Approaching low liver iron burden in chelated patients with non-transfusion-dependent thalassemia: the safety profile of deferasirox

OBJECTIVE

Patients with non-transfusion-dependent thalassemia (NTDT) often develop iron overload and related complications, and may require iron chelation. However, the risk of over-chelation emerges as patients reach low, near-normal body iron levels and dose adjustments may be needed. In the THALASSA study, the threshold for chelation interruption was LIC <3 mg Fe/g dw (LIC<3); 24 patients receiving deferasirox for up to 2 yr reached this target. A post hoc analysis was performed to characterize the safety profile of deferasirox as these patients approached LIC<3.

METHODS

THALASSA was a randomized, double-blind, placebo-controlled study of two deferasirox regimens (5 and 10 mg/kg/d) versus placebo in patients with NTDT. Patients randomized to deferasirox or placebo in the core could enter a 1-yr extension, with all patients receiving deferasirox (extension starting doses based on LIC at end-of-core and prior chelation response). The deferasirox safety profile was assessed between baseline and 6 months before reaching LIC<3 (Period 1), and the 6 months immediately before achieving LIC<3 (Period 2).

RESULTS

Mean ± SD deferasirox treatment duration up to reaching LIC<3 was 476 ± 207 d, and deferasirox dose was 9.7 ± 3.0 mg/kg/d. The exposure-adjusted AE incidence regardless of causality was similar in periods 1 (1.026) and 2 (1.012). There were no clinically relevant differences in renal and hepatic laboratory parameters measured close to the time of LIC<3 compared with measurements near the previous LIC assessment.

CONCLUSIONS

The deferasirox safety profile remained consistent as patients approached the chelation interruption target, indicating that, with appropriate monitoring and dose adjustments in relation to iron load, low iron burdens may be reached with deferasirox with minimal risk of over-chelation.

Once-daily oral deferasirox for the treatment of transfusional iron overload

The increasing use of blood transfusions, combined with extended patient survival, has led to an increase in the number of patients at risk of developing transfusional iron overload. Clinical data have shown that the once-daily oral iron chelator deferasirox is effective in adults and children with various transfusion-dependent anemias, including β-thalassemia and the myelodysplastic syndromes. Deferasirox has a defined, clinically manageable safety profile. The most common treatment-related adverse events are mild gastrointestinal disorders, skin rash and mild, nonprogressive serum creatinine increases. The deferasirox clinical trial program is continuing in Phase II/III extension phases and Phase IV trials. Long-term data continue to support the efficacy and safety of deferasirox. Convenient, effective and tolerable chelation therapy with deferasirox is a significant development in the treatment of transfusional iron overload.

Impact of heart magnetic resonance imaging on chelation choices, compliance with treatment and risk of heart disease in patients with thalassaemia major

This study aimed to verify the impact of heart magnetic resonance imaging on chelation choices and patient compliance in a single-institution cohort as well as its predictive value for heart failure and arrhythmias. Abnormal cardiac T2* values determined changes in treatment in most subjects. Heart T2* was confirmed to be highly predictive over 1 year for heart failure and arrhythmias. The choice of chelation regimens known to remove heart iron efficiently was not sufficient by itself to influence the risk. Compliance with treatment had a more remarkable role.

Longitudinal analysis of heart and liver iron in thalassemia major patients according to chelation treatment

Iron chelators and nuclear magnetic resonance imaging (MRI) techniques for assessing iron loading in liver and heart have greatly improved survival of thalassemic patients suffering iron overload-associated cardiomyopathy. However, the correlation between liver iron concentration and myocardial siderosis is ambiguous. Using an objective metric of time delay, scientists have demonstrated a lag in the loading and unloading of cardiac iron with respect to that of the liver. In the present study, we further tested this hypothesis with different chelation treatments. We analyzed the effect of three chelating treatment approaches on liver and cardiac iron content in 24 highly compliant patients who underwent 3 or more MRIs under each chelation treatment. Of the 84 MRIs considered, 32 were performed on deferoxamine (DFO - 8 patients), 24 on deferiprone (DFP - 7 patients), and 28 on combined therapy (DFO+DFP - 9 patients). In patients treated with DFO, changes in cardiac iron significantly lagged changes in liver iron but the opposite pattern was observed in patients treated with DFP (p=0.005), while combined therapy showed a pattern in-between DFO and DFP. We conclude that the temporality of changes of cardiac and liver iron is chelator-dependent, so that chelation therapy can be tailored to balance iron elimination from the liver and the heart.

Natural history of hepatitis C in thalassemia major: a long-term prospective study

BACKGROUND

Transfusion-acquired hepatitis C virus (HCV) remains an important problem among patients with thalassemia. In this study, we evaluated the natural history of post-transfusional hepatitis C in thalassemia major, paying special attention to spontaneous viral clearance, to factors influencing the chronicity rate and fibrosis progression.

DESIGN AND METHODS

A prospective study to evaluate the incidence and etiology of transfusion-related hepatitis was started in 1980. In patients who developed hepatitis C, HCV RNA, ALT, and ferritin were measured over time. The correlation between interleukin-28B gene polymorphisms and viral clearance was also analyzed.

RESULTS

Seventy-three of 135 patients (62.2%) acquired HCV. An extended follow-up (22 to 30 yr) with HCV RNA assessment was available in 52 patients. Of them, 23 (44.2%) cleared the virus. The proportion of IL-28B genotypes was different between the subjects who cleared the virus and the subjects who did not. Fibrosis progression was similar in HCV RNA-positive and HCV RNA-negative patients. Liver iron was the only factor associated with the fibrosis.

CONCLUSIONS

In thalassemia patients with HCV infection, liver iron does not play a major role in influencing the chronicity rate, whereas it is significantly associated with the fibrosis.

Pathophysiology of beta thalassaemia

In beta thalassemia, unbalanced alpha globin chain synthesis results in severely rheologically compromised erythrocytes with premature destruction in the peripheral circulation and ineffective erythropoiesis within the bone marrow and in extramedullary sites. In nontransfused beta thalassemia patients, erythropoiesis,anemia and hypoxia down-regulate hepcidin, the master regulator of iron homeostasis. Hepcidin deficiency in turn allows excessive duodenal iron absorption and development of systemic iron overload. In regularly transfused patients iron overload is mostly due to red cell breakdown. When the iron binding capacity of transferrin is saturated, iron can appear in the serum in a free form, called Non-Transferrin-Bound Iron, a powerful catalyst for the formation of free radicals, capable of causing oxidative stress and damage to mitochondria, lysosomes, lipid membranes, proteins, and DNA. Apart from the iron overload-related complications, other pathological conditions such as bone disease, gallstones and thromboembolic events occur in a relevant proportion of subjects with thalassemia.

Beta-thalassemia

Beta-thalassemias are a group of hereditary blood disorders characterized by anomalies in the synthesis of the beta chains of hemoglobin resulting in variable phenotypes ranging from severe anemia to clinically asymptomatic individuals. The total annual incidence of symptomatic individuals is estimated at 1 in 100,000 throughout the world and 1 in 10,000 people in the European Union. Three main forms have been described: thalassemia major, thalassemia intermedia and thalassemia minor. Individuals with thalassemia major usually present within the first two years of life with severe anemia, requiring regular red blood cell (RBC) transfusions. Findings in untreated or poorly transfused individuals with thalassemia major, as seen in some developing countries, are growth retardation, pallor, jaundice, poor musculature, hepatosplenomegaly, leg ulcers, development of masses from extramedullary hematopoiesis, and skeletal changes that result from expansion of the bone marrow. Regular transfusion therapy leads to iron overload-related complications including endocrine complication (growth retardation, failure of sexual maturation, diabetes mellitus, and insufficiency of the parathyroid, thyroid, pituitary, and less commonly, adrenal glands), dilated myocardiopathy, liver fibrosis and cirrhosis). Patients with thalassemia intermedia present later in life with moderate anemia and do not require regular transfusions. Main clinical features in these patients are hypertrophy of erythroid marrow with medullary and extramedullary hematopoiesis and its complications (osteoporosis, masses of erythropoietic tissue that primarily affect the spleen, liver, lymph nodes, chest and spine, and bone deformities and typical facial changes), gallstones, painful leg ulcers and increased predisposition to thrombosis. Thalassemia minor is clinically asymptomatic but some subjects may have moderate anemia. Beta-thalassemias are caused by point mutations or, more rarely, deletions in the beta globin gene on chromosome 11, leading to reduced (beta⁺) or absent (beta⁰) synthesis of the beta chains of hemoglobin (Hb). Transmission is autosomal recessive; however, dominant mutations have also been reported. Diagnosis of thalassemia is based on hematologic and molecular genetic testing. Differential diagnosis is usually straightforward but may include genetic sideroblastic anemias, congenital dyserythropoietic anemias, and other conditions with high levels of HbF (such as juvenile myelomonocytic leukemia and aplastic anemia). Genetic counseling is recommended and prenatal diagnosis may be offered. Treatment of thalassemia major includes regular RBC transfusions, iron chelation and management of secondary complications of iron overload. In some circumstances, spleen removal may be required. Bone marrow transplantation remains the only definitive cure currently available. Individuals with thalassemia intermedia may require splenectomy, folic acid supplementation, treatment of extramedullary erythropoietic masses and leg ulcers, prevention and therapy of thromboembolic events. Prognosis for individuals with beta-thalassemia has improved substantially in the last 20 years following recent medical advances in transfusion, iron chelation and bone marrow transplantation therapy. However, cardiac disease remains the main cause of death in patients with iron overload.

Pregnancy and beta-thalassemia: an Italian multicenter experience

BACKGROUND

Recent advances in the management of thalassemia have significantly improved life expectancy and quality of life of patients with this hemoglobinopathy, with a consequent increase in their reproductive potential and desire to have children.

DESIGN AND METHODS

We describe the methods of conception and delivery, as well as the course and outcome of pregnancy including transfusions, iron overload and chelation in 46 women with thalassemia major (58 pregnancies) and in 11 women with thalassemia intermedia (17 pregnancies). Conception was achieved after gonadotrophin-induced ovulation in 33 of the women with thalassemia major and spontaneously in all of those with thalassemia intermedia.

RESULTS

Among the women with thalassemia major, 91% of the pregnancies resulted in successful delivery of 45 singleton live-born neonates, five sets of twins and one set of triplets. No secondary complications of iron overload developed or worsened during pregnancy. When considering only the singleton pregnancies, the proportion of babies with intrauterine growth retardation did not differ from that reported in the general Italian population. The high prevalence of pre-term births (32.7%) was mostly related to multiple pregnancies and precautionary reasons. Pregnancy was safe in most women with thalassemia major or intermedia. However, women with thalassemia intermedia who had never previously been transfused or who had received only minimal transfusion therapy were at risk of severe alloimmune anemia if blood transfusions were required during pregnancy.

CONCLUSIONS

Provided that a multidisciplinary team is available, pregnancy is possible, safe and usually has a favorable outcome in patients with thalassemia. In women with hypogonadotropic hypogonadism, gonadal function is usually intact and fertility is usually retrievable.

Cholelithiasis in thalassemia major

OBJECTIVES

Aim of this study was to evaluate prevalence and characteristics of cholelithiasis in a large population of patients with thalassemia major (TM).

METHODS

Data from 858 consecutive patients with transfusion-dependent thalassemia at five major Italian centers were analyzed. In these centers, a complete abdomen ultrasonography is performed yearly after the beginning of the transfusion regimen. The role of co-inheriting Gilbert's syndrome genotype was investigated studying the promoter region of the UGT1-A1 gene by automated sequencing.

RESULTS

Thirty percent of TM patients had gallstones. The Gilbert's genotype [homozygosity for (TA)(7) motif at UGT1A promoter gene], influenced both the prevalence of cholelithiasis and the age at which it developed.

CONCLUSIONS

Cholelithiasis has a remarkable frequency and precocity in patients with TM and especially in those with (TA)(7)/(TA)(7) UGT1-A1 genotype. An early biliary ultrasonography is recommended from childhood and a closer follow-up in patients with thalassemia and associated Gilbert's syndrome may be indicated.

Onset of cardiac iron loading in pediatric patients with thalassemia major

We reviewed cardiac T2* assessments from 77 thalassemia major patients between the ages of 2.5 and 18 years to study optimal timing of cardiac iron screening by magnetic resonance imaging. No patient under 9.5 years of age showed detectable cardiac iron in contrast to 36% of patients between the ages of 15-18 years old, corresponding to an odds-ratio of 1.28 (28%) per year. All patients with cardiac iron had received at least 35 grams of transfusional iron. Liver iron and ferritin failed to predict cardiac iron loading. Initiation of cardiac magnetic resonance imaging assessment should be determined according to age and transfusional burden rather than indices of iron overload. When appropriate chelation therapy has been administered since birth, cardiac magnetic resonance imaging can be postponed until 8 years of age when anesthesia is not required. Patients with suboptimal chelation, increased transfusional requirements, or who have initiated transfusions later in life should be tested sooner.

Liver iron concentrations and urinary hepcidin in beta-thalassemia

BACKGROUND AND OBJECTIVES

Patients with beta-thalassemia, like those with genetic hemochromatosis, develop iron overload due to increased iron absorption, and their iron burden is further exacerbated by transfusion therapy. Hepcidin, a hepatic hormone, regulates systemic iron homeostasis by inhibiting the absorption of iron from the diet and the recycling of iron by macrophages. In turn, hepcidin release is increased by iron loading and inhibited by erythropoietic activity. Hepcidin deficiency is the cause of iron overload in most forms of hereditary hemochromatosis. We sought to determine hepcidin's role in the pathogenesis of iron overload in b-thalassemia.

DESIGN AND METHODS

We assessed the degree of iron overload in thalassemia intermedia and major patients by measuring hepatic iron concentration in liver biopsy samples and serum ferritin, estimated erythropoietic drive by assaying soluble transferrin receptor and serum erythropoietin levels and correlated these with urinary hepcidin measurements.

RESULTS

Urinary hepcidin levels in beta-thalassemia demonstrate severe hepcidin deficiency in thalassemia intermedia. There was a strong inverse relationship between urinary hepcidin levels and both erythropoietin and soluble transferrin receptor, markers of erythropoietic activity. In contrast, hepcidin levels were elevated in thalassemia major, presumably due to transfusions that reduce erythropoietic drive and deliver a large iron load. Despite similar liver iron concentrations in the two conditions, serum ferritin was much lower in thalassemia intermedia.

INTERPRETATION AND CONCLUSIONS

In thalassemia intermedia, high erythropoietic drive causes severe hepcidin deficiency. The lack of hepcidin results in hyperabsorption of dietary iron, but also in iron depletion of macrophages, lowering their secretion of ferritin and, consequently, serum ferritin levels. In contrast, in thalassemia major, transfusions decrease erythropoietic drive and increase the iron load, resulting in relatively higher hepcidin levels. In the presence of higher hepcidin levels, dietary iron absorption is moderated and macrophages retain iron, contributing to higher serum ferritin. In the future, hepcidin measurements may allow a more accurate assessment of the degree of iron overload and the maldistribution of iron in thalassemia.

Clinical and molecular analysis of haemoglobin H disease in Sardinia: haematological, obstetric and cardiac aspects in patients with different genotypes

In this study, 251 Sardinian patients (187 adults and 64 children) with haemoglobin (Hb) H disease were evaluated. Two-hundred and sixteen patients (86%) had the deletional type (- -/-alpha) and 36 (14%) patients had the non-deletional type (- -/alpha(ND)alpha). A clear genotype-phenotype correlation was found, with the non-deletional type more severe than the deletional type. Diagnosis of Hb H disease was incidental in about 60% of cases. Aplastic crises due to B19 parvovirus infection were found in five patients (2.1%), while 23 patients (9.6%) experienced one or more haemolytic crises. Nineteen patients with Hb H received sporadic red blood cell transfusions and three patients were repeatedly transfused. Forty-seven of 61 married women (77%) had 82 pregnancies. In children, mean serum ferritin was 87 +/-92 mug/l and in adults, was 192 +/- 180 mug/l in females and 363 +/- 303 mug/l in males. For the 98 male patients, a significant correlation was found between ferritin values and age (r2 = 0.33, P < 0.0001). In the Sardinian population, Hb H disease needs regular monitoring for early detection and treatment of possible complications, such as worsening of anaemia that may require red cell transfusion, cholelithiasis and iron overload.

Randomized phase II trial of deferasirox (Exjade, ICL670), a once-daily, orally-administered iron chelator, in comparison to deferoxamine in thalassemia patients with transfusional iron overload

BACKGROUND AND OBJECTIVES

Iron accumulation is an inevitable consequence of chronic blood transfusions and results in serious complications in the absence of chelation treatment to remove excess iron. Deferoxamine (Desferal, DFO) reduces morbidity and mortality although the administration schedule of slow, parenteral infusions several days each week limits compliance and negatively affects long-term outcome. Deferasirox (Exjade, ICL670) is an oral chelator with high iron-binding potency and selectivity. In a phase II study, the tolerability and efficacy of deferasirox were compared with those of DFO in 71 adults with transfusional hemosiderosis.

DESIGN AND METHODS

Patients were randomized to receive once-daily deferasirox (10 or 20 mg/kg; n=24 in both groups) or DFO (40 mg/kg, 5 days/week; n=23) for 48 weeks. Results. Both treatments were well tolerated and no patient discontinued deferasirox due to drug-related adverse events. The reported frequency of transient, mild to moderate gastrointestinal disturbances was higher in the deferasirox group than in the DFO group, but these disturbances settled spontaneously without dose interruption in all patients. Decreases in liver iron concentration (LIC) were comparable in the deferasirox 20 mg/kg/day and DFO groups; baseline values of 8.5 and 7.9 mg Fe/g dw fell to 6.6 and 5.9 mg Fe/g dw, respectively, by week 48. Deferasirox showed a plasma elimination half-life of 8-16 hours, supporting its once-daily administration.

INTERPRETATION AND CONCLUSIONS

Deferasirox at daily doses of 10 or 20 mg/kg was well tolerated and, at 20 mg/kg, showed similar efficacy to DFO 40 mg/kg in terms of decreases in LIC.

Seasonal variation of pretransfusion hemoglobin levels in patients with thalassemia major

Patients with thalassemia major often report that they do not maintain their usual pretransfusion hemoglobin concentration during the summer season. We collected 3977 pretransfusion hemoglobin values, amount of blood transfused, and intertransfusion intervals for 94 patients with thalassemia major from 4 centers worldwide. We also assessed the hematocrits of blood donors, the hemoglobin content of units transfused in one center, and the local mean monthly temperatures during the periods of data collection. Pretransfusion hemoglobin levels were significantly lower during the summer in all centers except the one center where monthly temperatures have the least variation throughout the year. A similar relationship to temperature was observed for the hematocrits of blood donors and the hemoglobin content of donor units. This study confirms that pretransfusion hemoglobin levels in patients with thalassemia major are lower in the summertime. Possible mechanisms include expansion of plasma volume with resultant hemodilution in the patient and lower hemoglobin content in donor blood.

Survival and Complications in Thalassemia

The life expectancy of patients with thalassemia major has significantly increased in recent years, as reported by several groups in different countries. However, complications are still frequent and affect the patients' quality of life. In a recent study from the United Kingdom, it was found that 50% of the patients had died before age 35. At that age, 65% of the patients from an Italian long-term study were still alive. Heart disease is responsible for more than half of the deaths. The prevalence of complications in Italian patients born after 1970 includes heart failure in 7%, hypogonadism in 55%, hypothyroidism in 11%, and diabetes in 6%. Similar data were reported in patients from the United States. In the Italian study, lower ferritin levels were associated with a lower probability of experiencing heart failure and with prolonged survival. Osteoporosis and osteopenia are common and affect virtually all patients. Hepatitis C virus antibodies are present in 85% of multitransfused Italian patients, 23% of patients in the United Kingdom, 35% in the United States, 34% in France, and 21% in India. Hepatocellular carcinoma can complicate the course of hepatitis. A survey of Italian centers has identified 23 such cases in patients with a thalassemia syndrome. In conclusion, rates of survival and complication-free survival continue to improve, due to better treatment strategies. New complications are appearing in long-term survivors. Iron overload of the heart remains the main cause of morbidity and mortality.

Osteoporosis in β-Thalassemia: Clinical and Genetic Aspects

Osteoporosis and osteopenia are frequent complications of thalassemia major (TM) and intermedia (TI). Osteoporosis was found in 23/25 patients with TI and in 115/239 patients with TM. In TM, no association was found with specific polymorphisms in candidate genes (vitamin D receptor, estrogen receptor, calcitonin receptor, and collagen type 1 alpha 1). Osteoporosis in female patients with TM was strongly associated with primary amenorrhea (P < .0001), while in male patients with TM, hypogonadism was not significantly related to bone mineral density (BMD) (P = .0001). Low BMD was also associated with cardiomiopathy (P = .01), diabetes mellitus (P = .0001), chronic hepatitis (P = .0029), and increased ALT (P = .01).

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.

[Relation between hypogonadism and malocclusion in beta-thalassemia major patients: analysis of 122 subjects]

AIM

The type of malocclusion most often seen in beta thalassemic patients is represented by Angle's II class, which however cannot be considered significant in the patients studied in this research. The only causal factor indicated by medical literature for this pathology is medullary hyperplasia due to inefficient erythropoiesis which occurs in patients transfused at low hemoglobin levels. The aim of this research is to evaluate the influence of other factors as well, particularly sexual development, the level of seric ferritin, ALT, and age at first transfusion.

METHODS

One-hundred and twenty-two b thalassemic patients and 39 homozygotes, aged between 16 and 27, undergoing treatment at the "Ospedale Regionale per le Microcitemie di Cagliari", have been analysed.

RESULTS

The results of the statistic analysis have shown that hypogonadism can play an important role in determining malocclusions in male beta thalassemic patients (Odds ratio 4,5; CI 1,5-13). No other factor has shown any statistically relevant influence on dental occlusion.

CONCLUSION

It would therefore be interesting to further investigate the hormonal mechanisms that can alter bone development in thalassemic youngsters: the prevention of such alterations will surely contribute to improving the quality of life in these patients, particularly now that their life expectancy has been significantly extended by the progress made in transfusional therapy and ferrochelation.