Davide Ciriaco

Background: β-haemoglobinopathies, including sickle cell disease and transfusion-dependent β-thalassaemia, are among the most common monogenic disorders worldwide and represent a major global health burden. Conventional treatments, such as blood transfusions, iron chelation, fetal haemoglobin induction, and allogeneic haematopoietic stem cell transplantation, have improved outcomes but remain limited by treatment-related toxicity, donor availability, and incomplete curative potential. Methods: A narrative literature review was conducted using PubMed up to 2025. Search terms included “sickle cell disease,” “sickle cell anemia,” “β-thalassemia,” “transfusion-dependent beta-thalassemia,” “gene therapy,” “gene addition,” “gene editing,” “CRISPR-Cas9,” “lentiviral vector,” “children,” “paediatric,” and “pediatric.” Relevant clinical trials, reviews, consensus statements, and guidelines were selected and qualitatively analysed. Results: Gene therapy for β-haemoglobinopathies is based mainly on two strategies: gene addition and gene editing. Gene addition uses lentiviral vectors to introduce functional or modified β-globin genes into autologous haematopoietic stem cells, whereas gene editing targets regulatory pathways, particularly BCL11A, to reactivate fetal haemoglobin synthesis or correct disease-causing mutations. Clinical studies have shown encouraging outcomes, including transfusion independence in many patients with β-thalassaemia and marked reduction or elimination of vaso-occlusive crises in sickle cell disease. Paediatric and adolescent data are increasingly promising, although still limited. Conclusions: Gene therapy is reshaping the treatment landscape of β-haemoglobinopathies by offering a personalised and potentially curative approach. However, long-term safety, conditioning toxicity, fertility preservation, accessibility, costs, and implementation in high-prevalence regions remain critical challenges. Further studies are needed to optimise patient selection and expand equitable access.

Background: β-haemoglobinopathies, including sickle cell disease and transfusion-dependent β-thalassaemia, are among the most common monogenic disorders worldwide and represent a major global health burden. Conventional treatments, such as blood transfusions, iron chelation, fetal haemoglobin induction, and allogeneic haematopoietic stem cell transplantation, have im-proved outcomes but remain limited by treatment-related toxicity, donor availability, and incom-plete curative potential. Methods: A narrative literature review was conducted using PubMed up to 2025. Search terms included “sickle cell disease,” “sickle cell anemia,” “β-thalassemia,” “transfu-sion-dependent beta-thalassemia,” “gene therapy,” “gene addition,” “gene editing,” “CRISPR-Cas9,” “lentiviral vector,” “children,” “paediatric,” and “pediatric.” Relevant clinical tri-als, reviews, consensus statements, and guidelines were selected and qualitatively analysed. Results: Gene therapy for β-haemoglobinopathies is based mainly on two strategies: gene addition and gene editing. Gene addition uses lentiviral vectors to introduce functional or modified β-globin genes into autologous haematopoietic stem cells, whereas gene editing targets regulatory pathways, particu-larly BCL11A, to reactivate fetal haemoglobin synthesis or correct disease-causing mutations. Clin-ical studies have shown encouraging outcomes, including transfusion independence in many pa-tients with β-thalassaemia and marked reduction or elimination of vaso-occlusive crises in sickle cell disease. Paediatric and adolescent data are increasingly promising, although still limited. Conclu-sion: Gene therapy is reshaping the treatment landscape of β-haemoglobinopathies by offering a personalised and potentially curative approach. However, long-term safety, conditioning toxicity, fertility preservation, accessibility, costs, and implementation in high-prevalence regions remain critical challenges. Further studies are needed to optimise patient selection and expand equitable access.

Sickle cell disease (SCD) is the most common monogenic disorder worldwide and remains a major cause of morbidity and mortality. Sickle cell anemia (SCA), the homozygous HbSS genotype, represents the most severe and frequent form within the spectrum of SCD. Hydroxyurea (HU), a ribonucleotide reductase inhibitor, represents the first and most widely used disease-modifying therapy for SCA. This review summarizes current evidence on the mechanisms of action, clinical efficacy, systemic effects, and long-term safety of chronic HU therapy in patients with SCA. A comprehensive literature search was conducted in PubMed up to 2025 using the terms “sickle cell disease,” “sickle cell anemia”, “hydroxyurea,” and “children” or “paediatric.” Eligible studies included randomized controlled trials, cohort studies, and systematic reviews evaluating HU therapy in SCA. Literature analysis showed that HU exerts pleiotropic effects by inducing fetal hemoglobin (HbF) synthesis, improving red blood cell deformability, reducing leukocyte and platelet counts, and enhancing nitric oxide bioavailability. These mechanisms lead to decreased vaso-occlusive crises, acute chest syndrome, transfusion requirements, and overall mortality. Beyond hematologic improvement, HU confers neuroprotective benefits, modulates inflammatory and immune pathways, and supports normal growth and endocrine development in children. Adverse events, primarily mild bone marrow suppression, are dose-dependent and reversible with appropriate monitoring. No evidence supports an increased risk of malignancy with long-term use. In conclusion, chronic HU therapy is a safe, effective, and multifaceted treatment that substantially improves survival and quality of life in patients with SCA. Early initiation and individualized dosing maximize its therapeutic benefits and help prevent irreversible organ damage.