A paradigm shift on beta-thalassaemia treatment: How will we manage this old disease with new therapies?

The Prevention of Thalassemia Revisited: A Historical and Ethical Perspective by the Thalassemia International Federation

Hemoglobinopathies are the most common monogenic disorders in humans; among them, thalassemia constitutes a serious medical and public health problem in high prevalence regions, in a geographical zone ranging from the Mediterranean Basin to China. In addition, migrations over the years have introduced thalassemia to many parts of the world. Although disease-specific programs are in place and accessible to most patients in prosperous countries, this is not the case in developing economies, where more than 75.0% of the patient population is born and lives; this concerns both prevention and treatment programs. In view of the significant improvements in public health and healthcare systems over the past few years, the Thalassemia International Federation has revisited the thalassemia prevention programs, initiatives and policies in some of its member countries, discussing their effectiveness and whether any changes in policy or public attitudes to thalassemia prevention have occurred through the recent years.

The spectrum of beta-thalassemia mutations in the 22 Arab countries: a systematic review

OBJECTIVES

To investigate the mutational spectrum in the HBB gene in Arab patients with β-thal.

METHODS

Authors searched five databases (PubMed, Science Direct, Scopus, Web of Science, and Google Scholar) from the time of inception until March 2020.

RESULTS

The authors search strategy yielded 3,229 citations, of which 48 eligible studies captured. 105 mutations were captured, of these, 99 were shared between Arabs and other ethnic groups, six mutations were unique to Arabs (c.92 + 2 T > G, c.-240 G > A, c.150delC, c.420dupT, deletion of 192 bp spanning exon 1, intron 1, and the first two bases of exon 2 of HBB gene, and deletion of 9.6 kb, including exon 1 and intron 2 of HBB gene). The most common HBB gene mutations among Arabs were c.93-21 G > A, c.118 C > T, c.92 + 1 G > A, c.92 + 6 T > C, c.92 + 5 G > C, c.315 + 1 G > A, and c.27dupG. Consanguinity is high among Arab patients with β-thal. Migration into Arab countries led to allelic heterogeneity among Arab patients with β-thal.

CONCLUSION

Our findings present a platform for further genetic epidemiological studies for Arab patients with β-thal.

Impact of activated monocyte and endothelial dysfunction on coagulopathy in Egyptian adult beta thalassemic patients

The mechanism of the well observed hypercoagulability and high incidence of Thromboembolic Events (TE) in β- thalassemia patients has not been fully elucidated. This study aimed to evaluate evaluate the endothelial dysfunction and monocyte activation among adult Egyptian β-thalassemic patients and assess their role in the hypercoagulability and development of TE. A total of 40 adults patients with bthalassemics and 20 healthy age and sex-matched controls were assessed for endothelial dysfunction using serum Von Willebrand Factor Antigen (VWFAg) and for monocytic activation using flow cytometric assessment of CD14 monocyte microparticles and CD11b activated monocytes. The VWF:Ag level was significantly higher among thalassemic patients (P<0.001) and was positively correlated to development of TE (P<0.05). There was no significance difference for CD14 between patients and controls (P>0.5) and CD11b was higher in controls (P=0.004) with no significant correlation between both and TE development (P>0.05). VWF:Ag is increased in thalassemic patients and could be used as a risk factor for thrombosis in these patients, while no identified role of activated monocytes in thrombotic tendency in such patients.

Efficacy and safety of oral hydroxyurea in transfusion-dependent β-thalassaemia: a protocol for randomised double-blind controlled clinical trial

INTRODUCTION

Despite being one of the first diseases to be genetically characterised, β-thalassaemia remains a disorder without a cure in a majority of patients. Most patients with β-thalassaemia receive only supportive treatment and therefore have a poor quality of life and shorter life spans. Hydroxyurea, which has shown to induce fetal haemoglobin synthesis in human erythroid cells, is currently recommended for the treatment of sickle cell disease. However, its clinical usefulness in transfusion-dependent β-thalassaemia is unclear. Here, we present a protocol for a randomised double-blind controlled clinical trial to evaluate the efficacy and safety of oral hydroxyurea in transfusion-dependent β-thalassaemia.

METHODS AND ANALYSIS

This single-centre randomised double-blind placebo-controlled clinical trial is conducted at the Thalassaemia Centre of Colombo North Teaching Hospital, Ragama, Sri Lanka. Adult and adolescent patients with haematologically and genetically confirmed transfusion-dependent β-thalassaemia are enrolled and randomised into the intervention or control group. The intervention group receives oral hydroxyurea 10-20 mg/kg daily for 6 months, while the control group receives a placebo which is identical in size, shape and colour to hydroxyurea without its active ingredient. Transfused blood volume, pretransfusion haemoglobin level, fetal haemoglobin percentage and adverse effects of treatment are monitored during treatment and 6 months post-treatment. Cessation or reduction of blood transfusions during the treatment period will be the primary outcome measure. The statistical analysis will be based on intention to treat.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Ethics Committee of Faculty of Medicine, University of Kelaniya (P/116/05/2018) and the trial is approved by the National Medicinal Regulatory Authority of Sri Lanka. Results of the trial will be disseminated in scientific publications in reputed journals.

TRIAL REGISTRATION NUMBER

SLCTR/2018/024; Pre-results.

Generation of an immortalised erythroid cell line from haematopoietic stem cells of a haemoglobin E/β-thalassemia patient

The β-thalassemia syndromes are the most prevalent genetic disorder globally, characterised by reduced or absent β-globin chain synthesis. HbE/β-thalassemia is a subtype of β-thalassemia with extremely high frequency in Asia. Studying molecular defects behind β-thalassemia is severely impeded by paucity of material from patients and lack of suitable cell lines. Approaches to derive erythroid cells from induced pluripotent stem cells (iPSCs) created from patients are confounded by poor levels of erythroid cell expansion, aberrant or incomplete erythroid differentiation and foetal/embryonic rather than adult globin expression. In this study we generate an immortalised erythroid cell line from peripheral blood stem cells of a HbE/β-thalassemia patient. Morphological analysis shows the cells are proerythroblasts with some early basophilic erythroblasts, with no change in morphology over time in culture. The line differentiates along the erythroid pathway to orthochromatic erythroblasts and reticulocytes. Importantly, unlike iPSCs, the line maintains the haemoglobin profile of the patient's red blood cells. This is the first human cellular model for β-thalassemia providing a sustainable source of disease cells for studying underlying disease mechanisms and for use as drug screening platform, particularly for reagents designed to increase foetal haemoglobin expression as we have additionally demonstrated with hydroxyurea.

Discovery of Novel Fetal Hemoglobin Inducers through Small Chemical Library Screening

The screening of chemical libraries based on cellular biosensors is a useful approach to identify new hits for novel therapeutic targets involved in rare genetic pathologies, such as β-thalassemia and sickle cell disease. In particular, pharmacologically mediated stimulation of human γ-globin gene expression, and increase of fetal hemoglobin (HbF) production, have been suggested as potential therapeutic strategies for these hemoglobinopathies. In this article, we screened a small chemical library, constituted of 150 compounds, using the cellular biosensor K562.GR, carrying enhanced green fluorescence protein (EGFP) and red fluorescence protein (RFP) genes under the control of the human γ-globin and β-globin gene promoters, respectively. Then the identified compounds were analyzed as HbF inducers on primary cell cultures, obtained from β-thalassemia patients, confirming their activity as HbF inducers, and suggesting these molecules as lead compounds for further chemical and biological investigations.

A multicenter cross-sectional study of the quality of life and iron chelation treatment satisfaction of patients with transfusion-dependent β-thalassemia, in routine care settings in Western Greece

PURPOSE

To evaluate health-related quality of life (HRQoL) and satisfaction with iron chelation therapy (ICT) of patients with transfusion-dependent β-thalassemia (TDT) managed under routine care conditions.

PATIENTS AND METHODS

This was an observational, multicenter, cross-sectional study conducted in three hospital-based Thalassemia Units of Western Greece. Patients confidentially completed the 36-item short-form (SF-36) and the "satisfaction with ICT" (SICT) instruments to assess HRQoL and ICT satisfaction respectively.

RESULTS

One hundred and thirty-one adult TDT patients [74 female, median (IQR) age: 41 (36-47) years] were enrolled. Eighty patients (61.1%) were receiving parenteral ICT, with or without oral chelators (Group I), whereas 51 (38.9%) were only receiving oral ICT (Group II). The median SF-36 physical component summary and mental component summary scores were 76.3 and 75.7 among Group I, and 76.9 and 74.5 among Group II patients, not differing between the two groups. In their majority, Group I (84.6%) and Group II (92.9%) patients reported preferring oral ICT. Moreover, Group I patients reported greater perceived ICT effectiveness (median SICT score: 4.3 versus 4.2; p = 0.039), whereas patients receiving deferasirox-containing ICT reported higher treatment acceptance (median SICT score: 4.0 versus 3.6, p = 0.038) and greater satisfaction with the burden of their ICT (median SICT score: 4.4 versus 3.9, p = 0.033).

CONCLUSION

TDT patients prefer to receive oral ICT and are more satisfied of the burden of deferasirox-containing ICT, even though those receiving parenteral ICT are more satisfied by the effectiveness of their treatment. No differences in HRQoL were not noted between patients receiving parenteral versus oral ICT.

Recent Progress in Gene Therapy and Other Targeted Therapeutic Approaches for Beta Thalassemia

Beta-thalassemia is a genetic disorder characterized by the impaired synthesis of the betaglobin chain of adult hemoglobin. The disorder has a complex pathophysiology that affects multiple organ systems. The main complications of beta thalassemia are ineffective erythropoiesis, chronic hemolytic anemia and hemosiderosis-induced organ dysfunction. Regular blood transfusions are the main therapy for beta thalassemia major; however, this treatment can cause cardiac and hepatic hemosiderosis - the most common cause of death in these patients. This review focuses on unique future therapeutic interventions for thalassemia that reverse splenomegaly, reduce transfusion frequency, decrease iron toxicity in organs, and correct chronic anemia. The targeted effective protocols include hemoglobin fetal inducers, ineffective erythropoiesis correctors, antioxidants, vitamins, and natural products. Resveratrol is a new herbal therapeutic approach which serves as fetal Hb inducer in beta thalassemia. Hematopoietic stem cell transplantation (HSCT) is the only curative therapy for beta thalassemia major and is preferred over iron chelation and blood transfusion for ensuring long life in these patients. Meanwhile, several molecular therapies, such as ActRIIB/IgG1 Fc recombinant protein, have emerged to address complications of beta thalassemia or the adverse effects of current drugs. Regarding gene correction strategies, a phase III trial called HGB-207 (Northstar-2; NCT02906202) is evaluating the efficacy and safety of autologous cell transplantation with LentiGlobin. Advanced gene-editing approaches aim to cut DNA at a targeted site and convert HbF to HbA during infancy, such as the suppression of BCL11A (B cell lymphoma 11A), HPFH (hereditary persistence of fetal hemoglobin) and zinc-finger nucleases. Gene therapy is progressing rapidly, with multiple clinical trials being conducted in many countries and the promise of commercial products to be available in the near future.

Ready for Repair? Gene Editing Enters the Clinic for the Treatment of Human Disease

We present an overview of clinical trials involving gene editing using clustered interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9), transcription activator-like effector nucleases (TALENs), or zinc finger nucleases (ZFNs) and discuss the underlying mechanisms. In cancer immunotherapy, gene editing is applied ex vivo in T cells, transgenic T cell receptor (tTCR)-T cells, or chimeric antigen receptor (CAR)-T cells to improve adoptive cell therapy for multiple cancer types. This involves knockouts of immune checkpoint regulators such as PD-1, components of the endogenous TCR and histocompatibility leukocyte antigen (HLA) complex to generate universal allogeneic CAR-T cells, and CD7 to prevent self-destruction in adoptive cell therapy. In cervix carcinoma caused by human papillomavirus (HPV), E6 and E7 genes are disrupted using topically applied gene editing machinery. In HIV infection, the CCR5 co-receptor is disrupted ex vivo to generate HIV-resistant T cells, CAR-T cells, or hematopoietic stem cells. In β-thalassemia and sickle cell disease, hematopoietic stem cells are engineered ex vivo to induce the production of fetal hemoglobin. AAV-mediated in vivo gene editing is applied to exploit the liver for systemic production of therapeutic proteins in hemophilia and mucopolysaccharidoses, and in the eye to restore splicing of the CEP920 gene in Leber's congenital amaurosis. Close consideration of safety aspects and education of stakeholders will be essential for a successful implementation of gene editing technology in the clinic.

Genetic Regulation of Redox Balance in β-Thalassemia Trait

β-Thalassemia (β-thal) trait is a heterogeneous group of genetic defects leading to decreased β-globin production, ineffective erythropoiesis, and oxidative stress. The aim is to evaluate the cytoprotective response, at transcriptional and systemic levels, of the variations of global redox balance in β-thal trait patients. Sixty-six subjects (40 healthy and 26 with β-thal trait) were analyzed at the Universidad Nacional de Tucumán, Tucumán, Argentina, between 2016 and 2017. The following parameters were evaluated: complete blood count, iron status, hemoglobin (Hb) electrophoresis, Hb A₂, thiobarbituric acid reactive species (TBARS), serum catalase (CAT), and superoxide dismutase (SOD) activity, FOXO3a, NRF2, SOD, PRDX2, CAT, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) gene expression. The β-thal trait group showed a decrease in Hb levels, MCV, and MCH with higher TBARS levels. The SOD activity was significantly increased by 32.0% in β-thal trait patients respect to the control group. Relative expression of NRF2 was 4.7-fold higher in β-thal trait than in the control group, while FOXO3a expression was similar in both groups. The SOD, PRDX2, and proinflammatory cytokines transcriptional expression was significantly upregulated in β-thal trait patients. This is the first study on the genetic regulation of redox balance in β-thal trait patients in which interesting modifications were observed in the transcript levels of some redox regulators that could be associated with changes in the erythrocyte proteome in this disorder. A better understanding of the pathophysiological mechanisms present in these heterozygous patients would allow adequate therapy in situations such as growth, pregnancy, or high performance sports, favoring a personalized treatment.

Red blood cell consumption in a large cohort of patients with thalassaemia: a retrospective analysis of main predictors

The phenotype/genotype relationship of patients with transfusion-dependent thalassaemia (TDT) is particularly complex and variable, thus generating different levels of severity and of annual transfusion volume (ATV). In this study, we explored the role and the contribution of several factors potentially involved in determining mean ATV in a cohort of TDT patients which have been followed since long time. We collected data on one-hundred and twenty-seven patients with transfusion-dependent β-thalassaemia followed at Rare Blood Cell Disease Unit, AORN Cardarelli Hospital. Age at first transfusion, genotype, spleen status (splenectomy or not), and mean soluble transferrin receptor (sTfR) were the parameters included in the analysis. At stepwise regression analysis which included all the parameters, only splenectomy and mean sTfR significantly predicted the mean ATV (F = 70.94, P < 0.0001, R² = 0.540). Overall, our data may suggest that in patients with TDT, the measurement of sTfR level together with the spleen status could contribute, more accurately than genotype, to provide a basal evaluation of residual erythropoietic activity and mean ATV.

A Phase 3 Trial of Luspatercept in Patients with Transfusion-Dependent β-Thalassemia

BACKGROUND

Patients with transfusion-dependent β-thalassemia need regular red-cell transfusions. Luspatercept, a recombinant fusion protein that binds to select transforming growth factor β superfamily ligands, may enhance erythroid maturation and reduce the transfusion burden (the total number of red-cell units transfused) in such patients.

METHODS

In this randomized, double-blind, phase 3 trial, we assigned, in a 2:1 ratio, adults with transfusion-dependent β-thalassemia to receive best supportive care plus luspatercept (at a dose of 1.00 to 1.25 mg per kilogram of body weight) or placebo for at least 48 weeks. The primary end point was the percentage of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 plus a reduction of at least 2 red-cell units over this 12-week interval. Other efficacy end points included reductions in the transfusion burden during any 12-week interval and results of iron studies.

RESULTS

A total of 224 patients were assigned to the luspatercept group and 112 to the placebo group. Luspatercept or placebo was administered for a median of approximately 64 weeks in both groups. The percentage of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 plus a reduction of at least 2 red-cell units over this 12-week interval was significantly greater in the luspatercept group than in the placebo group (21.4% vs. 4.5%, P<0.001). During any 12-week interval, the percentage of patients who had a reduction in transfusion burden of at least 33% was greater in the luspatercept group than in the placebo group (70.5% vs. 29.5%), as was the percentage of those who had a reduction of at least 50% (40.2% vs. 6.3%). The least-squares mean difference between the groups in serum ferritin levels at week 48 was -348 μg per liter (95% confidence interval, -517 to -179) in favor of luspatercept. Adverse events of transient bone pain, arthralgia, dizziness, hypertension, and hyperuricemia were more common with luspatercept than placebo.

CONCLUSIONS

The percentage of patients with transfusion-dependent β-thalassemia who had a reduction in transfusion burden was significantly greater in the luspatercept group than in the placebo group, and few adverse events led to the discontinuation of treatment. (Funded by Celgene and Acceleron Pharma; BELIEVE ClinicalTrials.gov number, NCT02604433; EudraCT number, 2015-003224-31.).

Minihepcidins improve ineffective erythropoiesis and splenomegaly in a new mouse model of adult β-thalassemia major

Minihepcidins are hepcidin agonists that have been previously shown to reverse iron overload and improve erythropoiesis in mice affected by non-transfusion-dependent thalassemia. Given the extreme anemia that occurred with the previous model of transfusion-dependent thalassemia, that model was inadequate for investigating whether minihepcidins can improve red blood cell quality, lifespan and ineffective erythropoiesis. To overcome this limitation, we generated a new murine model of transfusion-dependent thalassemia with severe anemia and splenomegaly, but sufficient red cells and hemoglobin production to test the effect of minihepcidins. Furthermore, this new model demonstrates cardiac iron overload for the first time. In the absence of transfusions, minihepcidins improved red blood cell morphology and lifespan as well as ineffective erythropoiesis. Administration of a minihepcidin in combination with chronic red blood cell transfusion further improved the ineffective erythropoiesis and splenomegaly and reversed cardiac iron overload. These studies indicate that drugs such as minihepcidins have therapeutic potential for patients with transfusion-dependent thalassemia.

Synergistic silencing of α-globin and induction of γ-globin by histone deacetylase inhibitor, vorinostat as a potential therapy for β-thalassaemia

β-Thalassaemia is one of the most common monogenic diseases with no effective cure in the majority of patients. Unbalanced production of α-globin in the presence of defective synthesis of β-globin is the primary mechanism for anaemia in β-thalassaemia. Clinical genetic data accumulated over three decades have clearly demonstrated that direct suppression of α-globin and induction of γ-globin are effective in reducing the globin chain imbalance in erythroid cells hence improving the clinical outcome of patients with β-thalassaemia. Here, we show that the histone deacetylase inhibitor drug, vorinostat, in addition to its beneficial effects for patients with β-thalassaemia through induction of γ-globin, has the potential to simultaneously suppress α-globin. We further show that vorinostat exhibits these synergistic beneficial effects in globin gene expression at nanomolar concentrations without perturbing erythroid expansion, viability, differentiation or the transcriptome. This new evidence will be helpful for the interpretation of existing clinical trials and future clinical studies that are directed towards finding a cure for β-thalassaemia using vorinostat.

Health related quality of life among children with transfusion dependent β-thalassaemia major and haemoglobin E β-thalassaemia in Sri Lanka: a case control study

Background

Thalassaemia is a chronic disease without an effective cure in a majority. The clinical management has improved considerably during recent years; however, minimal attempts are made to up lift the quality of life among patients, especially in developing countries. Here we aim to describe and compare and to determine factors associated with health related quality of life among patients with transfusion dependent β-thalassaemia major and haemoglobin E β-thalassemia in Sri Lanka.

Methods

A case control study was conducted in the three largest thalassaemia centres of Sri Lanka. All patients with transfusion dependent β-thalassaemia (β-thalassaemia major and haemoglobin E β-thalassaemia) aged 5–18 years were recruited as cases whilst a randomly selected group of children without chronic diseases were recruited as controls. Socio-demographic and clinical data were collected using an interviewer-administered questionnaire and health related quality of life was measured using the validated Paediatric Quality of Life Inventory Version 4.0.

Results

Two hundred and seventy one patients with transfusion dependent β-thalassaemia (male-49.1%; mean age- 10.9 ± 3.6 years) and 254 controls (male-47.2%; mean age- 10.4 ± 3.5 years) were recruited. Mean health-related quality of life scores were significantly lower in patients compared to controls (72.9 vs. 91.5, p < 0.001). Of the patients, 224 (84%) had β-thalassaemia major and 43 (16%) had haemoglobin E β-thalassaemia. Quality of life scores in psychological health (p < 0.05), emotional functioning (p < 0.05) and social functioning (p < 0.05) were significantly lower in patients with haemoglobin E β-thalassaemia compared to β-thalassaemia major. Splenectomy (p < 0.05), short stature (p < 0.05), under nutrition (p < 0.05) and longer hospital stays (p < 0.05) were significantly associated with lower quality of life scores.

Conclusions

Despite improvements in management, the quality of life among patients with β-thalassaemia still remains low. This is more pronounced in the subset of patients with haemoglobin E β-thalassaemia. Splenectomy, short stature, undernutrition and longer hospital stays were significantly associated with poor quality of life. It is timely, even in developing countries, to direct emphasis and to take appropriate steps to improve standards of living and quality of life of patients with β-thalassaemia.

Challenges of blood transfusions in β-thalassemia

Patients with β-thalassemia major (BTM) require regular blood transfusions, supported by appropriate iron chelation therapy (ICT), throughout their life. β-thalassemia is a global disease that is most highly prevalent in Southeast Asia, Africa, and Mediterranean countries. However, the global distribution of patients with β-thalassemia is changing due to population migration, and Northern European countries now have significant thalassemia populations. Globally, many patients with BTM have limited access to regular and safe blood transfusions. A lack of voluntary nonremunerated blood donors, poor awareness of thalassemia, a lack of national blood policies, and fragmented blood services contribute to a significant gap between the timely supply of, and demand for, safe blood. In many centers, there is inadequate provision of antigen testing, even for common red cell antigens such as CcEe and Kell. Policies to raise awareness and increase the use of red blood cell antigen testing and requesting of compatible blood in transfusion centers are needed to reduce alloimmunization (the development of antibodies to red blood cell antigens), which limits the effectiveness of transfusions and the potential availability of blood. Patients with BTM are also at risk of transfusion-transmitted infections unless appropriate blood screening and safety practices are in place. Hence, many patients are not transfused or are undertransfused, resulting in decreased health and quality-of-life outcomes. Hemovigilance, leukoreduction, and the ability to thoroughly investigate transfusion reactions are often lacking, especially in resource-poor countries. ICT is essential to prevent cardiac failure and other complications due to iron accumulation. Despite the availability of potentially inexpensive oral ICT, a high proportion of patients suffer complications of iron overload and die each year due to a lack of, or inadequate, ICT. Increased awareness, training, and resources are required to improve and standardize adequate blood transfusion services and ICT among the worldwide population of patients with BTM. ICT needs to be available, affordable, and correctly prescribed. Effective, safe, and affordable new treatments that reduce the blood transfusion burden in patients with β-thalassemia remain an unmet need.

EHA Research Roadmap on Hemoglobinopathies and Thalassemia: An Update

The inherited disorders of hemoglobin, which include sickle cell disease and thalassemias, are the most common and widespread distributed monogenic disorders. Due to a selective advantage in malaria regions, these hemoglobin defects are particularly frequent in Africa, Asia, or in the Mediterranean areas, where malaria was endemic until the last century. In recent decades, the globalization of migration has contributed to generate multiethnic European societies. Due to migration from countries or regions with high hemoglobinopathy frequencies such as Africa, Middle East, or Asia, large numbers of patients with these disorders are living in almost every European country today. Furthermore, the numbers are increasing because of increasing refugee flows toward Europe. Additional requirements are the development of European recommendations and guidelines for diagnosis and effective therapeutic approaches. These, together with the advancement of clinical trials using new drugs and therapeutic procedures could ameliorate the quality of life of patients affected with these diseases and increase their life expectancy. Lastly, coordinated efforts should be made to develop diagnostic pathways for thalassemias and hemoglobinopathies, in order to plan interventions, including prenatal diagnosis and cure. For these reasons, the development of new tools to reliably diagnose anemias is urgently needed and fits well with the needs of personalized medicine. In the last 15 years, hematology research has made many big leaps forward. Our general aim will be to solve several hematologic problems using these new approaches. We expect that the development of such a diagnostic tool will improve timely diagnosis throughout Europe, especially in those countries where it is difficult to gain access to "classical" diagnostic tests.

Blood transfusion therapy for β-thalassemia major and hemoglobin E β-thalassemia: Adequacy, trends, and determinants in Sri Lanka

BACKGROUND

Regular blood transfusion therapy still remains the cornerstone in the management of β-thalassemia. Although recommendations are clear for patients with β-thalassemia major, uniform transfusion guidelines are lacking for patients with hemoglobin E β-thalassemia. In this study, we aim to describe the adequacy, trends, and determinants of blood transfusion therapy in a large cohort of pediatric patients with β-thalassemia major and hemoglobin E β-thalassemia.

METHODS/PROCEDURE

This cross-sectional study was performed among all regularly transfused patents with β-thalassemia aged 2 to 18 years attending three large thalassemia centers in Sri Lanka. Data were collected using an interviewer-administered questionnaire, perusal of clinical records, and physical examination of patients by trained doctors.

RESULTS

A total of 328 patients (male 47%) were recruited; 83% had β-thalassemia major, whereas 16% had hemoglobin E β-thalassemia. Sixty-one percent of patients had low pretransfusion hemoglobin levels (< 9.0 g/dL) despite receiving high transfusion volumes (> 200 mL/kg/year) by a majority (56%). Median pretransfusion hemoglobin was significantly lower in patients with hemoglobin E β-thalassemia compared with β-thalassemia major (P < 0.001); however, there was no difference in requirement for high transfusion volumes over 200 mL/kg/year in both groups (P = 0.14). Hepatomegaly and splenomegaly were more common in hemoglobin E β-thalassemia and were associated with lower pretransfusion hemoglobin. Transfusion requirements were higher among patients with hepatitis C and in those who are underweight.

CONCLUSIONS

Over 60% of regularly transfused patients with β-thalassemia have low pretransfusion hemoglobin levels despite receiving large transfusion volumes. Patients with hemoglobin E β-thalassemia are undertransfused and specific recommendations should be developed to guide transfusions in these patients.

Role of Genomic Biomarkers in Increasing Fetal Hemoglobin Levels Upon Hydroxyurea Therapy and in β-Thalassemia Intermedia: A Validation Cohort Study

Hemoglobinopathies exhibit a remarkable phenotypic diversity in terms of disease severity, while individual genetic background plays a key role in differential response to drug treatment. In the last decade, genomic variants in genes located within, as well as outside the human β-globin cluster have been shown to be significantly associated with Hb F increase, in relation to hydroxyurea (HU) therapy in patients with these diseases. Here, we aim to determine the effect of genomic variants located in genes, such as MAP3K5, ASS1, NOS2A, TOX, PDE7B, NOS1, FLT1 and ARG2, previously shown to modulate fetal hemoglobin (Hb F) levels in patients with β type hemoglobinopathies and reflecting disease severity and response to HU therapy in an independent cohort of Greek patients with these diseases. We recruited and genotyped 45 β-thalassemia patients (β-thal), either transfusion-dependent (TDT) or non transfusion-dependent (NTDT), 42 Hb S (HBB: c.20A>T)-β-thal compound heterozygotes, who were treated with HU, as well as 53 healthy individuals, all of Hellenic origin. Our study showed that genomic variants of the MAP3K5, NOS2A and ARG2 gene are associated with HU therapy efficacy in Hb S-β-thal compound heterozygotes. We have also shown that FLT1 and ARG2 genomic variants are associated with the mild phenotype of NTDT patients. Our findings provide evidence that MAP3K5, NOS2A, ARG2 and FLT1 genomic variants could be considered as genomic biomarkers to predict HU therapy efficacy in Hb S-β-thal compound heterozygotes and also to describe disease severity in patients with β type hemoglobinopathies.

Thalassemias: An Overview

Thalassemia syndromes are among the most serious and common genetic conditions. They are indigenous in a wide but specific geographical area. However, through migration they are spreading across regions not previously affected. Thalassemias are caused by mutations in the α (HBA1/HBA2) and β globin (HBB) genes and are usually inherited in an autosomal recessive manner. The corresponding proteins form the adult hemoglobin molecule (HbA) which is a heterotetramer of two α and two β globin chains. Thalassemia-causing mutations lead to an imbalanced globin chain production and consecutively to impaired erythropoiesis. The severity of the disease is largely determined by the degree of chain imbalance. In the worst case, survival is dependent on regular blood transfusions, which in turn cause transfusional iron overload and secondary multi-organ damage due to iron toxicity. A vigorous monitoring and treatment regime is required, even for the milder syndromes. Thalassemias are a major public health issue in many populations which many health authorities fail to address. Even though comprehensive care has resulted in long-term survival and good quality of life, poor access to essential components of management results in complications which increase the cost of treatment and lead to poor outcomes. These requirements are not recognized by measures such as the Global Burden of Disease project, which ranks thalassemia very low in terms of disability-adjusted life years (DALYs), and fails to consider that it ranks highly in the one to four-year-old age group, making it an important contributor to under-5 mortality. Thalassemia does not fulfil the criteria to be accepted as a target disease for neonatal screening. Nevertheless, depending on the screening methodology, severe cases of thalassemia will be detected in most neonatal screening programs for sickle cell disease. This is very valuable because: (1) it helps to prepare the affected families for having a sick child and (2) it is an important measure of secondary prevention.

CD3+/CD19+ Depleted Matched and Mismatched Unrelated Donor Hematopoietic Stem Cell Transplant with Targeted T Cell Addback Is Associated with Excellent Outcomes in Pediatric Patients with Nonmalignant Hematologic Disorders

Unrelated donor hematopoietic stem cell transplantation (HSCT) is increasingly being used to cure nonmalignant hematologic diseases (NMHD) in patients who lack HLA matched related donors. Both graft rejection and graft-versus-host disease (GVHD) remain major barriers to safe and effective transplant for these patients requiring unrelated donors. Partial T cell depletion combined with peripheral stem cell transplantation (pTCD-PSCT) has the potential advantages of providing a high stem cell dose to facilitate rapid engraftment, maintaining cells that may facilitate engraftment, and decreasing GVHD risk compared with T cell-replete HSCT. Here, we report a single-institution, retrospective experience of unrelated donor pTCD-PSCT for pediatric patients with NMHD. From 2014 to 2017, 12 pediatric patients with transfusion-dependent NMHD underwent matched unrelated donor (MUD) or mismatched unrelated donor (MMUD) pTCD HSCT in our center using disease-specific conditioning. Donor PSCs underwent CD3+ T cell and CD19+ B cell depletion using CliniMACS, followed by a targeted addback of 1 × 105 CD3+ T cells/kg to the graft before infusion. All 12 patients demonstrated rapid trilinear engraftment. At a median follow-up of 740days (range, 279 to 1466), all patients were alive with over 92% total peripheral blood donor chimerism and without transfusion dependence or recurrence of their underlying hematologic disease. Immune reconstitution was rapid and comparable with T cell-replete HSCT. No patients developed severe acute GVHD (grades III to IV) or chronic extensive GVHD, and all patients had discontinued systemic immune suppression. Viral reactivations were common, but no patient developed symptoms of life-threatening infectious disease. Our data indicate that MUD and MMUD pTCD-PSCTs are safe and effective approaches that enable rapid engraftment and immune reconstitution, prevent severe GVHD, and expand availability of HSCT to any patients with NMHD who have closely MUDs.

Multiple Integrated Non-clinical Studies Predict the Safety of Lentivirus-Mediated Gene Therapy for β-Thalassemia

Gene therapy clinical trials require rigorous non-clinical studies in the most relevant models to assess the benefit-to-risk ratio. To support the clinical development of gene therapy for β-thalassemia, we performed in vitro and in vivo studies for prediction of safety. First we developed newly GLOBE-derived vectors that were tested for their transcriptional activity and potential interference with the expression of surrounding genes. Because these vectors did not show significant advantages, GLOBE lentiviral vector (LV) was elected for further safety characterization. To support the use of hematopoietic stem cells (HSCs) transduced by GLOBE LV for the treatment of β-thalassemia, we conducted toxicology, tumorigenicity, and biodistribution studies in compliance with the OECD Principles of Good Laboratory Practice. We demonstrated a lack of toxicity and tumorigenic potential associated with GLOBE LV-transduced cells. Vector integration site (IS) studies demonstrated that both murine and human transduced HSCs retain self-renewal capacity and generate new blood cell progeny in the absence of clonal dominance. Moreover, IS analysis showed an absence of enrichment in cancer-related genes, and the genes targeted by GLOBE LV in human HSCs are well known sites of integration, as seen in other lentiviral gene therapy trials, and have not been associated with clonal expansion. Taken together, these integrated studies provide safety data supporting the clinical application of GLOBE-mediated gene therapy for β-thalassemia.

How I manage medical complications of β-thalassemia in adults

The complex pathophysiology in β-thalassemia can translate to multiple morbidities that affect every organ system. Improved survival due to advances in management means that patients are exposed to the harmful effects of ineffective erythropoiesis, anemia, and iron overload for a longer duration, and we started seeing new or more frequent complications in adult compared with younger patients. In this article, we highlight particular aspects of managing adult patients with β-thalassemia, using our own experience in treating such patients. We cover both transfusion-dependent and nontransfusion-dependent forms of the disease and tackle specific morbidities of highest interest.