Carlo Dessì

A Randomized, Placebo-Controlled, Double-Blind Trial of the Effect of Combined Therapy With Deferoxamine and Deferiprone on Myocardial Iron in Thalassemia Major Using Cardiovascular Magnetic Resonance

Background— Cardiac complications secondary to iron overload are the leading cause of death in &bgr;-thalassemia major. Approximately two thirds of patients maintained on the parenteral iron chelator deferoxamine have myocardial iron loading. The oral iron chelator deferiprone has been demonstrated to remove myocardial iron, and it has been proposed that in combination with deferoxamine it may have additional effect. Methods and Results— Myocardial iron loading was assessed with the use of myocardial T2* cardiovascular magnetic resonance in 167 patients with thalassemia major receiving standard maintenance chelation monotherapy with subcutaneous deferoxamine. Of these patients, 65 with mild to moderate myocardial iron loading (T2* 8 to 20 ms) entered the trial with continuation of subcutaneous deferoxamine and were randomized to receive additional oral placebo (deferoxamine group) or oral deferiprone 75 mg/kg per day (combined group). The primary end point was the change in myocardial T2* over 12 months. Secondary end points of endothelial function (flow-mediated dilatation of the brachial artery) and cardiac function were also measured with cardiovascular magnetic resonance. There were significant improvements in the combined treatment group compared with the deferoxamine group in myocardial T2* (ratio of change in geometric means 1.50 versus 1.24; P=0.02), absolute left ventricular ejection fraction (2.6% versus 0.6%; P=0.05), and absolute endothelial function (8.8% versus 3.3%; P=0.02). There was also a significantly greater improvement in serum ferritin in the combined group (−976 versus −233 &mgr;g/L; P<0.001). Conclusions— In comparison to the standard chelation monotherapy of deferoxamine, combination treatment with additional deferiprone reduced myocardial iron and improved the ejection fraction and endothelial function in thalassemia major patients with mild to moderate cardiac iron loading.

Combined chelation therapy in thalassemia major for the treatment of severe myocardial siderosis with left ventricular dysfunction

BackgroundIn thalassemia major (TM), severe cardiac siderosis can be treated by continuous parenteral deferoxamine, but poor compliance, complications and deaths occur. Combined chelation therapy with deferiprone and deferoxamine is effective for moderate myocardial siderosis, but has not been prospectively examined in severe myocardial siderosis.MethodsT2* cardiovascular magnetic resonance (CMR) was performed in 167 TM patients receiving standard subcutaneous deferoxamine monotherapy, and 22 had severe myocardial siderosis (T2* < 8 ms) with impaired left ventricular (LV) function. Fifteen of these patients received combination therapy with subcutaneous deferoxamine and oral deferiprone with CMR follow-up.ResultsAt baseline, deferoxamine was prescribed at 38 ± 10.2 mg/kg for 5.3 days/week, and deferiprone at 73.9 ± 4.0 mg/kg/day. All patients continued both deferiprone and deferoxamine for 12 months. There were no deaths or new cardiovascular complications. The myocardial T2* improved (5.7 ± 0.98 ms to 7.9 ± 2.47 ms; p = 0.010), with concomitant improvement in LV ejection fraction (51.2 ± 10.9% to 65.6 ± 6.7%; p < 0.001). Serum ferritin improved from 2057 (CV 7.6%) to 666 (CV 13.2%) μg/L (p < 0.001), and liver iron improved (liver T2*: 3.7 ± 2.9 ms to 10.8 ± 7.3 ms; p = 0.006).ConclusionIn patients with severe myocardial siderosis and impaired LV function, combined chelation therapy with subcutaneous deferoxamine and oral deferiprone reduces myocardial iron and improves cardiac function. This treatment is considerably less onerous for the patient than conventional high dose continuous subcutaneous or intravenous deferoxamine monotherapy, and may be considered as an alternative. Very prolonged tailored treatment with iron chelation is necessary to clear myocardial iron, and alterations in chelation must be guided by repeated myocardial T2* scans.Trial registrationThis trial is registered as NCT00103753

Myocardial Iron Loading in Patients with Thalassemia Major on Deferoxamine Chelation

BACKGROUND Heart failure secondary to myocardial iron loading remains the leading cause of death in thalassemia major (TM). We used cardiovascular magnetic resonance (CMR) to assess the prevalence of myocardial iron overload and ventricular dysfunction in a large cohort of TM patients maintained on conventional chelation treatment with deferoxamine. METHODS A mobile CMR scanner was transported from London, UK, to Sardinia, Italy where 167 TM patients were assessed for myocardial iron loading, B-natriuretic peptide (BNP), and ferritin. In patients with myocardial iron loading CMR assessments of ventricular function were also made. RESULTS Myocardial iron loading (T2* < 20 ms) was present in 108 (65%) patients, which was severe (T2* < 8 ms) in 22 (13%). Impaired (< 56%) left ventricular (LV) ejection fraction (EF) was present in 5%, 20% and 62% of patients with mild, moderate or severe iron loading. Increasing myocardial iron was related to impaired LVEF (Rs = 0.57, p < 0.001), weakly related to serum ferritin (Rs = -0.34, p < 0.001), and not related to liver iron (Rs = 0.11, p = 0.26). BNP was weakly related to myocardial iron (Rs = -0.35, p < 0.001) and was abnormal in only 5 patients. CONCLUSIONS Myocardial siderosis was found in two-thirds of thalassemia major patients on maintenance deferoxamine treatment. This was combined with a high prevalence of impaired LV function, the severity of which tracked the severity of iron deposition. BNP was not useful to assess myocardial siderosis.

Relationship between transfusion regimen and suppression of erythropoiesis in β-thalassaemia major

In the management of β‐thalassaemia major, different transfusion schemes are employed with baseline haemoglobin levels ranging from 8 to over 12 g/dl. We studied the relationship between transfusion regimen and suppression of erythropoiesis in 52 patients with β‐thalassaemia major whose mean pretransfusion haemoglobin levels ranged from 8.6 to 10.9 g/dl. Multiple, regression analysis showed that serum transferrin receptor was the parameter more closely related to mean pretransfusion haemoglobin (r = ‐0.77, P < 0.001). As measured through serum transferrin receptor, erythroid activity was 1‐2 times normal for pretransfusion haemoglobin levels between 10 and 11 g/dl, 1‐4 times normal for levels from 9 to 10 g/dl, and 2‐6 times normal for levels from 8.6 to 9 g/dl. Mean pretransfusion haemoglobin was also inversely related to serum erythropoietin (r = ‐0.72, P < 0.001), whereas it showed no or a weak relationship with Hb F, reticulocyte count, or circulating nucleated red cell count. This study suggests that serum transferrin receptor is a reliable indicator of suppression of erythropoiesis in β‐thalassaemia major. On the basis of our findings, pretransfusion haemoglobin values of ≦ 9 g/dl should be adopted with caution, because these levels can be associated with an insufficient inhibition of erythroid marrow expansion. However, a transfusion programme, with a baseline haemoglobin of 9‐10 g/dl, may provide enough suppression of erythropoiesis and allow a reduction in blood consumption as compared with the classic hyper‐ or supertransfusion schemes. Since fixed haemoglobin levels may not be the best target for transfusion treatment in all thalassaemic patients, assay of serum transferrin receptor may be helpful for individualizing the transfusion regimens.

Serum ferritin, desferrioxamine, and evolution of HIV-1 infection in thalassemic patients.

To study the respective roles of mean serum ferritin level and the mean desferrioxamine (DFX) dose on progression of HIV-1 infection, data from 49 HIV-seropositive thalassemic patients were analyzed using a Cox proportional hazards model including known confounding variables. Nine years after seroconversion, 10% of those who had been prescribed >40 mg/kg of DFX daily had entered stage IV versus 39% of those who had been prescribed a lower dose. Patients with ferritin level >1935 g/L entered stage IV more rapidly than those with a lower level (31% versus 16%). In multivariate analysis, the ferritin level was found to be an independent predictor of progression of HIV disease, whereas the mean daily dose of DFX was not. Similar results were obtained when death was the endpoint. Our results support a hypothesis that was recently expressed, that iron overload could be associated with a more rapid progression of HIV-1 infection.

Dose of desferrioxamine and evolution of HIV-1 infection in thalassaemic patients.

To study the relationship between the dose of desferrioxamine (DFX) and the progression of the HIV‐1 disease in thalassaemia major patients (TMP), 64 seropositive TMP patients were studied. Cumulative incidence of CDC stage IV was calculated using a non‐parametric life‐table method. The association with the mean daily dose of DFX was tested with a Cox proportional hazards model which was also used to adjust for confounding variables. The median of the mean daily dose of DFX over the seropositive period was 40mg/kg (range 0‐65mg/kg). Age at seroconversion (P < 0.02) and splenectomy (P < 0.03) were found to be associated with the mean daily dose of DFX. 6.5 years after seroconversion, 11% of those who had been prescribed more than 40mg/kg of DFX daily had entered stage IV versus 35% of those who had been prescribed a lower dose (P < 0.01). When the dose was taken as a continuous variable it was found that the rate of progression was significantly smaller in TMP receiving a higher dose (P < 0.002). even after adjusting for age and splenectomy (P < 0.02). Although it should be noted that these results were obtained in an observational study, possibly biased by a non‐random allocation of the DFX dose, we believe that they are striking enough to support the claim that the role of DFX in the progression of HIV disease should be further evaluated.

HbH Disease in Sardinia: Molecular, Hematological and Clinical Aspects

In this study we have defined the molecular basis and correlated the clinical phenotype with the alpha-globin genotype in a large series of patients of Sardinian descent with HbH disease. The most prevalent molecular defect was the deletion of 3 alpha-globin structural genes most commonly the (--/-alpha 3.7) genotype (83.6%) and rarely the (--/-alpha 4.2) genotype (1.4%), followed in decreasing order of incidence by the combination of deletion alpha zero-thalassemia and initiation codon mutation of the alpha 2-gene (--/alpha NcoI alpha = 9.8%), deletion alpha zero-thalassemia and pentanucleotide deletion of IVS-I of the alpha 2-globin gene, (--/alpha HphI alpha = 3.3%) deletion alpha zero-thalassemia and initiation codon mutation of the alpha 1-gene (--/alpha alpha NcoI = 1.3%), a homozygous state for initiation codon mutation of the alpha 2-gene (alpha Nco alpha/alpha NcoI alpha = 0.7%). Patients with the (--/alpha thal alpha) genotypes showed severer clinical and hematological features as compared to those with the (--/-alpha) or those with the (--/alpha alpha thal) genotypes. The single patient with the (alpha Nco alpha/alpha Nco alpha) genotype had a clinical phenotype intermediate between HbH disease and the alpha-thalassemia carrier status. This heterogeneity depends on the fact that the alpha 2-globin gene produces 2-3 times alpha-globin chains than the alpha 1-gene and the single remaining alpha 1-like globin gene in the -alpha 3.7 chromosome has a compensatory increase in the alpha-globin chain output. alpha-Globin gene mapping of HbH disease patients may be useful for predicting the clinical outcome and to improve genetic counseling.

Genetic modifiers of β-thalassemia and clinical severity as assessed by age at first transfusion

Background The clinical and hematologic features of β-thalassemia are modulated by different factors, resulting in a wide range of clinical severity. The main factors are the type of disease-causing mutation and the ability to produce α-globin and γ-globin chains. In the present study we investigated the respective contributions of known modifiers to the prediction of the clinical severity of β-thalassemia as assessed by the patients’ age at first transfusion. Design and Methods We studied the effect of seven loci in a cohort of 316 Sardinian patients with β0-thalassemia. In addition to characterizing the β-globin gene mutations, α-globin gene defects and HBG2:g.−158C>T polymorphism, we genotyped two different markers in the BCL11A gene and three in the HBS1L-MYB intergenic region using single nucleotide polymorphism microarrays, imputation and direct genotyping. We performed Cox proportional hazard analysis of the time to first transfusion. Results According to the resulting model, we were able to explain phenotypic severity to a large extent (Harrell’s concordance index=0.72; Cox & Snell R2=0.394) and demonstrated that most of the model’s discriminatory ability is attributable to the genetic variants affecting fetal hemoglobin production (HBG2:g.−158C>T, BCL11A and HBS1L-MYB loci: C-index=0.68, R2=0.272), while the remaining is due to α-globin gene defects and gender. Consequently, significantly distinct survival curves can be described in our population. Conclusions This detailed analysis clarifies the impact of genetic modifiers on the clinical severity of the disease, measured by time to first transfusion, by determining their relative contributions in a homogeneous cohort of β0-thalassemia patients. It may also support clinical decisions regarding the beginning of transfusion therapy in patients with β-thalassemia.

Toward optimizing the use of deferasirox: potential benefits of combined use with deferoxamine

Patients with β-thalassemia require iron chelation therapy to protect against progressive iron overload and non-transferrin-bound iron. Some patients fail to respond adequately to deferoxamine and deferasirox monotherapy while others have side effects which limit their use of these drugs. Since combining deferiprone and deferoxamine has an additive effect, placing all patients into net negative iron balance, we investigated the possibility that combining deferasirox and deferoxamine would lead to similar results. We conducted 34-day metabolic iron balance studies in six patients in whom the relative effectiveness of deferasirox (30 mg/kg/day) and deferoxamine (40 mg/kg/day) was compared, alone and in combination. Patients consumed fixed low-iron diets; daily urinary and stool iron excretion were determined by atomic absorption. Red blood cell transfusions were given prior to each drug treatment to minimize the effects of ineffective erythropoiesis. Serial safety measures, hematologic parameters, serum chemistries, ferritin levels and urinalyses were determined. All patients were in negative iron balance when treated with deferoxamine alone while four of six patients remained in positive balance when deferasirox monotherapy was evaluated. Daily use of both drugs had a synergistic effect in two patients and an additive effect in three others. Five of six patients would be in negative iron balance if they used the combination of drugs just 3 days a week. No significant or drug-related changes were observed in the blood work-ups or urinalyses performed. We conclude that supplementing the daily use of deferasirox with 2 – 3 days of deferoxamine therapy would place all patients into net negative iron balance thereby providing a convenient way to tailor chelation therapy to the individual needs of each patient.

Effects of combined deferiprone with deferoxamine on right ventricular function in thalassaemia major

BackgroundCombination therapy with deferoxamine and oral deferiprone is superior to deferoxamine alone in removing cardiac iron and improving left ventricular ejection fraction (LVEF). The right ventricle (RV) is also affected by the toxic effects of iron and may cause additional cardiovascular perturbation. We assessed the effects of combination therapy on the RV in thalassaemia major (TM) using cardiovascular magnetic resonance (CMR).MethodsWe retrieved imaging data from 2 treatment trials and re-analyzed the data for the RV responses: Trial 1 was a randomized controlled trial (RCT) of 65 TM patients with mild-moderate cardiac siderosis receiving combination therapy or deferoxamine with placebo; Trial 2 was an open label longitudinal trial assessing combination therapy in 15 TM patients with severe iron loading.ResultsIn the RCT, combination therapy with deferoxamine and deferiprone was superior to deferoxamine alone for improving RVEF (3.6 vs 0.7%, p = 0.02). The increase in RVEF was greater with lower baseline T2* 8-12 ms (4.7 vs 0.5%, p = 0.01) than with T2* 12-20 ms (2.2 vs 0.8%, p = 0.47). In patients with severe cardiac siderosis, substantial improvement in RVEF was seen with open-label combination therapy (10.5% ± 5.6%, p < 0.01).ConclusionsIn the RCT of mild to moderate cardiac iron loading, combination treatment improved RV function significantly more than deferoxamine alone. Combination treatment also improved RV function in severe cardiac siderosis. Therefore adding deferiprone to deferoxamine has beneficial effects on both RV and LV function in TM patients with cardiac siderosis.