia major and some milder and not transfusion-dependent. Partially as a result of this wide range of phenotypes, clear guidelines for approaches to transfusion and to iron-chelating therapy for patients with Hb E-beta thalassemia have not been developed. By contrast, data that have accumulated during the past 10 years in patients with beta-thalassemia permit a quantitative approach to the management of iron overload and provide guidelines for the control of body iron burden in individual patients treated with iron-chelating therapy. These guidelines may be applicable to patients with Hb E-beta thalassemia. Preliminary evidence from our studies of iron loading in affected patients with Hb E-beta thalassemia in Sri Lanka suggest that this disorder may be associated with variable, but accelerated, gastrointestinal iron absorption, and that the iron loading associated with chronic transfusions in patients with Hb E-beta thalassemia is similar to that observed in patients with beta-thalassemia. These data, in the only cohort of patients with Hb E-beta thalassemia to have undergone quantitative assessment of body iron burden, suggest that the principles that guide assessment of iron loading and initiation of chelating therapy in patients with beta-thalassemia may be generally applicable to those with Hb E-beta thalassemia. Further quantitative studies in both nontransfused and transfused patients will be necessary to permit firm conclusions.

Background: Deferiprone is an orally active iron-chelating agent that is being evaluated as a treatment for iron overload in thalassemia major. Studies in an animal model showed that prolonged treatment is associated with a decline in the effectiveness of deferiprone and exacerbation of hepatic fibrosis., Methods: Hepatic iron stores were determined yearly by chemical analysis of liver-biopsy specimens, magnetic susceptometry, or both. Three hepatopathologists who were unaware of the patients' clinical status, the time at which the specimens were obtained, and the iron content of the specimens examined 72 biopsy specimens from 19 patients treated with deferiprone for more than one year. For comparison, 48 liver-biopsy specimens obtained from 20 patients treated with parenteral deferoxamine for more than one year were similarly reviewed., Results: Of the 19 patients treated with deferiprone, 18 had received the drug continuously for a mean (+/-SE) of 4.6+/-0.3 years. At the final analysis, 7 of the 18 had hepatic iron concentrations of at least 80 micromol per gram of liver, wet weight (the value above which there is an increased risk of cardiac disease and early death in patients with thalassemia major). Of 19 patients in whom multiple biopsies were performed over a period of more than one year, 14 could be evaluated for progression of hepatic fibrosis; of the 20 deferoxamine-treated patients, 12 could be evaluated for progression. Five deferiprone-treated patients had progression of fibrosis, as compared with none of those given deferoxamine (P=0.04). By the life-table method, we estimated that the median time to progression of fibrosis was 3.2 years in deferiprone-treated patients. After adjustment for the initial hepatic iron concentration, the estimated odds of progression of fibrosis increased by a factor of 5.8 (95 percent confidence interval, 1.1 to 29.6) with each additional year of deferiprone treatment., Conclusions: Deferiprone does not adequately control body iron burden in patients with thalassemia and may worsen hepatic fibrosis.

Deferoxamine is the currently available agent for the iron-chelation therapy required by Cooley's anemia patients. The difficulties associated with parenteral administration have mandated a search for alternative therapies, especially orally active iron chelators, to remove excess iron that results in damage to the liver, endocrine organs, and heart. Four orally active agents have reached clinical trials in the last decade. The agent under consideration in this paper, deferiprone (1,2-dimethyl-3-hydroxypyridin-4-one), has shown some promise, but, according to the studies discussed here, may not provide adequate sustained control of body iron in a substantial proportion of Cooley's anemia patients.

While the parenteral iron-chelating agent desferrioxamine B has anti-malarial activity in humans, the usefulness of an orally active chelator for this indication has not been investigated previously in vivo. We conducted a prospective, double-blind, placebo-controlled, cross-over trial of deferiprone (L1; CP20; 1,2-dimethyl-3-hydroxypyridin-4-one) in 25 adult Zambians with asymptomatic Plasmodium falciparum parasitemia. Deferiprone was administered daily for three or four days in divided doses of 75 or 100 mg/kg of body weight, dosages that are effective for treating iron overload. No reduction in asexual intra-erythrocytic parasites was observed during or after deferiprone treatment. The mean peak plasma concentration of deferiprone (108.9 +/- 24.9 micromol/L) achieved was within the range demonstrated to inhibit the growth of P. falciparum in vitro, but the systemic exposure as determined by the 24-hr plasma concentration-time curve would not be predicted inhibit growth in vivo. No evidence of deferiprone-associated hematological toxicity was noted in this short-term study of these subjects, all of whom had clinical evidence of normal body iron stores. Because of the risk of neutropenia and other adverse effects with higher doses or prolonged use of the chelator, additional trials of deferiprone as a sole anti-malarial agent would not seem to be justified. In contrast, further efforts are needed to develop other orally active iron-chelating agents specifically for their anti-malarial action.

Short-term deferiprone may reduce body iron in some patients with thalassaemia major. Concerns regarding potential immunosuppressive effects of deferiprone have been raised from results of animal studies and case reports in humans. We studied immune function in 57 thalassaemia patients: 36 treated with deferiprone (L1; CP020) and 21 treated with desferrioxamine (DFO). Circulating B lymphocytes were increased in all patient groups. No differences were detected between treatment groups in percentages of circulating lymphocytes, concentrations of IgG, IgM or IgA, specific antibody titres, complement levels, or in vitro lymphocyte proliferation. No clinically important infections were observed in any patient. These data suggest that no clinical or laboratory changes consistent with immuno-suppression or immunodeficiency are observed during deferiprone therapy.

Recently, we demonstrated that administration of the orally active iron chelating agent deferiprone (1,2-dimethyl-3-hydroxypyrid-4-one (L1)) at 6-hour intervals results in significantly greater urinary iron excretion than that induced during administration of the drug at 12-hour intervals. That study was conducted in thalassemia patients, all of whom had received a packed red cell transfusion of 15 cc/kg. 72 hours prior to evaluation of urinary iron excretion, at a time when endogenous erythropoiesis would be expected to be at its lowest. In clinical practice however, thalassemia patients, suppression of endogenous erythropoiesis is not sustained between transfusions. We set out to determine the influence that administration of deferiprone has on urinary iron excretion at lower hemoglobin concentrations, immediately prior to transfusion. We hypothesized that hemoglobin levels will affect the ability of deferiprone to chelate iron. Ten regularly transfused patients with homozygous beta-thalassemia (HBT) aged mean +/- SD, 20.9 +/- 4.7, range 13 - 27 years, receiving long-term therapy with deferiprone, were treated with deferiprone 75 mg/kg/day, administered every 6 hours (or every 12 hours) for 72 hours immediately prior to a blood transfusion in the first month. One month later each patient received the other of the 2 dosing regimens for 72 hours immediately prior to transfusion. The deferiprone-induced 24-hour urinary iron excretion was similar during both dosing regimens; 0.56 +/- 0.45 mg/kg when L1 was given every 6 hours and 0.48 +/- 0.52 mg/kg when L1 was administered every 12 hours (p = 0.79). However, the calculated 24-hour area under the plasma concentration-time curve (AUC0-24) of deferiprone was significantly lower when deferiprone was administered at 6-hour intervals (6,762.8 +/- 1,601.6 mg*min/l), than that observed when deferiprone was administered every 12 hours (8,250.1 +/- 1,235.7 mg*min/l) (p = 0.04). The pharmacokinetics of deferiprone when administered immediately prior to transfusions are different from those following transfusions. More studies assessing total body iron excretion are needed to determine the contribution of the fecal route in iron excretion.

Data from several trials have provided evidence for the efficacy of deferiprone in the treatment of iron overload in thalassemia major. Deferiprone has now been shown to induce sustained decreases in tissue iron to concentrations that are associated with survival free of the complications of iron overload in deferoxamine-treated patients. Despite this evidence of efficacy, the risk of agranulocytosis mandates a careful evaluation of the risk of this drug in patients willing and able to use deferoxamine. The incidence of agranulocytosis associated with deferiprone is under study in a prospective multicenter trial in Canada, Italy, and the United States, under corporate sponsorship by Apotex Research in Canada. The results of this study should determine the risk associated with the use of this agent and may provide the data required for a US Food and Drug Administration decision regarding licensing of this agent for the treatment of iron overload, a goal supported by investigators worldwide.

Data from several trials have provided direct and supportive evidence for the efficacy of deferiprone in the treatment of iron overload in thalassemia major. Deferiprone has been shown to induce sustained decreases in body iron to concentrations associated with survival free from the complications of iron overload in deferoxamine (DFO)-treated patients. Despite this evidence of efficacy, the risk of agranulocytosis mandates a careful evaluation in patients willing and able to use DFO. The incidence of agranulocytosis associated with deferiprone is under study in a prospective multicenter trial in Canada, Italy and the United States, under corporate sponsorship (Apotex Research, Canada). The results of this study should determine the risk associated with the use of this agent, and may provide the data required for an FDA decision regarding licensing of this agent for the treatment of iron overload, a goal supported by investigators worldwide.

This report updates the combined experience of four centres involved in the long-term treatment of transfusional iron overload in 84 patients with the oral iron chelator deferiprone (L1) over 167 patient-years. The source of L1 was variable, including two university research laboratories and three pharmaceutical firms. Compliance was rated as excellent in 48%, intermediate in 36%, and poor in 16% of patients. On a mean L1 dose of 73-81 mg/kg/d, urinary iron excretion was stable, at around 0.5 mg/kg/d, with no indication of a diminishing response with time. Serum ferritin showed a very steady decrease with time from an initial mean +/- 1 SD of 4207 +/- 3118 to 1779 +/- 1154 micrograms/l after 48 months (P < 0.001). 17 patients abandoned L1 therapy. Major complications of L1 requiring permanent discontinuation of treatment included agranulocytosis (three), severe nausea (four), arthritis (two) and persistent liver dysfunction (one). The remaining patients abandoned treatment because of low compliance (three) and conditions unrelated to L1 toxicity (four). Lesser complications permitting continued L1 treatment included transient mild neutropenia (four), zinc deficiency (12), transient increase in liver enzymes (37), moderate nausea (three) and arthropathy (17). There was no treatment-related mortality. Although the complications associated with L1 treatment are significant and require close monitoring, they do not preclude effective long-term therapy in the vast majority of patients. Further well-controlled prospective studies of L1 are required in order to enable proper judgement of its suitability for general long-term clinical use.

Hepatic non-transferrin-bound Fe (NTBI) flux and its regulation were characterized by measuring the uptake of Fe from [59Fe]/nitrilotriacetate (NTA) complexes in control and Fe-loaded cultures of human hepatocellular carcinoma cells (HepG2). Exposure to ferric ammonium citrate (FAC) for 1 to 7 days resulted in a time- and dose-dependent increase in the rate of NTBI uptake. In contrast to previous studies showing a dependence of the rate of Fe uptake on extracellular Fe, this was positively correlated with total cellular Fe content. The Fe3+ chelating agents deferoxamine (DFO), 1,2-dimethyl-3-hydroxypyrid-4-one (CP 020) and 1,2-diethyl-3-hydroxypyrid-4-one (CP 094) prevented or diminished the increase in NTBI transport when present during Fe loading and reversed the stimulation in pre-loaded cells in relation to their abilities to decrease intracellular iron. Although saturation of the Fe uptake process was not achieved in control cells, kinetic modelling to include linear diffusion-controlled processes yielded estimated parameters of Km = 4.3 microM and Vmax = 2.6 fmol/micrograms protein/min for the underlying process. There was a significant increase in the apparent Vmax (31.2 fmol/micrograms protein per min) for NTBI uptake in Fe-loaded cells, suggesting that Fe loading increases the number of a rate-limiting carrier site for Fe. Km also increased to 15.2 microM, comparable to values reported when whole liver is perfused with FeSO4. We conclude that HepG2 cells possess a transferrin-independent mechanism of Fe accumulation that responds reversibly to a regulatory intracellular Fe pool.

Background: To determine whether the orally active iron chelator deferiprone (1,2-dimethyl-3-hydroxy-pyridin-4-one) is efficacious in the treatment of iron overload in patients with thalassemia major, we conducted a prospective trial of deferiprone in 21 patients unable or unwilling to use standard chelation therapy with parenteral deferoxamine., Methods: Hepatic iron stores were determined yearly by chemical analysis of liver-biopsy specimens or magnetic-susceptibility measurements. Detailed clinical and laboratory studies were used to monitor safety and compliance., Results: The patients received deferiprone therapy for a mean (+/-SE) of 3.1 +/- 0.3 years. Ten patients in whom previous chelation therapy with deferoxamine had been ineffective had initial hepatic iron concentrations of at least 80 mumol per gram of liver, wet weight -- values associated with complications of iron overload. Hepatic iron concentrations decreased in all 10 patients, from 125.3 +/- 11.5 to 60.3 +/- 9.6 mumol per gram (P < 0.005), with values that were less than 80 mumol per gram in 8 of the 10 patients (P < 0.005). In all 11 patients in whom deferoxamine therapy had previously been effective, deferiprone maintained hepatic iron concentrations below 80 mumol of iron per gram., Conclusions: Oral deferiprone induces sustained decreases in body iron to concentrations compatible with the avoidance of complications from iron overload. The risk of agranulocytosis associated with deferiprone may restrict its administration to patients who are unable or unwilling to use deferoxamine.

The assessment of compliance is critical in the evaluation of the effectiveness of a new therapeutic agent. Fifteen patients with transfusion-dependent beta-thalassemia, many of whom had previously demonstrated erratic compliance with deferoxamine, were enrolled in a clinical trial of a new oral iron chelator, 1,2-dimethyl-3-hydroxypyrid-4-one (L1). Their compliance with this medication was estimated by several existing methods and the novel Medication Event Monitoring System (MEMS). Overall compliance as assessed by the MEMS was 78.5 +/- 13.0% of prescribed doses taken, significantly lower than the corresponding rates calculated by pill counts and diaries (91.5 +/- 9.2% and 94.1 +/- 4.3%, respectively). However, several serious problems were encountered with the MEMS, mostly in the form of incorrect use of the device by the patients. Disclosure of the nature of the MEMS and the compliance monitoring process did not alter the rate of adherence with L1 therapy. Compliance as determined by pill counts did not differ between the 1st and 2nd 6-month periods. Although not reaching statistical significance, a trend towards better L1 compliance occurred in those patients in whom serum ferritin levels decreased. Patients who filled at least 50% of their diaries had significantly better compliance by pill counts than those who completed less than 50% of their diaries (95.9 +/- 4.1% and 86.5 +/- 11.1%, respectively). Steady-state L1 trough concentrations and 24-hour urinary iron excretion did not correlate with L1 compliance.(ABSTRACT TRUNCATED AT 250 WORDS)

The iron chelator deferiprone (L1) reduces tissue iron stores in iron-loaded patients. Three of sixteen patients treated with deferiprone developed joint pain and swelling without evidence of systemic lupus erythematosus (SLE). Articular cartilage, synovial hypertrophy and iron deposition, and synovial lining cell proliferation, with no inflammatory or allergic reaction, were observed on synovial exploration and biopsy. Symptoms resolved partly or completely during continued drug administration. We hypothesise that deferiprone-induced shifts of iron to synovium resulted in tissue damage, accelerated by free-radical formation during incomplete complexation of iron and this bidentate chelator. This deferiprone-associated symptom complex is not associated with drug-induced SLE, and does not progress in severity during continued therapy.

Several life-threatening complications of the common disorder sickle cell disease require management with red blood cell transfusions and, hence, long-term iron-chelating therapy. The efficacy of the oral iron chelator 1,2-dimethyl-3-hydroxypyrid-4-one (L1) has not previously been determined in patients with sickle cell disease. We compared the efficacy of L1 to that of standard-dose subcutaneous deferoxamine in four regularly transfused patients with homozygous sickle cell disease, who had evidence of severe iron overload and a history of poor compliance with deferoxamine. Determination of 24-hour urinary iron excretion conducted over 5 days immediately after transfusion showed that the mean daily urinary iron excretion induced by L1 at 75 mg/kg/d (0.48 +/- 0.23 mg/kg) was equivalent to that induced by deferoxamine at 50 mg/kg/d (0.39 +/- 0.06 mg/kg). In two of three patients studied, a significant (P < .025) increase in mean daily urinary iron excretion was achieved when the dose of L1 was increased to 100 mg/kg/d. Total iron balance studies, which quantitated both urinary and stool iron excretion on L1 and deferoxamine, determined that mean total daily iron excretion induced by deferoxamine (0.88 +/- 0.05 mg/kg) was significantly greater (P < .05) than that induced by L1 (0.53 +/- 0.17 mg/kg), attributable to the significantly greater stool iron excretion during deferoxamine treatment (0.50 +/- 0.16 mg/kg/d) compared with that measured during L1 treatment (0.12 +/- 0.08 mg/kg/d, P < .01). Stool iron excretion accounted for a significantly greater percentage of total iron excretion during deferoxamine treatment (59% +/- 20%) than during L1 treatment (23% +/- 14%, P < .01). These iron balance studies are the first to compare total iron excretion induced by L1 with that achieved by deferoxamine. They demonstrate that the mean total daily iron excretion during L1 treatment (0.53 +/- 0.17 mg/kg) is sufficient to maintain net negative iron balance in most regularly transfused patients with sickle cell disease. Because long-term compliance with L1 has been shown previously to be superior to that with deferoxamine in patients with homozygous beta-thalassemia, the use of L1 should increase the long-term effectiveness of iron chelation in patients with sickle cell disease.

Objective: To examine the effect of frequency of oral administration of 1,2-dimethyl-3-hydroxypyrid-4-one (L1) on urinary iron excretion., Hypothesis: Sustained serum concentrations of L1 will cause more iron chelation than the same daily dose given in larger but less frequent amounts., Patients and Methods: Ten patients with thalassemia with a mean age of 20.9 +/- 4.7 years (range, 13 to 27 years), who were receiving regular treatment with 75 to 100 mg/kg/day oral L1, received 75 mg/kg/day L1 orally in equally divided doses: every 6 hours for 3 days and every 12 hours for 3 days. The two study periods occurred 1 month apart immediately after the monthly blood transfusions. Urine was collected for two consecutive 24-hour periods during each of the different schedules. Serial blood samples were collected from six patients over a 6-hour period and analyzed for total L1 and the L1 glucuronide metabolite concentrations., Results: The patient's mean hemoglobin levels (138.8 +/- 12.5 and 139.0 +/- 11.6 gm/L) and ferritin levels (2856.4 +/- 2207.8 and 2890.0 +/- 2264.4 micrograms/L) were similar during the every-6-hour and every-12-hour L1 administrations, respectively. There was significantly more urinary iron excretion when L1 was administered every 6 hours (0.59 +/- 0.29 mg/kg/day) versus every 12 hours (0.40 +/- 0.26 mg/kg/day; p = 0.0129). Calculated 24-hour area under the plasma concentration-time curve of L1 was similar during the every-6-hour (7023.9 +/- 2637.8 mg.min/L) and every-12-hour (7050.1 +/- 1668.8 mg.min/L) experiments., Conclusions: These data suggest that the sustained presence of L1 in the blood results in greater chelation of iron than that observed with larger, less frequent doses.

Given the mortality and morbidity associated with acute iron intoxication, effective iron chelation which is easily administered in an emergency situation would be ideal. The pharmacokinetics of L1 were examined in 5 healthy adult male volunteers to assess its potential for use in acute iron overload. Ferrous sulfate (600 mg), L1 (900 mg), and ferrous sulfate and L1 were administered on three separate days, each one week apart. On each test day, blood samples were collected at regular intervals for the measurement of plasma L1 and total iron. Pharmacokinetic values were calculated. The data were also compared to that obtained in 10 patients with beta-thalassemia and chronic iron overload. In the normal volunteers, a 20% decrease in the area under the concentration time curve of plasma iron and of plasma L1 was demonstrated when they were co-administered. There was no change in urinary iron excretion when L1 was given with iron (p = 0.414). The elimination half-life of L1 in the thalassemia patients (137.65 +/- 48.65 min) was significantly longer than that in the healthy volunteers (77.56 +/- 13.0) (p = 0.0047) due to larger apparent volume of distribution. In all of the iron-overloaded individuals L1 resulted in increased urinary iron excretion. None of the other pharmacokinetic variables compared were significantly different between these two groups. These studies indicate that at levels below saturation, transferrin does not allow L1 to remove absorbed iron in healthy volunteers, whereas in thalassemia patients, who are beyond saturation of their iron binding capacity, the drug binds iron and promotes its excretion.

Accumulation of Fe in the myocardium in circumstances of transferrin saturation is associated with heart failure in Fe-loaded patients. To characterize the underlying causes of this phenomenon, we measured the flux as well as the speciation of Fe in normal and Fe-loaded cultures of rat myocardiocytes. Fe loading with low-molecular-weight Fe (ferric ammonium citrate) promoted a dose- and time-dependent increase in the rate of uptake of non-transferrin-bound Fe (NTBI) that was positively correlated (R = 0.9, p < 0.005) with cellular iron content. At concentrations sufficient to produce this up-regulation, membrane integrity was unaffected but the rate of spontaneous beating of the cells was decreased by 60%. The enhanced rate of NTBI uptake in Fe-loaded cells reverted to control rates after treatment with therapeutic concentrations of Fe chelators deferoxamine, 1,2-dimethyl-3-hydroxypyrid-4-one and 1,2-diethyl-3-hydroxypyrid-4-one under conditions where approximately 80% of the cellular Fe was removed by chelation. Fe loading of cultured myocytes also induced shifts in Fe speciation. Thus the ratio of Fe bound in hemosiderin-like precipitates to ferritin-bound Fe increased twofold, from a range of 0.84 to 1.44 in control cells to 1.96 to 3.3 in iron-loaded cells. This increased ratio was similar to that measured in the heart and liver of a thalassemic patient who underwent a double transplant for the failure of both organs, even though the Fe content of the heart (mean, 5.8 mg Fe/gm dry weight) was much less than that of the liver (28.1 mg/gm dry weight). These results suggest that increased rates of uptake of NTBI may exacerbate iron loading of the heart and contribute to iron-mediated cardiotoxicity, whereas the clinical benefits of chelation therapy may be enhanced by the down-regulation of NTBI uptake.

Despite the successes of deferoxamine (DFO) in the treatment and prevention of iron overload, an effective orally available iron chelating drug is needed, since erratic compliance with irritating, cumbersome parenteral infusions still results in fatal iron accumulation in many patients. Disorders of increased iron absorption should also benefit from the development of safe and effective iron chelating agents. Individuals with non-transfusion-dependent thalassemia (thalassemia "intermedia"), exhibit excessive dietary iron absorption that can lead to serious iron loading by the second or third decade of life. An orally effective iron-chelating drug would have major therapeutic advantages for all these patients.

In patients with thalassemia intermedia in whom hyperabsorption of iron may result in serious organ dysfunction, an orally effective iron-chelating drug would have major therapeutic advantages, especially for the many patients with thalassemia intermedia in the Third World. We report reduction in tissue iron stores and normalization of serum ferritin concentration after 9-month therapy with the oral chelator 1,2-dimethyl-3-hydroxypyrid-4-one (L1) in a 29-year-old man with thalassemia intermedia and clinically significant iron overload (SF 2,174 micrograms/L, transferrin saturation 100%; elevated AST and ALT, abnormal cardiac radionuclide angiogram) who was enrolled in the study with L1 75 mg/kg/day after he refused deferoxamine therapy. L1-Induced 24-hour urinary iron excretion during the first 6 months of therapy was (mean +/- SD, range) 53 +/- 30 (11 to 109) mg (0.77 mg/kg), declining during the last 3 months of L1 to 24 +/- 14 (13-40) mg (0.36 mg/kg), as serum ferritin decreased steadily to normal range (present value, 251 micrograms/L). Dramatic improvement in signal intensity of the liver and mild improvement in that of the heart was shown by comparison of T1-weighted spin echo magnetic resonance imaging with images obtained immediately before L1 administration was observed after 9 months of L1 therapy. Hepatic iron concentration decreased from 14.6 mg/g dry weight of liver before L1 therapy to 1.9 mg/g liver after 9 months of therapy. This constitutes the first report of normalization of serum ferritin concentration in parallel with demonstrated reduction in tissue iron stores as a result of treatment with L1. Use of L1 as a therapeutic option in patients with thalassemia intermedia and iron overload appears warranted.

The accurate assessment of patient compliance is especially crucial in evaluating the efficacy of a new treatment. Because of the problems associated with parenteral desferrioxamine, the development of a safe, effective, and convenient iron chelator is of high priority. The high morbidity and mortality associated with iron overload requires careful evaluation of the ability of any new agent to promote long term effective iron chelation. Patients' compliance with an orally available chelating agent, 1,2,-dimethyl-3-hydroxypyrid-4-one (L1), that has been demonstrated to induce in vivo iron excretion equivalent to that of desferrioxamine during supervised short term administration, was examined. Compliance was assessed in seven patients by patient interview, by daily diaries reviewed monthly with each patient, and with the use of the Medication Event Monitoring System (MEMS) standard pill bottles with microprocessors in the cap that record the timing and frequency of bottle openings. L1 was dispensed in MEMS containers to the patients, who, unaware of their significance, recorded compliance using a daily diary. Overall compliance rate (% of prescribed doses taken) measured by MEMS was 88.7 +/- 6.8%. When 'doubling of doses' was accounted for, significantly poorer compliance with L1 was noted by MEMS (91.7 +/- 7.4%) than by patients' diaries (95.7 +/- 5.2%). There was no significant difference in patient compliance recorded between the first and last 30 day period of drug administration. MEMS can eliminate the confounding variable of erratic patient compliance in the evaluation of a new drug's efficacy. As MEMS cannot distinguish a missed dose from one doubled at the next bottle opening, the use of patient diaries is a useful adjunct to the accurate assessment of compliance and should be combined with the use of MEMS.

Single-dose and steady-state pharmacokinetics of the new oral iron chelator, 1,2-dimethyl-3-hydroxypyrid-4-one (L1) were studied in 14 patients with thalassemia and correlated with iron excretion. Food prolongs the rate of absorption of L1, but it does not affect significantly the extent of absorption measured by the area under the plasma concentration-time curve. Similarly, it does not affect the chelation potential of the drug. The mean elimination half-life of the drug is 3 hours, suggesting that a divided dose every 8 hours may assure better chelation. Our steady-state studies reveal that urinary iron excretion is independently influenced by body iron load (measured by ferritin levels) and by steady-state trough concentrations of the drug. While patients were receiving an unchanged regimen of 75 mg/kg/day, we have detected a gradual and significant decrease in trough concentrations in the presence of unchanged patients' compliance monitored by the Medication Event Monitoring System, diaries, and pill count. These findings suggest self-induction of L1 metabolism or decreased absorption during long-term therapy. Because of the concentration-dependent iron excretion, patients may need increasing doses to achieve negative iron balance.

1,2-Dimethyl-3-hydroxypyridin-4-one (CP020 or L1) is a novel oral iron chelator that has proved to be effective in animals and humans. A rapid, accurate, and sensitive high-performance liquid chromatography method is described for measuring L1 in human plasma using a Hypercarb 7 microns column and monitoring the column eluent by ultraviolet absorption at 280 nm. CP020 and the internal standard (CP094) were extracted into dichloromethane (2 x 5 ml) from plasma at neutral pH [0.25 ml of plasma + 0.75 ml of 60 mM 3-(N-morpholino)propanesulfonic acid buffer, pH 7.4]. The method proved to be linear (r2 = 0.998) in the clinical range of 0.5-50 micrograms/ml when 0.25 ml of plasma was used, with the coefficient of variation less than 10% even at the lower concentration range.

Background: Patients with transfusion-dependent thalassemia major tend to have abnormal growth and sexual maturation at puberty, presumably as a result of pituitary iron overload. This study was designed to determine whether chelation therapy with deferoxamine before the age of puberty would ameliorate this problem., Methods: We examined 40 patients over 14 years of age with transfusion-dependent thalassemia major. The 19 patients in group A (mean [+/- SD] age at study, 17.0 +/- 1.5 years) had begun nightly treatment with subcutaneous deferoxamine before the age of 10 (mean age at start of treatment, 7.5 +/- 1.8 years). The 21 patients in group B (mean age, 24.1 +/- 3.8 years) had begun treatment after the age of 10 (mean age at start of treatment, 14.4 +/- 4.7 years)., Results: The abnormal findings were essentially confined to sexual development. The final height did not differ between groups or from the mean parental height in each group. Ninety percent of the patients in group A had normal sexual development, as compared with 38 percent of those in group B (P = 0.001). Outcomes were correlated with indexes of iron overload; the patients in group A had lower serum ferritin levels before chelation treatment (P = 0.01) and lower average serum ferritin levels during treatment (P = 0.005)., Conclusions: Beginning chelation treatment with deferoxamine before the age of puberty can help children with transfusion-dependent thalassemia major to attain normal sexual maturation.