β-Thalassemias

Economic and clinical burden of managing transfusion-dependent β-thalassemia in the United States

AIMS

To describe clinical complications, treatment use, healthcare resource utilization (HCRU), and costs among patients with transfusion-dependent β-thalassemia (TDT) in the United States.

MATERIALS AND METHODS

Merative MarketScan Databases were used to identify patients with β-thalassemia between 1 March 2010, and 1 March 2019. Patients were eligible for inclusion with ≥1 inpatient claim or ≥2 outpatient claims for β-thalassemia and ≥8 red blood cell transfusions (RBCTs) during any 12-month period after and including the date of the first qualifying β-thalassemia diagnosis code. Matched controls consisted of individuals without β-thalassemia. Clinical and economic outcomes of patients were assessed during ≥12 months of follow-up, defined as the period from the index date (i.e. the first RBCT) to either the end of continuous enrollment in benefits, inpatient death, or 1 March 2020.

RESULTS

Overall, 207 patients with TDT and 1035 matched controls were identified. Most patients received iron chelation therapy (ICT) (91.3%), with a mean of 12.1 (standard deviation [SD] = 10.3) ICT claims per-patient-per-year (PPPY). Many also received RBCTs, with a mean of 14.2 (SD = 4.7) RBCTs PPPY. TDT was associated with higher annual ($137,125) and lifetime ($7.1 million) healthcare costs vs. matched controls ($4183 and $235,000, respectively). Annual costs were driven by ICT (52.1%) and RBCT use (23.6%). Patients with TDT had 7-times more total outpatient visits/encounters, 3-times more prescriptions, and 33-times higher total annual costs than matched controls.

LIMITATIONS

This analysis may underestimate the burden of TDT, as indirect healthcare costs (e.g. absenteeism, presenteeism, etc.) were not included. Results may not be generalizable to patients excluded from this analysis, including those with other types of insurance or without insurance.

CONCLUSIONS

Patients with TDT have high HCRU and direct healthcare costs. Treatments that eliminate the need for RBCTs could reduce the clinical and economic burden of managing TDT.

A rare case of schizophrenia coexistence with antiphospholipid syndrome, β-thalassemia, and monoclonal gammopathy of undetermined significance

A patient with schizophrenia who was treated with chlorpromazine developed lupus anticoagulant (LA) and antiphospholipid syndrome (APS). On protein electrophoresis, a monoclonal immunoglobulin A peak was seen in this patient, defining a condition of monoclonal gammopathy of undetermined significance. Additionally, β-thalassemia was diagnosed with the CD41-42 genotype. This condition is extremely rare, particularly in patients with schizophrenia and APS. We present a case of a patient with schizophrenia and secondary APS who had a positive LA, a significantly prolonged activated partial thromboplastin time, endogenous coagulation factor deficiency and inhibitor, no bleeding, and an unexpected finding of β-thalassemia and monoclonal IgA. Following that, a literature review on the disorders was presented.

Glucose Homeostasis and Assessment of β-Cell Function by 3-hour Oral Glucose Tolerance (OGTT) in Patients with β-Thalassemia Major with Serum Ferritin below 1,000 ng/dL: Results from a Single ICET-A Centre

Aims

The primary aim of this study was to evaluate retrospectively the glucose homeostasis and surrogate indices of insulin sensitivity and resistance, during a 3-hour oral glucose tolerance test (OGTT), in β-thalassemia major patients (β-TM) with serum ferritin (SF) below 1,000 ng/mL.

Patients and methods

The retrospective cohort study evaluated the medical records of 24 β-TM patients from 2010 to 2022. At the year of study the mean age of patients was 31.0 ± 4.1 (20-37.11) years; 13 (54.1%) were females. The most commonly used iron chelator was deferoxamine (DFO: 75%), followed by deferiprone (DFP:12.5%) and deferasirox (DFX: 12.5%). Insulin sensitivity and resistance indices were derived from OGTT. A liver iron concentration (LIC) < 3 mg/g d.w. and a global heart T2* value > 20 ms were considered as conservative cut-off values for insignificant iron overload (IOL).

Results

The mean SF levels in the whole study cohort population at the age of evaluation was 549.6 ± 232.3 ng/mL. Based on the SF levels, two groups were identified: Group A (N = 14) < 500 ng/mL and Group B (N=10) 500-1,000 ng/mL. Normal glucose tolerance (NGT) during OGTT was observed in 4 patients of Group A (28.5 %) and in 5 patients of Group B (50%) (P: 0.29). The remaining 15/24 patients (62.5%) had glucose dysregulation (GD). The mean age at starting iron chelation therapy (ICT) and the mean SF peak in Group A versus Group B were significantly higher in group A. The GD was associated with significantly attenuated IGI (first phase of insulin response) and impaired oral disposition index (oDI). Hypogonadotropic hypogonadism (HH) was the most common associated endocrine complication in both groups of patients.

Conclusions

This study showed that efficient iron chelation monotherapy in patients with β-TM and SF < 1,000 ng/ml did not entirely prevent glucose metabolism disorders, abnormalities of insulin secretion and sensitivity, and development of acquired hypogonadism.

The effectiveness of a theory-based intervention program for pregnant women with anemia: A randomized control trial

Anemia in pregnancy is a public health concern. It has been diagnosed in 27% of pregnant women in Malaysia and up to 40% of pregnant women globally. This study aimed to develop and evaluate the effectiveness of an intervention initiative based on the health belief model. The MyPinkMom program was disseminated through a mobile messaging application to pregnant women to educate them on the prevention of anemia in pregnancy. We conducted a two-arm cluster-assignment, single-blinded, randomized control trial at two government antenatal clinics in Selangor. One clinic was randomly chosen as the intervention group, and the other was chosen as the control group. Sixty pregnant women with anemia from the intervention group received the MyPinkMom intervention program in the form of six infographic video clips, and 60 pregnant women with anemia from the control group received routine counseling on anemia in pregnancy. Pregnant women who had anemia secondary to hemoglobinopathy or other chronic diseases were excluded from this study. MANOVA showed significant increases in hemoglobin, knowledge, attitude, subjective norms, and perceived behavioral control scores for adherence to iron supplements, dietary iron, and dietary vitamin C intake (p < 0.001) in the intervention group at week 6. A significant reduction also occurred in dietary tannin intake (p < 0.001) in the intervention group at week 6. The intervention group at week 6 showed a large effect on hemoglobin level increments (partial eta squared, Ƞp2 0.268), dietary iron intake (Ƞp2 0.213), knowledge of anemia in pregnancy (Ƞp2 0.622), subjective norm scores for adherence to iron supplements (Ƞp2 0.167), and reduction in dietary tannin intake (Ƞp2 0.353). Similarly, repeated measures ANOVA showed that changes in hemoglobin levels were significantly different over time (i.e., at baseline, week 6, and week 12) between the intervention and control groups (p < 0.001). Hemoglobin increased rapidly over time among participants in the intervention group but gradually in the control group. To conclude, the newly developed MyPinkMom program that was delivered through a messaging application showed effectiveness in preventing anemia during pregnancy.

Long-term safety and erythroid response with luspatercept treatment in patients with β-thalassemia

Background

β-thalassemia is a hereditary blood disorder resulting in ineffective erythropoiesis and anemia. Management of anemia with regular blood transfusions is associated with complications including iron overload. Here, we report long-term safety and efficacy results of the first clinical study of luspatercept in β-thalassemia, initiated in 2013, enrolling adults with both nontransfusion-dependent (NTD) and transfusion-dependent (TD) β-thalassemia.

Objectives

The objective was to report long-term safety data, for up to 5 years of treatment, for 64 patients with TD or NTD β-thalassemia, and long-term efficacy data for a subset of 63 patients with β-thalassemia who received high-dose luspatercept (0.6-1.25 mg/kg): 31 NTD and 32 TD patients.

Design

The study was a phase 2, noncontrolled, open-label trial comprising a dose-finding base phase and a 5-year extension phase.

Methods

Endpoints include safety; erythroid response over a continuous 12-week period [NTD: hemoglobin increase from baseline ⩾1.0 or ⩾1.5 g/dl; TD: red blood cell (RBC) transfusion burden reduction, ⩾20%, ⩾33%, or ⩾50%]; and changes in biomarkers of ineffective erythropoiesis, iron metabolism parameters, Functional Assessment of Chronic Illness Therapy - Fatigue (FACIT-F) scores, and 6-min walking distance.

Results

Median duration of luspatercept exposure for NTD and TD patients was 910 days (range, 40-1850) and 433 days (range, 21-1790), respectively. Seventeen of 31 (54.8%) NTD patients achieved a mean hemoglobin increase of ⩾1.5 g/dl and 19 of 32 (59.4%) TD patients achieved ⩾50% reduction in RBC transfusion burden, during any continuous 12-week period. Median cumulative duration of response was 1126 days (range, 127-1790) for NTD patients and 909 days (range, 87-1734) for TD patients. The most common treatment-related adverse events of any grade were bone pain, headache, and myalgia.

Conclusion

Long-term assessment of patients with β-thalassemia showed luspatercept was associated with sustained increases in hemoglobin levels in NTD patients and sustained transfusion burden reductions in TD patients.

Trial registration

(ClinicalTrials.gov Identifiers: NCT01749540 and NCT02268409).

Plain Language Summary

Long-term safety and erythroid response with luspatercept treatment in patients with β-thalassemia Background: β-thalassemia is a genetic blood disorder caused by mutations in the β-globin gene, which encodes one of the proteins that comprise hemoglobin, a key constituent of red blood cells. Patients with β-thalassemia experience anemia, the main treatment for which is blood transfusions. Long-term repeated blood transfusions lower patients' quality of life, use hospital resources, and the resulting accumulation of excess iron can cause organ failure and decrease life expectancy. The severity of the anemia experienced by patients with β-thalassemia varies; patients with transfusion-dependent β-thalassemia require regular blood transfusions, compared with those with nontransfusion-dependent β-thalassemia who require infrequent transfusions, or even none at all, to manage their symptoms. Luspatercept (Reblozyl^®) is an agent that stimulates the production of red blood cells and is used to treat anemia caused by β-thalassemia. However, the long-term effects of luspatercept treatment on patients with β-thalassemia are not known.Objective: In this study, we report the long-term safety of luspatercept in 64 adult patients with either transfusion-dependent or nontransfusion-dependent β-thalassemia, and the long-term efficacy of high-dose luspatercept (0.6-1.25 mg/kg) in a subset of 63 patients.Results: The average time period that patients were treated with luspatercept was 910 days for nontransfusion-dependent β-thalassemia and 433 days for transfusion-dependent β-thalassemia. We report that in patients with nontransfusion-dependent β-thalassemia, luspatercept treatment was associated with sustained increases, just over 3 years, in hemoglobin levels. Likewise, in transfusion-dependent β-thalassemia, luspatercept treatment was associated with a sustained reduction, 2.5 years, in the amount of blood transfusion required to manage their anemia. Long-term treatment with luspatercept was not associated with any new side effects compared with previous short-term treatment studies. The most common side effects were headache (27 patients), bone pain (20 patients), and muscle pain (14 patients) with more than 90% of these patients experiencing these side effects as mild severity.Conclusion: The results of this study show that in patients with either transfusion-dependent or nontransfusion-dependent β-thalassemia, luspatercept provides lasting reduction in anemia with mostly mild and predictable side effects.

The population incidence of thalassemia gene variants in Baise, Guangxi, P. R. China, based on random samples

OBJECTIVE

Thalassemia is a monogenic genetic disorder with a high prevalence in populations in the southern region of China. The thalassemia gene prevalence rate in the Baise population in China is high, and several rare gene variants have been detected in the population of this region during routine testing by our study group. To accurately reveal the thalassemia gene variants carried by the population in Baise, and to provide a basis for the formulation of thalassemia prevention and control policies in the region, we conducted a more comprehensive study in a randomly selected population.

RESULTS

In all, 4,800 randomized individuals were recruited for testing from Baise, and the detection of hot spot thalassemia genetic variants were performed by Gap-PCR and PCR-RDB methods, combined with the relative quantification of homologous fragments and AS-PCR to expand the detection range. The prevalence of thalassemia variants in this population was 24.19%, among which 16.69% of individuals carried α-thalassemia gene variants alone, 5.62% carried β-thalassemia gene variants alone, and 1.88% carried both variants.

CONCLUSIONS

The use of positive primary screening combined with hot spot gene variant detection alone can result in a certain degree of missed detection. In the prevention and control of thalassemia in the region, testing institutions need to pay attention to the detection of rare thalassemia gene variants such as ααα^anti4.2, ααα^anti3.7, -α^2.4, -α^21.9, β^-50, β^-90, and β^IVS-II-5, to provide more accurate genetic counseling advice to subjects.

Effective therapies for sickle cell disease: are we there yet?

Sickle cell disease (SCD) is a common genetic blood disorder associated with acute and chronic pain, progressive multiorgan damage, and early mortality. Recent advances in technologies to manipulate the human genome, a century of research and the development of techniques enabling the isolation, efficient genetic modification, and reimplantation of autologous patient hematopoietic stem cells (HSCs), mean that curing most patients with SCD could soon be a reality in wealthy countries. In parallel, ongoing research is pursuing more facile treatments, such as in-vivo-delivered genetic therapies and new drugs that can eventually be administered in low- and middle-income countries where most SCD patients reside.

A MALDI-TOF mass spectrometry-based haemoglobin chain quantification method for rapid screen of thalassaemia

BACKGROUND

Thalassaemia is one of the most common inherited monogenic diseases worldwide with a heavy global health burden. Considering its high prevalence in low and middle-income countries, a cheap, accurate and high-throughput screening test of thalassaemia prior to a more expensive confirmatory diagnostic test is urgently needed.

METHODS

In this study, we constructed a machine learning model based on MALDI-TOF mass spectrometry quantification of haemoglobin chains in blood, and for the first time, evaluated its diagnostic efficacy in 674 thalassaemia (including both asymptomatic carriers and symptomatic patients) and control samples collected in three hospitals. Parameters related to haemoglobin imbalance (α-globin, β-globin, γ-globin, α/β and α-β) were used for feature selection before classification model construction with 8 machine learning methods in cohort 1 and further model efficiency validation in cohort 2.

RESULTS

The logistic regression model with 5 haemoglobin peak features achieved good classification performance in validation cohort 2 (AUC 0.99, 95% CI 0.98-1, sensitivity 98.7%, specificity 95.5%). Furthermore, the logistic regression model with 6 haemoglobin peak features was also constructed to specifically identify β-thalassaemia (AUC 0.94, 95% CI 0.91-0.97, sensitivity 96.5%, specificity 87.8% in validation cohort 2).

CONCLUSIONS

For the first time, we constructed an inexpensive, accurate and high-throughput classification model based on MALDI-TOF mass spectrometry quantification of haemoglobin chains and demonstrated its great potential in rapid screening of thalassaemia in large populations.Key messagesThalassaemia is one of the most common inherited monogenic diseases worldwide with a heavy global health burden.We constructed a machine learning model based on MALDI-TOF mass spectrometry quantification of haemoglobin chains to screen for thalassaemia.

Increased autophagy leads to decreased apoptosis during β-thalassaemic mouse and patient erythropoiesis

β-Thalassaemia results from defects in β-globin chain production, leading to ineffective erythropoiesis and subsequently to severe anaemia and other complications. Apoptosis and autophagy are the main pathways that regulate the balance between cell survival and cell death in response to diverse cellular stresses. Herein, the death of erythroid lineage cells in the bone marrow from both β^IVS2-654-thalassaemic mice and β-thalassaemia/HbE patients was investigated. Phosphatidylserine (PS)-bearing basophilic erythroblasts and polychromatophilic erythroblasts were significantly increased in β-thalassaemia as compared to controls. However, the activation of caspase 8, caspase 9 and caspase 3 was minimal and not different from control in both murine and human thalassaemic erythroblasts. Interestingly, bone marrow erythroblasts from both β-thalassaemic mice and β-thalassaemia/HbE patients had significantly increased autophagy as shown by increased autophagosomes and increased co-localization between LC3 and LAMP-1. Inhibition of autophagy by chloroquine caused significantly increased erythroblast apoptosis. We have demonstrated increased autophagy which led to minimal apoptosis in β-thalassaemic erythroblasts. However, increased PS exposure occurring through other mechanisms in thalassaemic erythroblasts might cause rapid phagocytic removal by macrophages and consequently ineffective erythropoiesis in β-thalassaemia.

Emergent treatments for β-thalassemia and orphan drug legislations

In many countries, β-thalassemia (β-THAL) is not uncommon; however, it qualifies as a rare disease in the US and in European Union (EU), where thalassemia drugs are eligible for Orphan Drug Designation (ODD). In this paper, we evaluate all 28 ODDs for β-THAL granted since 2001 in the US and the EU: of these, ten have since been discontinued, twelve are pending, and six have become licensed drugs available for clinical use. The prime mover for these advances has been the increasing depth of understanding of the pathophysiology of β-THAL; at the same time, and even though only one-fifth of β-THAL ODDs have become licensed drugs, the ODD legislation has clearly contributed substantially to the development of improved treatments for β-THAL.

Influences of rare copy-number variation on human complex traits

The human genome contains hundreds of thousands of regions harboring copy-number variants (CNV). However, the phenotypic effects of most such polymorphisms are unknown because only larger CNVs have been ascertainable from SNP-array data generated by large biobanks. We developed a computational approach leveraging haplotype sharing in biobank cohorts to more sensitively detect CNVs. Applied to UK Biobank, this approach accounted for approximately half of all rare gene inactivation events produced by genomic structural variation. This CNV call set enabled a detailed analysis of associations between CNVs and 56 quantitative traits, identifying 269 independent associations (p < 5 × 10-8) likely to be causally driven by CNVs. Putative target genes were identifiable for nearly half of the loci, enabling insights into dosage sensitivity of these genes and uncovering several gene-trait relationships. These results demonstrate the ability of haplotype-informed analysis to provide insights into the genetic basis of human complex traits.

Prevalence and molecular characterization of alpha and beta-Thalassemia mutations among Hakka people in southern China

Our aim was to investigate molecular features of thalassemia for proper clinical consultation and prevention in Heyuan. In our research, a total of 25,437 positive screening subjects were further subjected to a genetic analysis of α-thalassemia (α-thal) and β-thalassemia (β-thal). The deletion of α-thal mutation was tested by Gap-PCR, while the non-deletion of α-thal and β-thal mutation were identified by the PCR-reverse dot blot (PCR-RDB) technique. Nested PCR detected Hkαα/-- SEA and Hkαα/αα. Among the 25,437 positive screening subjects, 44.09% (11216/25437) subjects were bearers of thalassemia variations, and 30.85% (7847/25437) subjects showed α-thal changes alone. Among the 23 genotypes with α-thal mutation alone, the three common genotypes were --SEA/αα(68.34%), -α3.7/αα(16.44%), and -α4.2/αα(6.38%). Of the 11.50% (2924/25437) subjects and 29 genotypes with β-thal mutation alone, the three common genotypes were βCD41-42/βN(36.22%), βIVS-II-654/βN(30.88%), and β-28/βN(13.47%). Additionally, of the 1.75% (445/25437) subjects and 55 genotypes showed both α- and β-thal mutations. We also identified 269 cases of Hb H and six patients of Hkαα. Furthermore, the common genotypes of α-thal and β-thal mutations were consistent with allele frequencies of mutations. Our study establishes molecular features of thalassemia among Hakka people in Heyuan. It will be useful for developing strategies to prevent thalassemia.

Non-Transfusion-Dependent Thalassemia: A Panoramic Review

Non-transfusion-dependent thalassemia (NTDT) has been considered less severe than its transfusion-dependent variants. The most common forms of NTDT include β-thalassemia intermedia, hemoglobin E/beta thalassemia, and hemoglobin H disease. Patients with NTDT develop several clinical complications, despite their regular transfusion independence. Ineffective erythropoiesis, iron overload, and hypercoagulability are pathophysiological factors that lead to morbidities in these patients. Therefore, an early and accurate diagnosis of NTDT is essential to ascertaining early interventions. Currently, several conventional management options are available, with guidelines suggested by the Thalassemia International Federation, and novel therapies are being developed in light of the advancement of the understanding of this disease. This review aimed to increase clinicians’ awareness of NTDT, from its basic medical definition and genetics to its pathophysiology. Specific complications to NTDT were reviewed, along with the risk factors for its development. The indications of different therapeutic options were outlined, and recent advancements were reviewed.

Acute Promyelocytic Leukemia in a Woman with Thalassemia Intermedia: Case Report and Review of Literature on Hematological Malignancies in β-Thalassemia Patients

Patients affected by transfusion-dependent β-thalassemia are prone to developing several clinical complications, mostly related to the iron overload. We report the case of a patient affected by transfusion-dependent β-thalassemia (TDT) developing acute promyelocytic leukemia (APL). In our case, the therapeutic management was significantly complicated not only by myocardial dysfunction, but also by the occurrence of the differentiation syndrome following all-trans retinoic acid (ATRA) administration. We carried out a careful revision of the current literature on the occurrence of hematological malignancies in β-thalassemia patients to investigate the major complications so far described. APL occurrence in β-thalassemia patients has been very rarely reported, and our experience suggests that TDT patients suffering pre-existing comorbidities may develop a potentially fatal complication during ATRA therapy.

Right in time: Mitapivat for the treatment of anemia in α- and β-thalassemia

Kuo and colleagues¹ evaluated the safety and efficacy of mitapivat, an oral pyruvate kinase activator, in adults with non-transfusion-dependent α-thalassemia or β-thalassemia. The high rate of hemoglobin response and good tolerability encourages further development in thalassemia.

MALDI-TOF-MS for Rapid Screening and Typing of β-Globin Variant and β-Thalassemia through Direct Measurements of Intact Globin Chains

BACKGROUND

Traditional phenotype-based screening for β-globin variant and β-thalassemia using hematological parameters is time-consuming with low-resolution detection. Development of a MALDI-TOF-MS assay using alternative markers is needed.

METHODS

We constructed a MALDI-TOF-MS-based approach for identifying various β-globin disorders and classifying thalassemia major (TM) and thalassemia intermedia (TI) patients using 901 training samples with known HBB/HBA genotypes. We then validated the accuracy of population screening and clinical classification in 2 separate cohorts consisting of 16 172 participants and 201 β-thalassemia patients. Traditional methods were used as controls. Genetic tests were considered the gold standard for testing positive specimens.

RESULTS

We established a prediction model for identifying different forms of β-globin disorders in a single MALDI-TOF-MS test based on δ- to β-globin, γ- to α-globin, γ- to β-globin ratios, and/or the abnormal globin-chain patterns. Our validation study yielded comparable results of clinical specificity (99.89% vs 99.71%), and accuracy (99.78% vs 99.16%) between the new assay and traditional methods but higher clinical sensitivity for the new method (97.52% vs 88.01%). The new assay identified 22 additional abnormal hemoglobins in 69 individuals including 9 novel ones, and accurately screened for 9 carriers of deletional hereditary persistence of fetal hemoglobin or δβ-thalassemia. TM and TI were well classified in 178 samples out of 201 β-thalassemia patients.

CONCLUSIONS

MALDI-TOF-MS is a highly accurate, predictive tool that could be suitable for large-scale screening and clinical classification of β-globin disorders.

Activation of γ-globin expression by hypoxia-inducible factor 1α

Around birth, globin expression in human red blood cells (RBCs) shifts from γ-globin to β-globin, which results in fetal haemoglobin (HbF, α2γ2) being gradually replaced by adult haemoglobin (HbA, α2β2)1. This process has motivated the development of innovative approaches to treat sickle cell disease and β-thalassaemia by increasing HbF levels in postnatal RBCs2. Here we provide therapeutically relevant insights into globin gene switching obtained through a CRISPR-Cas9 screen for ubiquitin-proteasome components that regulate HbF expression. In RBC precursors, depletion of the von Hippel-Lindau (VHL) E3 ubiquitin ligase stabilized its ubiquitination target, hypoxia-inducible factor 1α (HIF1α)3,4, to induce γ-globin gene transcription. Mechanistically, HIF1α-HIF1β heterodimers bound cognate DNA elements in BGLT3, a long noncoding RNA gene located 2.7 kb downstream of the tandem γ-globin genes HBG1 and HBG2. This was followed by the recruitment of transcriptional activators, chromatin opening and increased long-range interactions between the γ-globin genes and their upstream enhancer. Similar induction of HbF occurred with hypoxia or with inhibition of prolyl hydroxylase domain enzymes that target HIF1α for ubiquitination by the VHL E3 ubiquitin ligase. Our findings link globin gene regulation with canonical hypoxia adaptation, provide a mechanism for HbF induction during stress erythropoiesis and suggest a new therapeutic approach for β-haemoglobinopathies.

Luspatercept for the treatment of anaemia in non-transfusion-dependent β-thalassaemia (BEYOND): a phase 2, randomised, double-blind, multicentre, placebo-controlled trial

BACKGROUND

In patients with non-transfusion-dependent β-thalassaemia, haemoglobin concentrations lower than 10 g/dL are associated with a higher risk of morbidity, mortality, and impaired quality of life. No drugs are specifically approved for anaemia management in patients with non-transfusion-dependent β-thalassaemia, other than transfusion therapy administered infrequently in accordance with patients' needs. We assessed the efficacy and safety of luspatercept versus placebo in patients with non-transfusion-dependent β-thalassaemia.

METHODS

We did a phase 2, randomised, double-blind, multicentre, placebo-controlled trial in 12 centres in six countries (Thailand [n=1], Lebanon [n=1], Greece [n=2], Italy [n=5], the UK [n=1], and the USA [n=2]). Eligible patients were aged 18 years or older, had confirmed diagnosis of β-thalassaemia or haemoglobin E/β-thalassaemia (concomitant α-globin deletion, mutation, or duplication were allowed), and a baseline haemoglobin concentration of 10·0 g/dL or lower. All patients were non-transfusion-dependent. Patients were randomly assigned (2:1) to luspatercept or placebo using an interactive response technology system and stratified by baseline haemoglobin concentration (≥8·5 g/dL vs <8·5 g/dL) and baseline Non-Transfusion-Dependent β-thalassaemia-Patient-Reported Outcome Tiredness/Weakness domain score (≥3 vs <3). All patients, study site staff, and sponsor representatives (who reviewed the data), except for designated individuals, were masked to drug assignment until the time the study was unblinded. Luspatercept or placebo was given once subcutaneously every 3 weeks for 48 weeks in the double-blind treatment period. Luspatercept was started at 1·0 mg/kg with titration up to 1·25 mg/kg, or reduction in the event of toxicity or excessive haemoglobin concentration increase. The primary endpoint was achievement of an increase from baseline of 1·0 g/dL or higher in mean haemoglobin concentration over a continuous 12-week interval during weeks 13-24, in the absence of transfusions. The primary efficacy and safety analyses were done in the intention-to-treat population. This trial is registered at ClinicalTrials.gov, NCT03342404, and is ongoing.

FINDINGS

Between Feb 5, 2018, and Oct 14, 2019, 160 patients were screened for eligiblity, of whom 145 were randomly assigned to luspatercept (n=96) or placebo (n=49). 82 (57%) patients were female and 63 (43%) were male. 44 (30%) patients were Asian, 87 (60%) were White, and 14 (10%) identified as another race. The study met its primary endpoint: 74 (77%) of 96 patients in the luspatercept group and none in the placebo group had an increase of at least 1·0 g/dL in haemoglobin concentration (common risk difference 77·1 [95% CI 68·7-85·5]; p<0·0001). The proportion of patients with serious adverse events was lower in the luspatercept group than in the placebo group (11 [12%] vs 12 [25%]). Treatment-emergent adverse events most commonly reported with luspatercept were bone pain (35 [37%]), headache (29 [30%]), and arthralgia (28 [29%]). No thromboembolic events or deaths were reported during the study.

INTERPRETATION

Luspatercept represents a potential treatment for adult patients with non-transfusion-dependent β-thalassaemia, for whom effective approved treatment options are scarce.

FUNDING

Celgene and Acceleron Pharma.

Transferrin receptor 2 (Tfr2) genetic deletion makes transfusion-independent a murine model of transfusion-dependent β-thalassemia

β-thalassemia is a genetic disorder caused by mutations in the β-globin gene, and characterized by anemia, ineffective erythropoiesis and iron overload. Patients affected by the most severe transfusion-dependent form of the disease (TDT) require lifelong blood transfusions and iron chelation therapy, a symptomatic treatment associated with several complications. Other therapeutic opportunities are available, but none is fully effective and/or applicable to all patients, calling for the identification of novel strategies. Transferrin receptor 2 (TFR2) balances red blood cells production according to iron availability, being an activator of the iron-regulatory hormone hepcidin in the liver and a modulator of erythropoietin signaling in erythroid cells. Selective Tfr2 deletion in the BM improves anemia and iron-overload in non-TDT mice, both as a monotherapy and, even more strikingly, in combination with iron-restricting approaches. However, whether Tfr2 targeting might represent a therapeutic option for TDT has never been investigated so far. Here, we prove that BM Tfr2 deletion improves anemia, erythrocytes morphology and ineffective erythropoiesis in the Hbb^th1/th2 murine model of TDT. This effect is associated with a decrease in the expression of α-globin, which partially corrects the unbalance with β-globin chains and limits the precipitation of misfolded hemoglobin, and with a decrease in the activation of unfolded protein response. Remarkably, BM Tfr2 deletion is also sufficient to avoid long-term blood transfusions required for survival of Hbb^th1/th2 animals, preventing mortality due to chronic anemia and reducing transfusion-associated complications, such as progressive iron-loading. Altogether, TFR2 targeting might represent a promising therapeutic option also for TDT.

The Roles of Mitophagy and Autophagy in Ineffective Erythropoiesis in β-Thalassemia

β-Thalassemia is one of the most common genetically inherited disorders worldwide, and it is characterized by defective β-globin chain synthesis leading to reduced or absent β-globin chains. The excess α-globin chains are the key factor leading to the death of differentiating erythroblasts in a process termed ineffective erythropoiesis, leading to anemia and associated complications in patients. The mechanism of ineffective erythropoiesis in β-thalassemia is complex and not fully understood. Autophagy is primarily known as a cell recycling mechanism in which old or dysfunctional proteins and organelles are digested to allow recycling of constituent elements. In late stage, erythropoiesis autophagy is involved in the removal of mitochondria as part of terminal differentiation. Several studies have shown that autophagy is increased in earlier erythropoiesis in β-thalassemia erythroblasts, as compared to normal erythroblasts. This review summarizes what is known about the role of autophagy in β-thalassemia erythropoiesis and shows that modulation of autophagy and its interplay with apoptosis may provide a new therapeutic route in the treatment of β-thalassemia. Literature was searched and relevant articles were collected from databases, including PubMed, Scopus, Prospero, Clinicaltrials.gov, Google Scholar, and the Google search engine. Search terms included: β-thalassemia, ineffective erythropoiesis, autophagy, novel treatment, and drugs during the initial search. Relevant titles and abstracts were screened to choose relevant articles. Further, selected full-text articles were retrieved, and then, relevant cross-references were scanned to collect further information for the present review.

Cardiopulmonary testing in adult patients with β-thalassemia major in comparison to healthy subjects

β-Thalassemia patients often have a reduced capacity of exercise and abnormal respiratory function parameters, but the reasons are unclear. In order to identify the causes of the exercise limitation, we performed a cardiopulmonary exercise testing (CPET) in a group of 54 adult β-thalassemia major (TM) patients without pulmonary arterial hypertension and in a group of healthy control subjects. All subjects underwent cardiac echocardiography and carried out pulmonary function tests. TM patients also filled an IPAQ questionnaire on usual physical activity (PA).Overall, TM patients have a diminished exercise performance in comparison to control subjects. In fact, peak oxygen uptake (V'O₂ peak), expressing maximum exercise capacity, was decreased in 81.5% of the patients; similarly, anaerobic threshold (V'O₂@AT) and O₂ pulse also resulted lowered. In multivariable regression models adjusted for gender, age, BMI, and mean haemoglobin, V'O₂ peak and O₂ pulse were positively associated with cardiac iron overload (T2*). No ventilatory limitation to exercise was observed. The most important causes of exercise limitation in these patients were muscular deconditioning and reduced cardiac inotropism due to iron deposition. Only 15/54 (27.8%) TM patients used to perform vigorous physical activity. These results suggest that a program of regular physical activity may be useful to increase the tolerance to effort and therefore to improve the quality of life in these patients.

[Diagnostics and treatment of alpha- and beta-thalassemias]

Thalassemias are a heterogeneous group of genetic diseases based on a quantitative disorder of globin chain synthesis. They are among the most frequent monogenic hereditary diseases worldwide. Migration during recent years led to a profoundly increasing number of patients in countries where the indigenous population has not been affected. The complex treatment of the patients represents a medical and socioeconomic challenge with the need for structured interdisciplinary clinical care and close collaboration among healthcare providers, regulatory authorities, and health care insurance companies. The following article provides an overview of the causes, pathogenesis, clinical presentation, and treatment of alpha- and beta-thalassemias.

Luspatercept, a two-edged sword in beta-thalassemia-associated paravertebral extramedullary hematopoietic masses (EHMs)

Paravertebral extramedullary hematopoietic masses (EHMs) account for up to 15% of extramedullary pseudotumors in beta-thalassemia (BT) and are most likely related to compensatory hematopoiesis. In most cases, pseudotumors are incidentally detected, as the majority of patients are asymptomatic. Since June 2020, luspatercept is approved for the treatment of patients with BT who require regular red blood cell transfusions. Data addressing the safety and efficacy of luspatercept in patients with BT-associated EHMs are pending. To date (May 2022), paravertebral EHMs were observed in two asymptomatic patients out of currently 43 adult patients with BT registered at the Adult Hemoglobinopathy Outpatient Unit of the University Hospital Essen, Germany. In one of them, a paravertebral EHM was diagnosed for more than 10 years prior to referral. Throughout observation time, treatment with luspatercept was associated with a clinically significant reduction in transfusion burden while allowing to maintain a baseline hemoglobin concentration of ≥10 g/dl aiming to suppress endogenous (ineffective) erythropoiesis associated with BT. Considering the rarity of paravertebral EHMs in BT, luspatercept might potentially represent a novel therapeutic option for these often-serious disease-associated complications. However, appropriate follow-up investigations are recommended to detect (early) treatment failures secondary to an undesired luspatercept-associated erythroid expansion.

Does Hepcidin Tuning Have a Role among Emerging Treatments for Thalassemia?

The treatments available for thalassemia are rapidly evolving, with major advances made in gene therapy and the modulation of erythropoiesis. The latter includes the therapeutic potential of hepcidin tuning. In thalassemia, hepcidin is significantly depressed, and any rise in hepcidin function has a positive effect on both iron metabolism and erythropoiesis. Synthetic hepcidin and hepcidin mimetics have been developed to the stage of clinical trials. However, they have failed to produce an acceptable efficacy/safety profile. It seems difficult to avoid iron over-restricted erythropoiesis when directly using hepcidin as a drug. Indirect approaches, each one with their advantages and disadvantages, are many and in full development. The ideal approach is to target erythroferrone, the main inhibitor of hepcidin expression, the plasma concentrations of which are greatly increased in iron-loading anemias. Potential means of improving hepcidin function in thalassemia also include acting on TMPRSS6, TfR1, TfR2 or ferroportin, the target of hepcidin. Only having a better understanding of the crosslinks between iron metabolism and erythropoiesis will elucidate the best single option. In the meantime, many potential combinations are currently being explored in preclinical studies. Any long-term clinical study on this approach should include the wide monitoring of functions, as the effects of hepcidin and its modulators are not limited to iron metabolism and erythropoiesis. It is likely that some of the aspects of hepcidin tuning described briefly in this review will play a role in the future treatment of thalassemia.

A Rational Approach to Drug Repositioning in β-thalassemia: Induction of Fetal Hemoglobin by Established Drugs

Drug repositioning and the relevance of orphan drug designation for β-thalassemia is reviewed. Drug repositioning and similar terms ('drug repurposing', 'drug reprofiling', 'drug redirecting', 'drug rescue', 'drug re-tasking' and/or 'drug rediscovery') have gained great attention, especially in the field or rare diseases (RDs), and represent relevant novel drug development strategies to be considered together with the "off-label" use of pharmaceutical products under clinical trial regimen. The most significant advantage of drug repositioning over traditional drug development is that the repositioned drug has already passed a significant number of short- and long-term toxicity tests, as well as it has already undergone pharmacokinetic and pharmacodynamic (PK/PD) studies. The established safety of repositioned drugs is known to significantly reduce the probability of project failure. Furthermore, development of repurposed drugs can shorten much of the time needed to bring a drug to market. Finally, patent filing of repurposed drugs is expected to catch the attention of pharmaceutical industries interested in the development of therapeutic protocols for RDs. Repurposed molecules that could be proposed as potential drugs for β-thalassemia, will be reported, with some of the most solid examples, including sirolimus (rapamycin) that recently has been tested in a pilot clinical trial.

A Rational Approach to Drug Repositioning in β-thalassemia: Induction of Fetal Hemoglobin by Established Drugs

Drug repositioning and the relevance of orphan drug designation for β-thalassemia is reviewed. Drug repositioning and similar terms ('drug repurposing', 'drug reprofiling', 'drug redirecting', 'drug rescue', 'drug re-tasking' and/or 'drug rediscovery') have gained great attention, especially in the field or rare diseases (RDs), and represent relevant novel drug development strategies to be considered together with the "off-label" use of pharmaceutical products under clinical trial regimen. The most significant advantage of drug repositioning over traditional drug development is that the repositioned drug has already passed a significant number of short- and long-term toxicity tests, as well as it has already undergone pharmacokinetic and pharmacodynamic (PK/PD) studies. The established safety of repositioned drugs is known to significantly reduce the probability of project failure. Furthermore, development of repurposed drugs can shorten much of the time needed to bring a drug to market. Finally, patent filing of repurposed drugs is expected to catch the attention of pharmaceutical industries interested in the development of therapeutic protocols for RDs. Repurposed molecules that could be proposed as potential drugs for β-thalassemia, will be reported, with some of the most solid examples, including sirolimus (rapamycin) that recently has been tested in a pilot clinical trial.

A Rational Approach to Drug Repositioning in β-thalassemia: Induction of Fetal Hemoglobin by Established Drugs

Drug repositioning and the relevance of orphan drug designation for β-thalassemia is reviewed. Drug repositioning and similar terms ('drug repurposing', 'drug reprofiling', 'drug redirecting', 'drug rescue', 'drug re-tasking' and/or 'drug rediscovery') have gained great attention, especially in the field or rare diseases (RDs), and represent relevant novel drug development strategies to be considered together with the "off-label" use of pharmaceutical products under clinical trial regimen. The most significant advantage of drug repositioning over traditional drug development is that the repositioned drug has already passed a significant number of short- and long-term toxicity tests, as well as it has already undergone pharmacokinetic and pharmacodynamic (PK/PD) studies. The established safety of repositioned drugs is known to significantly reduce the probability of project failure. Furthermore, development of repurposed drugs can shorten much of the time needed to bring a drug to market. Finally, patent filing of repurposed drugs is expected to catch the attention of pharmaceutical industries interested in the development of therapeutic protocols for RDs. Repurposed molecules that could be proposed as potential drugs for β-thalassemia, will be reported, with some of the most solid examples, including sirolimus (rapamycin) that recently has been tested in a pilot clinical trial.

Development of a double shmiR lentivirus effectively targeting both BCL11A and ZNF410 for enhanced induction of fetal hemoglobin to treat β-hemoglobinopathies

A promising treatment for β-hemoglobinopathies is the de-repression of γ-globin expression leading to increased fetal hemoglobin (HbF) by targeting BCL11A. Here, we aim to improve a lentivirus vector (LV) containing a single BCL11A shmiR (SS) to further increase γ-globin induction. We engineered a novel LV to express two shmiRs simultaneously targeting BCL11A and the γ-globin repressor ZNF410. Erythroid cells derived from human HSCs transduced with the double shmiR (DS) showed up to a 70% reduction of both BCL11A and ZNF410 proteins. There was a consistent and significant additional 10% increase in HbF compared to targeting BCL11A alone in erythroid cells. Erythrocytes differentiated from SCD HSCs transduced with the DS demonstrated significantly reduced in vitro sickling phenotype compared to the SS. Erythrocytes differentiated from transduced HSCs from β-thalassemia major patients demonstrated improved globin chain balance by increased γ-globin with reduced microcytosis. Reconstitution of DS-transduced cells from Berkeley SCD mice was associated with a statistically larger reduction in peripheral blood hemolysis markers compared with the SS vector. Overall, these results indicate that the DS LV targeting BCL11A and ZNF410 can enhance HbF induction for treating β-hemoglobinopathies and could be used as a model to simultaneously and efficiently target multiple gene products.

2021 Thalassaemia International Federation Guidelines for the Management of Transfusion-dependent Thalassemia

Beta-thalassemia and particularly its transfusion-dependent form (TDT) is a demanding clinical condition, requiring life-long care and follow-up, ideally in specialized centers and by multidisciplinary teams of experts. Despite the significant progress in TDT diagnosis and treatment over the past decades that has dramatically improved patients’ prognosis, its management remains challenging. On one hand, diagnostic and therapeutic advances are not equally applied to all patients across the world, particularly in several high-prevalence eastern regions. On the other, healthcare systems in low-prevalence western countries that have recently received large numbers of migrant thalassemia patients, were not ready to address patients’ special needs. Thalassaemia International Federation (TIF), a global patient-driven umbrella federation with 232 member-associations in 62 countries, strives for equal access to quality care for all patients suffering from thalassemia or other hemoglobinopathies in every part of the world by promoting education, research, awareness, and advocacy. One of TIF’s main actions is the development and dissemination of clinical practice guidelines for the management of these patients. In 2021, the fourth edition of TIF’s guidelines for the management of TDT was published. The full text provides detailed information on the management of TDT patients and the clinical presentation, pathophysiology, diagnostic approach, and treatment of disease complications or other clinical entities that may occur in these patients, while also covering relevant psychosocial and organizational issues. The present document is a summary of the 2021 TIF guidelines for TDT that focuses mainly on clinical practice issues and recommendations.

A spectrum of recessiveness among Mendelian disease variants in UK Biobank

Recent work has found increasing evidence of mitigated, incompletely penetrant phenotypes in heterozygous carriers of recessive Mendelian disease variants. We leveraged whole-exome imputation within the full UK Biobank cohort (n ∼ 500K) to extend such analyses to 3,475 rare variants curated from ClinVar and OMIM. Testing these variants for association with 58 quantitative traits yielded 102 significant associations involving variants previously implicated in 34 different diseases. Notable examples included a POR missense variant implicated in Antley-Bixler syndrome that associated with a 1.76 (SE 0.27) cm increase in height and an ABCA3 missense variant implicated in interstitial lung disease that associated with reduced FEV1/FVC ratio. Association analyses with 1,134 disease traits yielded five additional variant-disease associations. We also observed contrasting levels of recessiveness between two more-common, classical Mendelian diseases. Carriers of cystic fibrosis variants exhibited increased risk of several mitigated disease phenotypes, whereas carriers of spinal muscular atrophy alleles showed no evidence of altered phenotypes. Incomplete penetrance of cystic fibrosis carrier phenotypes did not appear to be mediated by common allelic variation on the functional haplotype. Our results show that many disease-associated recessive variants can produce mitigated phenotypes in heterozygous carriers and motivate further work exploring penetrance mechanisms.

Adherence to Iron Chelation Therapy among Adults with Thalassemia: A Systematic Review

Iron chelation therapy (ICT) is essential to prevent complications of iron overload in patients with transfusion-dependent thalassemia. However, the role that adherence to ICT plays in health-related outcomes is less well known. Our objectives were to identify adherence rates of ICT, and to assess methods of measurement, predictors of adherence, and adherence-related health outcomes in the literature published between 1980 and 2020. Of 543 articles, 43 met the inclusion criteria. Studies measured ICT adherence, predictors, and/or outcomes associated with adherence. Most studies were across multiple countries in Europe and North America (n = 8/43, 18.6%), recruited in clinics (n = 39/43, 90.7%), and focused on β-thalassemia (β-thal) (n = 25/43, 58.1%). Common methods of assessing ICT adherence included patient self-report (n = 24/43, 55.8%), pill count (n = 9/43, 20.9%), prescription refill history (n = 3/43, 7.0%), provider scoring (n = 3/43, 7.0%), and combinations of methods (n = 4/43, 9.3%). Studies reported adherence either in 'categories' with different levels of adherence (n = 24) or 'quantitatively' as a percentage of doses of medication taken out of those prescribed (n = 17). Adherence levels varied (median 91.7%, range 42.0-99.97%). Studies varied in sample size and methods of adherence assessment and reporting, which prohibited meta-analysis. Due to a lack of consensus on how adherence is defined, it is difficult to compare ICT adherence reporting. Further research is needed to establish guidelines for assessing adherence and identifying suboptimal adherence. Behavioral digital interventions have the potential to optimize ICT adherence and health outcomes.

Thalassaemia

Thalassaemia is a diverse group of genetic disorders with a worldwide distribution affecting globin chain synthesis. The pathogenesis of thalassaemia lies in the unbalanced globin chain production, leading to ineffective erythropoiesis, increased haemolysis, and deranged iron homoeostasis. The clinical phenotype shows heterogeneity, ranging from close to normal without complications to severe requiring lifelong transfusion support. Conservative treatment with transfusion and iron chelation has transformed the natural history of thalassaemia major into a chronic disease with a prolonged life expectancy, albeit with co-morbidities and substantial disease burden. Curative therapy with allogeneic haematopoietic stem cell transplantation is advocated for suitable patients. The understanding of the pathogenesis of the disease is guiding therapeutic advances. Novel agents have shown efficacy in improving anaemia and transfusion burden, and initial results from gene therapy approaches are promising. Despite scientific developments, worldwide inequality in the access of health resources is a major concern, because most patients live in underserved areas.

Pharmacological Induction of Fetal Hemoglobin in β-Thalassemia and Sickle Cell Disease: An Updated Perspective

A significant amount of attention has recently been devoted to the mechanisms involved in hemoglobin (Hb) switching, as it has previously been established that the induction of fetal hemoglobin (HbF) production in significant amounts can reduce the severity of the clinical course in diseases such as β-thalassemia and sickle cell disease (SCD). While the induction of HbF using lentiviral and genome-editing strategies has been made possible, they present limitations. Meanwhile, progress in the use of pharmacologic agents for HbF induction and the identification of novel HbF-inducing strategies has been made possible as a result of a better understanding of γ-globin regulation. In this review, we will provide an update on all current pharmacological inducer agents of HbF in β-thalassemia and SCD in addition to the ongoing research into other novel, and potentially therapeutic, HbF-inducing agents.

Redox Balance in β-Thalassemia and Sickle Cell Disease: A Love and Hate Relationship

β-thalassemia and sickle cell disease (SCD) are inherited hemoglobinopathies that result in both quantitative and qualitative variations in the β-globin chain. These in turn lead to instability in the generated hemoglobin (Hb) or to a globin chain imbalance that affects the oxidative environment both intracellularly and extracellularly. While oxidative stress is not among the primary etiologies of β-thalassemia and SCD, it plays a significant role in the pathogenesis of these diseases. Different mechanisms exist behind the development of oxidative stress; the result of which is cytotoxicity, causing the oxidation of cellular components that can eventually lead to cell death and organ damage. In this review, we summarize the mechanisms of oxidative stress development in β-thalassemia and SCD and describe the current and potential antioxidant therapeutic strategies. Finally, we discuss the role of targeted therapy in achieving an optimal redox balance.

Targeting the Hematopoietic Stem Cell Niche in β-Thalassemia and Sickle Cell Disease

In the last decade, research on pathophysiology and therapeutic solutions for β-thalassemia (BThal) and sickle cell disease (SCD) has been mostly focused on the primary erythroid defect, thus neglecting the study of hematopoietic stem cells (HSCs) and bone marrow (BM) microenvironment. The quality and engraftment of HSCs depend on the BM microenvironment, influencing the outcome of HSC transplantation (HSCT) both in allogeneic and in autologous gene therapy settings. In BThal and SCD, the consequences of severe anemia alter erythropoiesis and cause chronic stress in different organs, including the BM. Here, we discuss the recent findings that highlighted multiple alterations of the BM niche in BThal and SCD. We point out the importance of improving our understanding of HSC biology, the status of the BM niche, and their functional crosstalk in these disorders towards the novel concept of combined therapies by not only targeting the genetic defect, but also key players of the HSC–niche interaction in order to improve the clinical outcomes of transplantation.

Does size matter? Two new deletions in the HBB gene cause β0-thalassemia

Most β-thalassemias are caused by mutations involving one or a limited number of nucleotides within the gene or its adjacent regions. They can be substitutions or deletions; in these cases, the loss ranges from a single nucleotide to even the entire HBB gene, so we wonder if the phenotype is due to the size of the deletion or the location of the mutation. To clarify this, we present two new deletions in the β-globin gene that cause β⁰-thalassemia. The hematological parameters were determined with an automated cell counter; the Hb A2 and Hb F levels were measured by performance liquid chromatography. Hemoglobins were analyzed by capillary zone electrophoresis (Sebia Capillarys Flex system) and ion-exchange HPLC (BioRad Variant II β-thalassemia Short Program). Molecular characterization was performed by automatic Sanger sequencing. The screening of common α-thalassemia point mutations and deletions in the world (21 in total) were carried out using multiplex PCR followed by reverse-hybridization with a commercial Alpha-Globin StripAssay kit. We have characterized two new mutations-(1) 1-bp deletion [CD61/62(-G)] [HBB:c.186_187delG], (2) 105-bp deletion [IVS-2-nt767-CD111] [HBB:c.316-84_333del]-and we have described, for first time in Spain, the 25-bp deletion [β nts 252 - 276 deleted] [HBB:c.93-22_95del] mutation. These mutations were classified as pathogenic by UniProt Variants confirmed according to the American College of Medical Genetics and Genomics guidelines. These mutations present a phenotype compatible with β⁰-thalassemia, supported by hematological parameters that correlate the degree of reduction in the synthesis of the β-globin chain. Identification of this type of mutation is important for genetic counselling of partners where both are carriers, so that they are aware of the genetic risk of having affected children, allowing them to take an informed decision about their reproductive choices.

Plasma proteome profiling combined with clinical and genetic features reveals the pathophysiological characteristics of β-thalassemia

The phenotype of β-thalassemia underlies multigene interactions, making clinical stratification complicated. An increasing number of genetic modifiers affecting the disease severity have been identified, but are still unable to meet the demand of precision diagnosis. Here, we systematically conducted a comparative plasma proteomic profiling on patients with β-thalassemia and healthy controls. Among 246 dysregulated proteins, 13 core protein signatures with excellent biomarker potential are proposed. The combination of proteome and patients' clinical data revealed patients with codons 41/42 -TTCT mutations have an elevated risk of higher iron burden, dysplasia, and osteoporosis than patients with other genotypes. Notably, 85 proteins correlating to fetal hemoglobin (Hb F) were identified, among which the abundance of 27 proteins may affect the transfusion burden in patients with β-thalassemia. The current study thus provides protein signatures as potential diagnostic biomarkers or therapeutic clues for β-thalassemia.

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246 dysregulated proteins are detected in plasma of patients with β-thalassemia

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13 potential biomarkers and 27 proteins related to disease progression are found

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Variations in plasma proteome reveal the disease pathophysiological characteristics

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Codons 41/42 -TTCT carriers have higher ferritin levels compared to non-carriers

Mortality in β-thalassemia patients with confirmed pulmonary arterial hypertension on right heart catheterization

Pulmonary arterial hypertension (PAH) is a life-threatening complication of β-thalassemia, especially in untransfused patients with thalassemia intermedia. Pinto and colleagues analyzed the outcome of 24 patients with PAH documented by right heart catheterization, and they report that with a median follow-up of 4 years, 54% died, most of which deaths were attributable to PAH. Patients who receive treatment that reduce their pulmonary pressures have improved survival, suggesting that improvement in monitoring and treatment are critical imperatives for these patients.

Immune response and adverse events after vaccination against SARS-CoV-2 in adult patients with transfusion-dependent thalassaemia

Patients with transfusion‐dependent thalassaemia (TDT) are considered an at increased‐risk population for severe and/or morbid coronavirus disease 2019 (COVID‐19) infection. Timely vaccination is the main preventive method for severe COVID‐19. Different adverse events and reactions after vaccination have been reported, with severe ones being extremely rare. Patients with TDT may have altered immunity due to chronic transfusions, iron overload and chelation therapy, and splenic dysfunction. Here, we show that adult patients with TDT following vaccination with the novel messenger RNA vaccines have mild adverse events and can produce protective antibodies comparable to the healthy population.

Heterozygosity of the Complex Corfu δ0β+ Thalassemic Allele (HBD Deletion and HBB:c.92+5G>A) Revisited

The Corfu δ⁰β⁺ thalassemic allele is a unique thalassemic allele consisting of the simultaneous presence in cis of a deletion of the δ-globin (Hemoglobin Subunit Delta, HBD) and a single nucleotide variant in the β-globin gene (Hemoglobin Subunit Beta, HBB). The allele has, so far, been described in individuals of Greek origin. The objectives of the study are to ascertain the prevalence of the Corfu δ⁰β⁺ allele in comparison to other β-thalassemia variants encountered in Greece using our in-house data repository of 2558 β-thalassemia heterozygotes, and to evaluate the hematological phenotype of Corfu δ⁰β⁺ heterozygotes in comparison to heterozygotes with the most common β⁺- and deletion α⁰- thalassemia variants in Greece. The results of the study showed a relative incidence of heterozygotes with Corfu δ⁰β⁺ at 1.56% of all β-thalassemic alleles, and a distinct hematological phenotype of the heterozygotes characterized by microcytic, hypochromic anemia with normal levels of HbA₂ (Hemoglobin A2) and elevated HbF (Hemoglobin F) levels. The application of a specific methodology for the identification of the Corfu δ⁰β⁺ allele is important for precise prenatal and antenatal diagnosis programs in Greece.

Random Forest Clustering Identifies Three Subgroups of β-Thalassemia with Distinct Clinical Severity

In this work, we aimed to establish subgroups of clinical severity in a global cohort of β-thalassemia through unsupervised random forest (RF) clustering. We used a large global dataset of 7910 β-thalassemia patients and evaluated 19 indicators of phenotype severity (IPhS) to determine their contribution and relatedness in grouping β-thalassemia patients into clusters using RF analysis. RF clustering suggested that three clusters with minimal overlapping exist (classification error rate: 4.3%), and six important IPhS were identified: the current age of the patient, the mean serum ferritin level, the age at diagnosis, the age at first transfusion, the age at first iron chelation, and the number of complications. Cluster 3 represented patients with early initiation of transfusion and iron chelation, considerable iron overload, and early mortality from heart failure. Patients in Cluster 2 had lower serum ferritin levels, although they had a higher number of complications manifesting overtime. Patients in Cluster 1 represented a subgroup with delayed or absent transfusion and iron chelation, but with a high morbidity rate. Hepatic disease and cancer were dominant causes of death in patients in Cluster 1 and 2. Our findings established that patients with β-thalassemia can be clustered into three groups based on six parameters of phenotype severity.

A randomised double-blind placebo-controlled clinical trial of oral hydroxyurea for transfusion-dependent β-thalassaemia

Hydroxyurea is an antimetabolite drug that induces fetal haemoglobin in sickle cell disease. However, its clinical usefulness in β-thalassaemia is unproven. We conducted a randomised, double-blind, placebo-controlled clinical trial to evaluate the efficacy and safety of hydroxyurea in transfusion-dependent β-thalassaemia. Sixty patients were assigned 1:1 to oral hydroxyurea 10–20 mg/kg/day or placebo for 6 months by stratified block randomisation. Hydroxyurea treatment did not alter the blood transfusion volume overall. However, a significantly higher proportion of patients on hydroxyurea showed increases in fetal haemoglobin percentage (89% vs. 59%; p < 0.05) and reductions in erythropoietic stress as measured by soluble transferrin receptor concentration (79% vs. 40%; p < 0.05). Based on fetal haemoglobin induction (> 1.5%), 44% of patients were identified as hydroxyurea-responders. Hydroxyurea-responders, required significantly lower blood volume (77 ± SD27ml/kg) compared to hydroxyurea-non-responders (108 ± SD24ml/kg; p < 0.01) and placebo-receivers (102 ± 28ml/kg; p < 0.05). Response to hydroxyurea was significantly higher in patients with HbE β-thalassaemia genotype (50% vs. 0%; p < 0.01) and Xmn1 polymorphism of the γ-globin gene (67% vs. 27%; p < 0.05). We conclude that oral hydroxyurea increased fetal haemoglobin percentage and reduced erythropoietic stress of ineffective erythropoiesis in patients with transfusion-dependent β-thalassaemia. Hydroxyurea reduced the transfusion burden in approximately 40% of patients. Response to hydroxyurea was higher in patients with HbE β-thalassaemia genotype and Xmn1 polymorphism of the γ-globin gene.

Conditioning Regimens in Patients with β-Thalassemia Who Underwent Hematopoietic Stem Cell Transplantation: A Scoping Review

The success of transplant procedures in patients with beta-thalassemia major (β-thalassemia) goes hand-in-hand with improvements in disease knowledge, better supportive care, discoveries in immunogenetics, increase in stem cell sources, and enhancement of conditioning regimens. The aim of this scoping review was to report the evolution of conditioning regimes for β-thalassemia hematopoietic stem cell transplantation. We performed a systematic search for all relevant articles published before July 2021, using the following Medical Subject Headings: "bone marrow transplantation", "stem cell transplantation", "allogeneic", "thalassemia", "β-thalassemia", and "thalassemia major". The final analysis included 52 studies, published between 1988 and 2021, out of 3877 records. The most common conditioning regimen was a combination of busulfan and cyclophosphamide, with successive dose adjustments or remodulation based on patient characteristics. Pre-transplant treatments, reductions in cyclophosphamide dosage, or the adoption of novel agents such as treosulphan all improved overall survival and thalassemia-free survival in transplant-related mortality high-risk patients. Conditioning regimes were modulated for those without a suitable fully matched sibling or unrelated donor, with encouraging results. Hematopoietic stem cell transplantation with haploidentical donors is currently available to virtually all patients with β-thalassemia. However, disparities in outcome are still present around the world. In developing and limited-resource countries, where most diagnoses are focused, transplants are not always available. Therefore, more efforts are needed to close this treatment gap.

Use of Deferasirox Film-Coated Tablets in Pediatric Patients with Transfusion Dependent Thalassemia: A Single Center Experience

Thalassemic syndromes are characterized by clinical heterogenicity. For severe disease forms, lifelong blood transfusions remain the mainstay of therapy, while iron overload monitoring and adequate chelation treatment are required in order to ensure effective disease management. Compared to previous chelators, the new deferasirox film-coated tablet (DFX FCT) is considered to offer a more convenient and well-tolerated treatment scheme, aiming at better treatment-related and patient-related outcomes. The present study’s objective was to prospectively evaluate the safety and efficacy of DFX FCT in children and adolescents with transfusion-dependent thalassemia. Data collected included patient demographics, hematology and biochemistry laboratory work up, magnetic resonance imaging of heart and liver for iron load, as well as ophthalmological and audiological examination prior to and a year following drug administration. Study results confirmed DFX FCT safety in older children in a manner similar to adults, but demonstrated increased frequency of adverse events in younger patients, mainly, involving liver function. With regards to efficacy, study results confirmed the preventive role of DFX FCT in iron loading of liver and heart, however, higher doses than generally recommended were required in order to ensure adequate chelation.

Betibeglogene Autotemcel Gene Therapy for Non-β0/β0 Genotype β-Thalassemia

BACKGROUND

Betibeglogene autotemcel (beti-cel) gene therapy for transfusion-dependent β-thalassemia contains autologous CD34+ hematopoietic stem cells and progenitor cells transduced with the BB305 lentiviral vector encoding the β-globin (β^A-T87Q) gene.

METHODS

In this open-label, phase 3 study, we evaluated the efficacy and safety of beti-cel in adult and pediatric patients with transfusion-dependent β-thalassemia and a non-β⁰/β⁰ genotype. Patients underwent myeloablation with busulfan (with doses adjusted on the basis of pharmacokinetic analysis) and received beti-cel intravenously. The primary end point was transfusion independence (i.e., a weighted average hemoglobin level of ≥9 g per deciliter without red-cell transfusions for ≥12 months).

RESULTS

A total of 23 patients were enrolled and received treatment, with a median follow-up of 29.5 months (range, 13.0 to 48.2). Transfusion independence occurred in 20 of 22 patients who could be evaluated (91%), including 6 of 7 patients (86%) who were younger than 12 years of age. The average hemoglobin level during transfusion independence was 11.7 g per deciliter (range, 9.5 to 12.8). Twelve months after beti-cel infusion, the median level of gene therapy-derived adult hemoglobin (HbA) with a T87Q amino acid substitution (HbA^T87Q) was 8.7 g per deciliter (range, 5.2 to 10.6) in patients who had transfusion independence. The safety profile of beti-cel was consistent with that of busulfan-based myeloablation. Four patients had at least one adverse event that was considered by the investigators to be related or possibly related to beti-cel; all events were nonserious except for thrombocytopenia (in 1 patient). No cases of cancer were observed.

CONCLUSIONS

Treatment with beti-cel resulted in a sustained HbA^T87Q level and a total hemoglobin level that was high enough to enable transfusion independence in most patients with a non-β⁰/β⁰ genotype, including those younger than 12 years of age. (Funded by Bluebird Bio; HGB-207 ClinicalTrials.gov number, NCT02906202.).