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Five-year trial of deferiprone chelation therapy in thalassaemia major patients.

Twelve thalassaemia major patients have been given deferiprone 75 mg/kg body weight daily as iron chelation therapy for 5 years. Their ages ranged from 18 to 34 years (mean 24.2) at the end of the study. Two patients were hepatitis C virus (HCV) mRNA positive and a further 5 were positive for HCV antibody. The mean serum ferritin level fell significantly from 4,302 +/- 2,245 microg/l SD at baseline to 3,032 +/- 1,155 microg/l at 2 years (p = 0.037) and 2,229 +/- 1,070 microg/l (p = 0.007) at 5 years. At the end of the study, liver iron ranged from 3.59 to 23.7 mg/g dry weight (mean 11.9 +/- 5.4), 3 patients having levels >15 mg/g. There was no significant change in serum AST levels, but ALT levels fell significantly at 2 years (p = 0.019) and 5 years (p = 0.001). Liver biopsy at the end of the study showed no evidence of hepatic fibrosis caused by deferiprone. Cardiac studies showed no overall change in left ventricular ejection fraction but a significant improvement in isovolumic relaxation time (p = 0.045). We conclude that in this albeit small group of thalassaemia major patients, deferiprone was a safe long-term method of iron chelation. In a minority, higher doses of deferiprone or a combination with desferrioxamine would be needed to lower liver iron below 15 mg/g.

Adolescent↗

Safety and effectiveness of 100 mg/kg/day deferiprone in patients with thalassemia major: a two-year study.

Deferiprone at a dose of 75 mg/kg/day is not sufficiently effective to maintain iron stores at a level which has been considered safe in all patients with iron overload. Our main aim was to determine the safety of long-term therapy with high-dose (100 mg/kg/day) deferiprone. A secondary aim was to determine the efficacy of this high dose. Twelve thalassemia major patients received deferiprone at a dose of 100 mg/kg/day over 2 years. Transient aspartate aminotransferase increase (8 patients), gastrointestinal discomfort (3 patients) and arthralgia (2 patients) were the most commonly reported side effects. None of the patients discontinued therapy. The mean serum ferritin level fell from 3,901 +/- 3,618 to 1,790 +/- 2,205 microg/l after 2 years (p < 0.05). Five of the 12 patients continued to receive deferiprone for an additional 3 years. No new side effects were encountered. The mean serum ferritin level in this subgroup was initially 2,510 +/- 332 microg/l and dropped to 1,511 +/- 664 microg/l after 5 years (p < 0.05). Liver iron levels at the end of the 2-year study ranged from 1.0 to 30.9 mg/g dry weight, 3 of the patients having levels above 15 mg/g.

Adolescent↗

Advances in iron overload therapies. prospects for effective use of deferiprone (L1), deferoxamine, the new experimental chelators ICL670, GT56-252, L1NA11 and their combinations.

Effective new therapies and mechanisms have been developed for the targeting and prevention of iron overload and toxicity in thalassaemia and idiopathic haemochromatosis patients. A new era in the development of chelating drugs began with the introduction of deferiprone or L1, which as a monotherapy or in combination with deferoxamine can be used universally for effective chelation treatments, rapid iron removal, maintenance of low iron stores and prevention of heart and other organ damage caused by iron overload. Several experimental iron chelators such as deferasirox (4-[3,5-bis (2-hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid) or ICL670, deferitrin (4,5-dihydro-2- (2,4-dihydroxyphenyl)-4-methylthiazole-4 (S)-carboxylic acid) or GT56-252, 1-allyl-2-methyl-3-hydroxypyrid-4-one or L1NAll and starch deferoxamine polymers have reached different stages of clinical development. The lipophilic ICL670, which can only be administered once daily is generally ineffective in causing negative iron balance but is effective in reducing liver iron. It is suspected that it may increase iron absorption and the redistribution of iron from the liver to the heart and other organs. The experimental iron chelators do not appear to have significant advantages in efficacy and toxicity by comparison to deferiprone, deferoxamine or their combination. However, the prospect of combination therapies using deferiprone, deferoxamine and new chelators will provide new mechanisms of chelator interactions, which may lead to higher efficacy and lower toxicity by comparison to monotherapies. A major disadvantage of the experimental chelators is that even if they are approved for clinical use, they are unlikely to be as inexpensive as deferiprone and become available to the vast majority of thalassaemia patients, who live in developing countries.

Benzoates↗

Acute iron intoxication: the efficacy of deferiprone and sodium biocarbonate in the prevention of iron absorption from the digestive tract.

To determine whether enteral deferiprone given after a loading dose of liquid iron interferes with iron absorption from the digestive tract, prospective randomized animal study was initiated using Sprague-Dawley rats. The rats were given 20 mg elemental iron/kg as a ferrous sulfate solution + 1 mEq sodium bicarbonate/kg, and then dosed orally with 150 mg deferiprone/kg immediately or after 15 min. Serum iron levels were measured at 1, 3, 5 and 24 h; feces were collected for 24 h. The 20 mg elemental iron/kg caused a significant and rapid increase in serum iron levels to > 350 micrograms/dL within 20 min of oral dosing. Deferiprone, if given immediately after the iron, produced a significant decrease in serum iron levels and a 2-fold increase in iron excretion in feces. Effectiveness was delayed when the deferiprone was given 15 min after the iron dosing. Enteral deferiprone might be useful in preventing cases of acute iron intoxication.

Animals↗

Deferiprone (L1) as an adjuvant therapy for Plasmodium falciparum malaria.

BACKGROUND & OBJECTIVES: Mortality due to Plasmodium falciparum infection remains high in India, hence any modality of treatment which can improve the outcome of this disease is worth exploring. The present study was undertaken to see whether addition of an oral iron chelator, deferiprone (L1) to the conventional treatment regime for P. falciparum infection improves the clinical course and final outcome. METHODS: In this prospective, randomised double blind trial, 45 consecutive patients with P. falciparum infection were randomised into two groups. Patients in Group I (control group, 21 patients) received standard quinine and doxycycline therapy along with supportive therapy and placebo capsules for 10 days. Patients in Group II (24 patients) received the same treatment as Group I but in place of placebo capsule received deferiprone capsules 75 mg/kg/day in 12 hourly divided doses. The parameters evaluated included the time taken in resolution of parasitaemia, fever and coma, differences in final outcome i.e., death or other severe complications, and side effects and deferiprone tolerance. RESULTS: Four patients in Group I and two in Group II died (P > 0.05). The resolution of fever and coma was significantly faster in Group II (P < 0.05) and parasitaemia cleared 24 h earlier in this Group. The drug was well tolerated and had no side effects. INTERPRETATION & CONCLUSION: Deferiprone (L1) seems to be a promising agent as an adjuvant in the treatment for severe P. falciparum malaria infection.

Adolescent↗

Combined therapy with deferiprone and desferrioxamine in thalassemia major.

BACKGROUND AND OBJECTIVES: Effective and convenient iron chelation remains one of the main targets of clinical management of thalassemia major. The combined treatment with desferrioxamine and deferiprone could have an increased chelation efficacy and sometimes allow drug doses and toxicity to be reduced and the number of days of desferrioxamine infusion to be decreased, improving compliance and quality of life. DESIGN AND METHODS: We used combined therapy with desferrioxamine and deferiprone to treat 79 patients with severe iron overload (serum ferritin higher than 3000 ng/mL) who had low compliance with subcutaneous desferrioxamine. RESULTS: Total therapy exposure was 201 patient-years. Three patients developed agranulocytosis and seven mild neutropenia. Other adverse effects were nausea, vomiting, abdominal pain, increased concentrations of liver transaminases and joint pain. The efficacy of combined therapy was evaluated in 64 patients treated for at least 12 months. Ferritin decreased from 5243+/-2345 to 3439+/-2446 ng/mL, p<0.001). Mean urinary iron excretion during combined therapy was double that with desferrioxamine or deferiprone monotherapy. In 20 patients receiving heart therapy at baseline, left ventricular ejection fraction increased from 48.6+/-9% to 57+/-6% (p=0.0001) over 12 to 57 months, without modifying the cardiac treatment. INTERPRETATION AND CONCLUSIONS: Continuous deferiprone treatment with intermittent administration of subcutaneous desferrioxamine is a practical and effective procedure to decrease severe iron overload in patients with thalassemia major. This study also shows that the combined therapy is associated with an improvement in heart function.

Adolescent↗

Effective new treatments of iron overload in thalassaemia using the ICOC combination therapy protocol of deferiprone (L1) and deferoxamine and of new chelating drugs.

An expert group of the International Committee on Oral Chelators (ICOC) has recommended a universally effective chelation combination protocol of oral deferiprone (L1) during the day (80-110 mg/kg /day) and subcutaneous deferoxamine (40-60 mg/kg) of a minimum of three nights per week for the rapid, safe and effective depletion of excess body iron in transfused iron loaded patients. Following the clearance of excess cardiac and liver iron load, deferiprone (L1) monotherapy at doses exceeding 80 mg/kg/day has been recommended for preventing the re-accumulation of excess iron in the heart and other organs. New chelators such as deferasirox may also be used in combinations with deferiprone (L1) and deferoxamine, especially in patients not tolerating the deferiprone (L1) / deferoxamine combination.

Deferiprone↗

Estimates of the effect on hepatic iron of oral deferiprone compared with subcutaneous desferrioxamine for treatment of iron overload in thalassemia major: a systematic review.

BACKGROUND: Beta thalassemia major requires regular blood transfusions and iron chelation to alleviate the harmful accumulation of iron. Evidence on the efficacy and safety of the available agents, desferrioxamine and deferiprone, is derived from small, non-comparative, heterogeneous observational studies. This evidence was reviewed to quantitatively compare the ability of these chelators to reduce hepatic iron. METHODS: The literature was searched using Medline and all reports addressing the effect of either chelator on hepatic iron were considered. Data were abstracted independently by two investigators. Analyses were performed using reported individual patient data. Hepatic iron concentrations at study end and changes over time were compared using ANCOVA, controlling for initial iron load. Differences in the proportions of patients improving were tested using chi2. RESULTS: Eight of 11 reports identified provided patient-level data relating to 30 desferrioxamine- and 68 deferiprone-treated patients. Desferrioxamine was more likely than optimal dose deferiprone to decrease hepatic iron over the average follow-up of 45 months (odds ratio, 19.0, 95% CI, 2.4 to 151.4). The degree of improvement was also larger with desferrioxamine. CONCLUSIONS: This analysis suggests that desferrioxamine is more effective than deferiprone in lowering hepatic iron. This comparative analysis - despite its limitations - should prove beneficial to physicians faced with the challenge of selecting the optimal treatment for their patients.

Journal Article↗

Comparative efficacy and toxicity of desferrioxamine, deferiprone and other iron and aluminium chelating drugs.

The efficacy and toxicity aspects of the iron and aluminium chelating drugs desferrioxamine and deferiprone (L1, 1,2-dimethyl-3-hydroxypyrid-4-one), have been compared. Major emphasis was given in the use of these two and also of other chelators in conditions of iron overload, imbalance and toxicity, as well as the incidence and possible causes of toxic side effects in both animals and humans. The chemical basis of chelation and the interaction of these chelators with the iron pools are discussed within the context of clinical application in iron overload and other conditions such as renal dialysis, rheumatoid arthritis, cancer, heart disease, malaria, etc. The design and development of new orally active alpha-ketohydroxypyridine and other chelators are considered and compared with 14 other chelators which have been previously tested in man for the removal of iron, most of which, however, were later abandoned because of low efficacy or major toxicity. The design of new therapeutic protocols based on the pharmacological, toxicological and metabolic transformation properties of the chelating drugs is also being considered, within the context of maximising their efficacy and minimising their toxicity. Overall, oral deferiprone appears to be as effective as s.c. desferrioxamine in the removal of iron and aluminium in man and to have a similar but different toxicity profile from desferrioxamine in both animals and man. The low cost and oral activity of deferiprone will make it the drug of choice for the vast majority of patients, who are not currently being chelated either because they cannot afford the high cost of desferrioxamine therapy or are not complying or have toxic side effects with its s.c. administration.

Administration, Oral↗

Liver iron and fibrosis during long-term treatment with deferiprone in Swiss thalassaemic patients.

Serum ferritin levels, hepatic histology and iron concentration were studied in a 'veteran' group of seven Swiss beta-thalassaemic patients after 93-99 months of treatment with the oral iron chelator deferiprone (L1), and another four patients who had received 54-82 months of L1 therapy. Despite continuous compliance, unexplained resurgence of serum ferritin levels occurred in 4/7 patients of the 'veteran' group after 4-5 years on L1. In three of these a concomitant increase of liver iron was also observed. Hepatic histology revealed significantly higher degrees of fibrosis in 6/11 hepatitis C (HC)-positive patients (fibrosis scores 1-5, mean 3.0) than in the HC-negative group (fibrosis score 0-2, mean 0.8). Two HC-negative patients had no detectable fibrosis after 98 and 93 months on deferiprone. Therefore the hepatic pathology in these patients cannot definitely be attributed as a side-effect of deferiprone. Chronic active hepatitis C and the accumulation of iron are the major causative factors to be considered.

Adolescent↗

Monitoring long-term efficacy of iron chelation therapy by deferiprone and desferrioxamine in patients with beta-thalassaemia major: application of SQUID biomagnetic liver susceptometry.

In this non-randomized prospective study, liver and spleen iron concentrations were monitored annually over a 4-year period by non-invasive Superconducting Quantum Interference Device biomagnetometry in 54 beta-thalassaemia major patients (age, 7-22 years) receiving treatment with deferiprone (75 mg/kg/d). Median liver iron concentrations increased significantly from 1456 to 2029 and 2449 microg/g(liver) at baseline, after 2.0 and 3.2 years respectively. Another group of 51 thalassaemic patients (aged 4-34 years) who received desferrioxamine s.c. for 1.9 years increased their liver iron concentration from 1076 to 1260 microg/g(liver). Taking into account the increase of the daily iron input from transfusions of 3.6 mg/d, caused by weight gain in 67% of the patients treated with deferiprone, a larger total body iron elimination rate was achieved after 2 years than at baseline. A negative ferritin change was observed in 51% of the patients. In 15 non-splenectomized patients, liver iron significantly increased from 1260 to 1937 microg/g(liver) (P < 0.01), but serum ferritin remained stable at 2100 microg/l, as did the spleen iron concentration at 1200 microg/g(spleen). A two-compartment model may predict an average chelation efficacy for desferrioxamine and deferiprone, with a saturation effect of the latter, for a certain chelation and transfusion regimen by a single liver iron quantification.

Adolescent↗

Deferiprone therapy in homozygous human beta-thalassemia removes erythrocyte membrane free iron and reduces KCl cotransport activity.

Deposition of free iron is a characteristic feature of beta-thalassemia (beta-thal) red blood cells believed to play an important role in the generation of oxidative injury to the cell membrane. Increased red blood cell KCI cotransport, reduced K content, and cell dehydration are also found in beta-thal red blood cells. It is not known, however, whether deposition of free iron plays a role in these membrane transport changes. To explore this issue, we studied-both in vitro and in vivo-the effect on KCI cotransport of removing red blood cell membrane free iron from beta-thal erythrocytes. Eleven patients with beta-thal major who underwent long-term transfusion and were treated with deferiprone (75 mg/kg/day) for 9 months participated in the study. Deferiprone therapy removed membrane free iron from beta-thal erythrocytes, which was followed by reduced KCI cotransport activity. The reduced KCI cotransport activity was accompanied by an increase in the red blood cell K content. These data suggest that the increased activity of KCI cotransport in beta-thal red blood cells is mediated by the deposition of membrane free iron, a mechanism that may be attenuated by deferiprone therapy.

Adolescent↗

Effects on Mycobacterium avium replication in normal human macrophages by deferiprone (L1) and other iron chelators. Possible implications on toxicity.

Mycobacterium avium growth in cultured human macrophages is influenced by serum lipids, transferrin and iron levels. Iron-saturated transferrin enhances M. avium growth, whereas apotransferrin inhibits mycobacterial replication. The ability of iron chelators to mimic the effects of transferrin on intracellular and extracellular M. avium growth was examined. Smooth, transparent, AIDS patient derived M. avium 7497 scrovar 4 was used to infect 7-day cultured human macrophages. Growth was measured by determining the colony-forming units (CFU) after infected macrophages were lysed 0 to 7 days after infection. The new iron chelating drug deferiprone (1,2-dimethyl-3-hydroxypyrid-4-one or L1, CAS 30652-11-0), 1-ethyl-2-methyl-3-hydroxypyrid-4-one (L1NEt), 1-propyl-2-methyl-3-hydroxypyrid-4-one (L1NPr), 1-allyl-2-methyl-3-hyproxypyrid-4-one (L1NAll), and 3,4-dihydroxycinnamic acid enhanced intracellular and extracellular mycobacterial replication at concentrations of 0.1-2.5 micrograms/ml. 2-Pyridinecarboxaldehyde-2-quinolylhydrazone (PCQH) inhibited intracellular replication from 0.1-1.0 microgram/ml. Most, but not all of the PCQH-induced intracellular inhibition could be eliminated using iron at concentrations greater than 1.0 microgram/ml. Iron also suppressed the effects of PCQH on extracellular M. avium replication. These results indicate that iron chelators may have variable effects at different concentrations and can significantly alter both intracellular and extracellular M. avium replication. It is suggested that at low concentrations deferiprone and other aketohydroxypyridine chelators could enhance the growth of M. avium but at high concentrations may function as adjunct therapy with other antimicrobials against infections with M. avium. These findings are important for therapeutic considerations and dose protocol design in relation to the new iron chelating drug deferiprone, which is currently used in thalassaemia and other iron loaded patients, some of whom are suffering from AIDS.

Cells, Cultured↗

Sequential use of deferiprone and desferrioxamine in primary school children with thalassaemia major in Turkey.

The effectiveness of the sequential use of deferiprone and desferrioxamine (DFO) in children with thalassaemia major was examined. Seven thalassaemic children in whom urinary iron induced by deferiprone was sufficient to maintain a negative iron balance were enrolled in the long-term trial. Deferiprone at a dose of 75 mg/kd/day in 3 divided doses was given for 4 school days a week. The group was given DFO at a dose of 40-50 mg/kg/day s.c. over 8-12 h with a battery-operated pump for 2 days at the weekend. In addition to the safety variables, they were monitored for serum ferritin levels at 2-month intervals and hepatic iron concentrations in liver tissues were determined at the beginning and the 6th month of therapy. The severity of hepatic damage was graded according to the Knodell hepatic activity index and the fibrosis was quantified. None of the patients suffered adverse effects of the therapy but a transient increase in serum ALT levels was noted. A nonsignificant decline in serum ferritin was observed (p = 0.08), a significant reduction in hepatic iron concentration was also determined (p = 0. 03). The hepatic activity index in liver tissues of the patients at the 6th month of the sequential therapy significantly decreased (p = 0.03) whereas fibrosis scores did not differ significantly (p = 0. 25).

Adolescent↗

Long-term therapy with deferiprone.

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.

Animals↗

Oral chelators deferasirox and deferiprone for transfusional iron overload in thalassemia major: new data, new questions.

For nearly 30 years, patients with transfusional iron overload have depended on nightly deferoxamine infusions for iron chelation. Despite dramatic gains in life expectancy in the deferoxamine era for patients with transfusion-dependent anemias, the leading cause of death for young adults with thalassemia major and related disorders has been cardiac disease from myocardial iron deposition. Strategies to reduce cardiac disease by improving chelation regimens have been of the highest priority. These strategies have included development of novel oral iron chelators to improve compliance, improved assessment of cardiac iron status, and careful epidemiologic assessment of European outcomes with deferiprone, an oral alternative chelator available for about a decade. Each of these strategies is now bearing fruit. The novel oral chelator deferasirox was recently approved by the Food and Drug Administration (FDA); a randomized clinical trial demonstrates that deferasirox at 20 to 30 mg/kg/d can maintain or improve hepatic iron in thalassemia as well as deferoxamine. A randomized trial based on cardiac T2* magnetic resonance imaging (MRI) suggests that deferiprone can unload myocardial iron faster than deferoxamine. Retrospective epidemiologic data suggest dramatic reductions in cardiac events and mortality in Italian subjects exposed to deferiprone compared with deferoxamine. These developments herald a new era for iron chelation, but many unanswered questions remain.

Administration, Oral↗

Deferiprone: New insight.

Recent results from independent studies suggest that deferiprone is more cardioprotective than deferoxamine. Patients on long-term treatment with deferiprone have a better myocardial magnetic resonance imaging pattern and less chance to develop a new cardiac disease or worsen an existing one. Most of these observations are retrospective and require confirmation from randomized controlled trials. Other new observations regard the effects of combining the two chelators. Most results indicate an additional effect on iron excretion and a significant reduction of the time required to mitigate severe iron overload and to reverse clinical heart disease. Again, these data require confirmation, as they were mostly obtained on individual cases or small groups of patients treated with a wide range of combinations of the two chelators, but the univocity of results is impressive. After many years of controversy, deferiprone is emerging as a useful oral iron chelator that enhances the chances for the patient to have optimal treatment. Well-designed and -conducted studies will help in answering the questions still open.

Agranulocytosis↗

The design and development of deferiprone (L1) and other iron chelators for clinical use: targeting methods and application prospects.

Iron is essential for all human cells as well as neoplastic cells and invading microbes. Natural and synthetic iron chelators could affect biological processes involving iron and other metal ions in health and disease states. Iron overload is the most common metal toxicity condition worldwide. There are currently two iron chelating drugs, which are mostly used for the treatment of thalassaemia and other conditions of transfusional iron overload. Deferoxamine was until recently the only approved iron chelating drug, which is effective but very expensive and administered parenterally resulting in low compliance. Deferiprone (L1 or 1,2-dimethyl-3-hydroxypyrid-4-one) is the world's first and only orally active iron chelating drug, which is effective and inexpensive to synthesise thus increasing the prospects of making it available to most thalassaemia patients in third world countries who are not currently receiving any form of chelation therapy. Deferiprone has equivalent iron removal efficacy and comparable toxicity to deferoxamine. There are at least four other known iron chelators, which are currently being developed. Even if successful, these are not expected to become available for clinical use in the next five years and to be as inexpensive as deferiprone. The variation in the chemical, biological, pharmacological, toxicological and other properties of the chelating drugs and experimental chelators provide evidence of the difference in the mode of action of chelators and the need to identify and select molecular structures and substituents based on structure/activity correlations for specific pharmacological activity. Such information may increase the prospects of designing new chelating drugs, which could be targeted and act on different tissues, organs, proteins and iron pools that play important role not only in the treatment of iron overload but also in other diseases of iron and other metal imbalace and toxicity including free radical damage. Chelating drugs could also be designed, which could modify the enzymatic activity of iron and other metal containing enzymes, some of which play a key role in many diseases such as cancer, inflammation and atherosclerosis. Other applications of iron chelating drugs could involve the detoxification of toxic metals with similar metabolic pathways to iron such as Al, Cu, Ga, In, U and Pu.

Animals↗