Overall and complication-free survival in a large cohort of patients with β-thalassemia major followed over 50 years

Mortality, Clinical Complications, and Healthcare Resource Utilization Associated with Managing Transfusion-Dependent β-Thalassemia and Sickle Cell Disease with Recurrent Vaso-occlusive Crises in Italy

OBJECTIVE

To examine the clinical burden and healthcare resource utilization (HCRU) among patients with transfusion-dependent β-thalassemia (TDT) and patients with sickle cell disease (SCD) with recurrent vaso-occlusive crises (VOCs) in Italy.

METHODS

Eligible patients were identified from an administrative claims database from 1 January 2010 and 1 February 2019. Patients with TDT had ≥ 1 iron chelation treatment, ≥ 8 red blood cell transfusions (RBCTs) during any 12-month period, and ≥ 12 months of available data pre- and post-index (i.e., first RBCT claim). Patients with SCD with recurrent VOCs had ≥ 2 VOCs/year in ≥ 2 consecutive years and ≥ 12 months of available data pre- and post-index (second VOC claim in the second of 2 consecutive years). Patients were propensity score matched to five controls by age, sex, geographic area, and index year. Clinical and HCRU outcomes were evaluated post-index.

RESULTS

In total, 214 patients with TDT and 111 patients with SCD with recurrent VOCs were matched to 1070 and 555 controls, respectively. Both patient groups had substantially higher mortality rates than controls (TDT: 4.8 versus 0.8 deaths per 100 person-years; SCD: 1.6 versus 0.4 deaths per 100 person-years). Clinical complications were prevalent in both patient groups. Compared with controls, both patient groups had significantly higher mean rates of all-cause hospitalizations (TDT: 1.4 versus 0.1; SCD: 2.0 versus 0.1) and outpatient services (TDT: 21.9 versus 1.6; SCD: 6.2 versus 1.0) per patient per year (all: p < 0.05).

CONCLUSIONS

Management of TDT and SCD in Italy is associated with significant clinical and health system burden, highlighting the need for new treatments that eliminate RBCTs and VOCs.

Anemia and iron overload as prognostic markers of outcomes in β-thalassemia

INTRODUCTION

Ineffective erythropoiesis and subsequent anemia as well as primary and secondary (transfusional) iron overload are key drivers for morbidity and mortality outcomes in patients with β-thalassemia.

AREAS COVERED

In this review, we highlight evidence from observational studies evaluating the association between measures of anemia and iron overload versus outcomes in both non-transfusion-dependent and transfusion-dependent forms of β-thalassemia.

EXPERT OPINION

Several prognostic thresholds have been identified with implications for patient management. These have also formed the basis for the design of novel therapy clinical trials by informing eligibility and target endpoints. Still, several data gaps persist in view of the challenge of assessing prospective long-term outcomes in a chronic disease. Pooling insights on the prognostic value of different measures of disease mechanism will be key to design future scoring systems that can help optimize patient management.

Causes of Death and Mortality Trends in Individuals with Thalassemia in the United States, 1999-2020

Purpose

Our study aims to describe the mortality trends and disparities among individuals with thalassemia in the United States (US).

Patients and Methods

We used CDC WONDER database to calculate the age-adjusted mortality rates (AAMRs) per 1,000,000 individuals and used the Joinpoint Regression Program to measure the average annual percent change (AAPC). Subgroup evaluations were performed by sex, age, race, census region, and urbanization level.

Results

From 1999 to 2020, there were 2797 deaths relatd to thalassemia in the US. The AAMR of thalassemia-related death showed a decreasing trend from 0.50 (95% CI, 0.41-0.58) in 1999 to 0.48 (95% CI, 0.41-0.55) in 2020 with the AAPC of -1.42 (95% CI, -2.42, -0.42). Asians have the highest AAMR (1.34 [95% CI, 1.20-1.47]), followed by non-Hispanic Blacks (0.65 [95% CI, 0.59-0.71]), non-Hispanic Whites (0.32 [95% CI, 0.30-0.33]), and Hispanics (0.11 [95% CI, 0.08-0.14]). Cardiovascular disease remains the leading cause of death among individuals with thalassemia. The urban population has a higher AAMR than the rural population (0.43 [95% CI, 0.41-0.45] vs 0.29 [95% CI, 0.26-0.32]).

Conclusion

Our study calls for targeted interventions to address the racial and geographic disparities existed among individuals of thalassemia in the US.

Iron chelation therapy for children with transfusion-dependent β-thalassemia: How young is too young?

In this review, we provide a summary of evidence on iron overload in young children with transfusion-dependent β-thalassemia (TDT) and explore the ideal timing for intervention. Key data from clinical trials and observational studies of the three available iron chelators deferoxamine, deferiprone, and deferasirox are also evaluated for inclusion of subsets of young children, especially those less than 6 years of age. Evidence on the efficacy and safety of iron chelation therapy for children ≥2 years of age with transfusional iron overload is widely available. New data exploring the risks and benefits of early-start iron chelation in younger patients with minimal iron overload are also emerging.

Revisiting iron overload status and change thresholds as predictors of mortality in transfusion-dependent β-thalassemia: a 10-year cohort study

Data on iron overload status and change thresholds that can predict mortality in patients with transfusion-dependent β-thalassemia (TDT) are limited. This was a retrospective cohort study of 912 TDT patients followed for up to 10 years at treatment centers in Italy (median age 32 years, 51.6% female). The crude mortality rate was 2.9%. Following best-predictive threshold identification through receiver operating characteristic curve analyses, data from multivariate Cox-regression models showed that patients with Period Average Serum Ferritin (SF) > 2145 vs ≤ 2145 ng/mL were 7.1-fold (P < 0.001) or with Absolute Change SF > 1330 vs ≤ 1330 ng/mL increase were 21.5-fold (P < 0.001) more likely to die from any cause. Patients with Period Average Liver Iron Concentration (LIC) > 8 vs ≤ 8 mg/g were 20.2-fold (P < 0.001) or with Absolute Change LIC > 1.4 vs ≤ 1.4 mg/g increase were 27.6-fold (P < 0.001) more likely to die from any cause. Patients with Index (first) cardiac T2* (cT2*) < 27 vs ≥ 27 ms were 8.6-fold (P < 0.001) more likely to die from any cause. Similarly, results at varying thresholds were identified for death from cardiovascular disease. These findings should support decisions on iron chelation therapy by establishing treatment targets, including safe iron levels and clinically meaningful changes over time.

Differential effects of iron chelators on iron burden and long-term morbidity and mortality outcomes in a large cohort of transfusion-dependent β-thalassemia patients who remained on the same monotherapy over 10 years

We conducted a retrospective cohort study on 663 transfusion-dependent β-thalassemia patients receiving the same iron chelation monotherapy with deferoxamine, deferiprone, or deferasirox for up to 10 years (median age 31.8 years, 49.9 % females). Patients on all three iron chelators had a steady and significant decline in serum ferritin over the 10 years (median deferoxamine: -170.7 ng/mL, P = 0.049, deferiprone: -236.7 ng/mL, P = 0.001; deferasirox: -323.7 ng/mL, P < 0.001) yet had no significant change in liver iron concentration or cardiac T2*; while noting that patients generally had low hepatic and cardiac iron levels at study start. Median absolute, relative, and normalized changes were generally comparable between the three iron chelators. Patients receiving deferasirox had the highest morbidity and mortality-free survival probability among the three chelators, although the difference was only statistically significant when compared with deferoxamine (P = 0.037). On multivariate Cox regression analysis, there was no significant association between iron chelator type and the composite outcome of morbidity or mortality. In a real-world setting, there is comparable long-term iron chelation effectiveness between the three available iron chelators for patients with mild-to-moderate iron overload.

Association between Epicardial Adipose Tissue and Atrial Fibrillation in Patients with Transfusion-Dependent β-Thalassemia

Background: Modern treatments for transfusion-dependent β-thalassemia (TDβT) have allowed patients to reach high life expectancy with no iron overload. Despite survival improvement, atrial fibrillation (AF) has emerged as a relevant issue. AF pathophysiology and characteristics in TDβT are different than in the general population. Epicardial adipose tissue (EAT) may play a role but its relationship with AF in patients with TDβT has not been explored. Methods: A monocentric, cross-sectional study, enrolling consecutive patients with TDβT. Epicardial adipose tissue (EAT) was evaluated at magnetic resonance. Characteristics of patients with and without history of AF were investigated. Factors independently associated with AF prevalence were analyzed. Results: A total of 116 patients were enrolled. All patients were treated with regular chelation therapy. The prevalence of AF was 29.3% (34/116). Cardiac T2* and liver iron concentration were no different between patients with and without AF. EAT thickness was significantly higher in patients with AF at left atrium, right atrium and right ventricle (5.0 vs. 4.0 mm, p < 0.01, 4.4 vs. 4.0, p = 0.02 and 5.0 vs. 4.3, p = 0.04). Patients with AF presented with older age, (53 vs. 49 years, p < 0.01), more hypothyroidism (44.1 vs. 20.7%, p = 0.01), pulmonary hypertension (23.5 vs. 2.4% p < 0.01), splenectomy (88.2 vs. 64.6%, p = 0.01), higher right and left atrial volume (61 vs. 40 and 74 vs. 43 mL, both p < 0.01). At multivariable analysis, hypothyroidism, left atrial volume and left atrial EAT were independently associated with AF (odds ratio 9.95, 1.09 and 1.91, respectively). Conclusions: In a contemporary cohort of patients with TDβT, treated with regular chelation therapy, prevalence of AF was unrelated to iron overload. EAT was independently associated with AF.

Quality of life, mood disorders, and cognitive impairment in adults with β-thalassemia

Advances in understanding the disease process in β-thalassemia supported development of various treatment strategies that resulted in improved survival. Improved survival, however, allowed multiple morbidities to manifest and cemented the need for frequent, lifelong treatment. This has directly impacted patients' health-related quality of life and opened the door for various psychiatric and cognitive disorders to potentially develop. In this review, we summarize available evidence on quality of life, depression and anxiety, suicidality, and cognitive impairment in adult patients with β-thalassemia while sharing our personal insights from experience in treating patients with both transfusion-dependent and non-transfusion-dependent forms.

Defining curative endpoints for transfusion-dependent β-thalassemia in the era of gene therapy and gene editing

β-thalassemia is a monogenic disease that results in varying degrees of anemia. In the most severe form, known as transfusion-dependent β-thalassemia (TDT), the clinical hallmarks are ineffective erythropoiesis and a requirement of regular, life-long red blood cell transfusions, with the development of secondary clinical complications such as iron overload, end-organ damage, and a risk of early mortality. With the exception of allogeneic hematopoietic cell transplantation, current treatments for TDT address disease symptoms and not the underlying cause of disease. Recently, a growing number of gene addition and gene editing-based treatments for patients with TDT with the potential to provide a one-time functional cure have entered clinical trials. A key challenge in the design and evaluation of these trials is selecting endpoints to evaluate if these novel genetic therapies have a curative versus an ameliorative effect. Here, we present an overview of the pathophysiology of TDT, review emerging gene addition or gene editing therapeutic approaches for TDT currently in clinical trials, and identify a series of endpoints that can quantify therapeutic effects, including a curative outcome.

Αlpha-thalassemia: A practical overview

α-Thalassemia is an inherited blood disorder characterized by decreased synthesis of α-globin chains that results in an imbalance of α and β globin and thus varying degrees of ineffective erythropoiesis, decreased red blood cell (RBC) survival, chronic hemolytic anemia, and subsequent comorbidities. Clinical presentation varies depending on the genotype, ranging from a silent or mild carrier state to severe, transfusion-dependent or lethal disease. Management of patients with α-thalassemia is primarily supportive, addressing either symptoms (eg, RBC transfusions for anemia), complications of the disease, or its transfusion-dependence (eg, chelation therapy for iron overload). Several novel therapies are also in development, including curative gene manipulation techniques and disease modifying agents that target ineffective erythropoiesis and chronic hemolytic anemia. This review of α-thalassemia and its various manifestations provides practical information for clinicians who practice beyond those regions where it is found with high frequency.

Management of transfusion-dependent β-thalassemia (TDT): Expert insights and practical overview from the Middle East

β-Thalassemia is one of the most common monogenetic diseases worldwide, with a particularly high prevalence in the Middle East region. As such, we have developed long-standing experience with disease management and devising solutions to address challenges attributed to resource limitations. The region has also participated in the majority of clinical trials and development programs of iron chelators and more novel ineffective erythropoiesis-targeted therapy. In this review, we provide a practical overview of management for patients with transfusion-dependent β-thalassemia, primarily driven by such experiences, with the aim of transferring knowledge to colleagues in other regions facing similar challenges.

Cardiac complications in thalassemia throughout the lifespan: Victories and challenges

Thalassemias are among the most common hereditary diseases in the world because heterozygosity offers protection against malarial infection. Affected individuals have variable expression of alpha or beta chains that lead to their unbalanced utilization during hemoglobin formation, oxidative stress, and apoptosis of red cell precursors prior to maturation. Some individuals produce sufficient hemoglobin to survive but suffer the vascular stress imposed by chronic anemia and ineffective erythropoiesis. In other patients, mature red cell formation is insufficient, and chronic transfusions are required-suppressing anemia and ineffective erythropoiesis but at the expense of iron overload. The cardiovascular consequences of thalassemia have changed dramatically over the previous five decades because of evolving treatment practices. This review summarizes this evolution, focusing on complications and management pertinent to modern patient cohorts.

Sickle cell disease and acute leukemia: one case report and an extensive review

Population-based studies and case reports suggest that there may be an increased risk of acute leukemia associated with sickle cell disease (SCD). Following the description of a new case report, an extensive review of the literature identified 51 previously described cases. Most cases study showed myelodysplastic features confirmed, when available, by genetic markers such as chromosome 5 and/or chromosome 7 abnormalities and TP53 gene mutations. The increased risk of leukemogenesis is certainly multifactorial and related to the pathophysiologic mechanisms of the clinical manifestations of SCD. Chronic hemolysis and secondary hemochromatosis may cause increased chronic inflammation, resulting in persistent marrow stress, which could potentially compromise the genomic stability of the hematopoietic stem cells generating genomic damage and somatic mutations over the course of SCD and its treatment, resulting in a clone that led to acute myeloid leukemia.

Therapeutic perspective for children and young adults living with thalassemia and sickle cell disease

Hemoglobinopathies, including thalassemias and sickle cell disease, are the most common monogenic diseases worldwide, with estimated annual births of more than 330,000 affected infants. Hemoglobin disorders account for about 3.4% of deaths in children under 5 years of age. The distribution of these diseases is historically linked to current or previously malaria-endemic regions; however, immigration has led to a worldwide distribution of these diseases, making them a global health problem. During the last decade, new treatment approaches and novel therapies have been proposed, some of which have the potential to change the natural history of these disorders. Indeed, the first erythroid maturation agent, luspatercept, and gene therapy have been approved for beta-thalassemia adult patients. For sickle cell disease, molecules targeting vaso-occlusion and hemoglobin S polymerization include crizanlizumab, which has been approved for patients ≥ 16 years, voxelotor approved for patients ≥ 12 years, and L-glutamine for patients older than 5 years.    Conclusion: We herein present the most recent advances and future perspectives in thalassemia and sickle cell disease treatment, including new drugs, gene therapy, and gene editing, and the current clinical trial status in the pediatric populations. What is Known: • Red blood cell transfusions, iron chelation therapy and hematopoietic stem cell transplantation have been the mainstay of treatment of thalassemia patients for decades. • For sickle cell disease, until 2005, treatment strategies were mostly the same as those for thalassemia, with the option of simple transfusion or exchange transfusion. In 2007, hydroxyurea was approved for patients ≥ 2 years old. What is New: • In 2019, gene therapy with betibeglogene autotemcel (LentiGlobin BB305) was approved for TDT patients ≥ 12 years old non β0/β0 without matched sibling donor. • Starting from 2017 several new drugs, such as L-glutamine (approved only by FDA), crizanlizumab (approved by FDA and EMA for patients ≥ 16 years), and lastly voxelotor (approved by FDA and EMA for patients ≥ 12 years old).