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

Gene therapy in pediatrics - Clinical studies and approved drugs (as of 2023)

Gene therapy in pediatrics represents a cutting-edge therapeutic strategy for treating a range of genetic disorders that manifest in childhood. Gene therapy involves the modification or correction of a mutated gene or the introduction of a functional gene into a patient's cells. In general, it is implemented through two main modalities namely ex vivo gene therapy and in vivo gene therapy. Currently, a noteworthy array of gene therapy products has received valid market authorization, with several others in various stages of the approval process. Additionally, a multitude of clinical trials are actively underway, underscoring the dynamic progress within this field. Pediatric genetic disorders in the fields of hematology, oncology, vision and hearing loss, immunodeficiencies, neurological, and metabolic disorders are areas for gene therapy interventions. This review provides a comprehensive overview of the evolution and current progress of gene therapy-based treatments in the clinic for pediatric patients. It navigates the historical milestones of gene therapies, currently approved gene therapy products by the U.S. Food and Drug Administration (FDA) and/or European Medicines Agency (EMA) for children, and the promising future for genetic disorders. By providing a thorough compilation of approved gene therapy drugs and published results of completed or ongoing clinical trials, this review serves as a guide for pediatric clinicians to get a quick overview of the situation of clinical studies and approved gene therapy products as of 2023.

Ferroptosis as an emerging target in sickle cell disease

Sickle cell disease (SCD) is an inherited hemoglobin disorder marked by red blood cell sickling, resulting in severe anemia, painful episodes, extensive organ damage, and shortened life expectancy. In SCD, increased iron levels can trigger ferroptosis, a specific type of cell death characterized by reactive oxygen species (ROS) and lipid peroxide accumulation, leading to damage and organ impairments. The intricate interplay between iron, ferroptosis, inflammation, and oxidative stress in SCD underscores the necessity of thoroughly understanding these processes for the development of innovative therapeutic strategies. This review highlights the importance of balancing the complex interactions among various factors and exploitation of the knowledge in developing novel therapeutics for this devastating disease.

Prenatal Diagnosis of Cystic Fibrosis by Celocentesis

Celocentesis is a new sampling tool for prenatal diagnosis available from 7 weeks in case of couples at risk for genetic diseases. In this study, we reported the feasibility of earlier prenatal diagnosis by celocentesis in four cases of cystic fibrosis and one case of cystic fibrosis and β-thalassemia co-inherited in the same fetus. Celomic fluids were aspired from the celomic cavity between 8+2 and 9+3 weeks of gestation and fetal cells were picked up by micromanipulator. Maternal DNA contamination was tested and target regions of fetal DNA containing parental pathogenetic variants of CFTR and HBB genes were amplified and sequenced. Four of the five fetuses resulted as being affected by cystic fibrosis and, in all cases, the women decided to interrupt the pregnancy. In the other case, the fetus presented a healthy carrier of cystic fibrosis. The results were confirmed in three cases on placental tissue. In one case, no abortive tissue was obtained. In the last case, the woman refused the prenatal diagnosis to confirm the celocentesis data; the pregnancy is ongoing without complications. This procedure provides prenatal diagnosis of monogenic diseases at least four weeks earlier than traditional procedures, reducing the anxiety of patients and providing the option for medical termination of the affected fetus at 8-10 weeks of gestation, which is less traumatic and safer than surgical termination in the second trimester.

Aerobic physical capacity and health-related quality of life in children with sickle cell disease

BACKGROUND

Aerobic fitness is a predictor of cardiovascular health which correlates with health-related quality of life in the general population. The aim is to evaluate the aerobic capacity by cardiopulmonary exercise test (CPET) in children with sickle cell disease in comparison with healthy matched controls.

METHODS

Controlled cross-sectional study.

RESULTS

A total of 72 children (24 with sickle cell disease and 48 healthy controls), aged 6-17 years old were enrolled. Children with sickle cell disease had a poor aerobic capacity, with median VO2max Z-score values significantly lower than matched controls (-3.55[-4.68; -2.02] vs. 0.25[-0.22; 0.66], P < 0.01, respectively), and a high proportion of 92% children affected by an impaired aerobic capacity (VO2max Z-score < -1.64). The VO2max decrease was associated with the level of anemia, the existence of a homozygote HbS/S mutation, restrictive lung disease and health-related quality of life.

CONCLUSION

Aerobic capacity is poor in children with sickle cell disease. VO2max decrease is associated with the level of anemia, the existence of a homozygote HbS/S mutation, lung function, and health-related quality of life. These results represent a signal in favor of early initiation of cardiac rehabilitation in patients with sickle cell disease.

CLINICAL TRIALS

NCT05995743.

IMPACT

Aerobic fitness is a predictor of cardiovascular health which correlates with health-related quality of life in the general population. Aerobic capacity (VO2max) is poor in children with sickle cell disease, despite the absence of any pattern of heart failure. VO2max decrease was associated with the level of anemia, the existence of a homozygote HbS/S mutation, restrictive lung disease, and health-related quality of life. These results are in favor of early initiation of cardiac rehabilitation in children with sickle cell disease.

Emerging Gene Therapeutics for Epidermolysis Bullosa under Development

The monogenetic disease epidermolysis bullosa (EB) is characterised by the formation of extended blisters and lesions on the patient's skin upon minimal mechanical stress. Causal for this severe condition are genetic mutations in genes, leading to the functional impairment, reduction, or absence of the encoded protein within the skin's basement membrane zone connecting the epidermis to the underlying dermis. The major burden of affected families justifies the development of long-lasting and curative therapies operating at the genomic level. The landscape of causal therapies for EB is steadily expanding due to recent breakthroughs in the gene therapy field, providing promising outcomes for patients suffering from this severe disease. Currently, two gene therapeutic approaches show promise for EB. The clinically more advanced gene replacement strategy was successfully applied in severe EB forms, leading to a ground-breaking in vivo gene therapy product named beremagene geperpavec (B-VEC) recently approved from the US Food and Drug Administration (FDA). In addition, the continuous innovations in both designer nucleases and gene editing technologies enable the efficient and potentially safe repair of mutations in EB in a potentially permanent manner, inspiring researchers in the field to define and reach new milestones in the therapy of EB.

Drug Design and Development for Rare Hematologic Diseases

The last decade has seen an exponential increase in therapeutic options for rare hematologic diseases [...].

Health-Related Quality-of-Life Profile of Pediatric Patients with β Thalassemia after Hematopoietic Stem Cell Transplantation

Matched hematopoietic stem cell transplantation (HSCT) is a feasible and curative treatment in pediatric patients with beta thalassemia major (β-TM). However, little data are available regarding patients and their parents' health-related quality of life (HRQoL) after the procedure. As such, we investigated the HRQoL of pediatric patients with β-TM after HSCT compared to that of patients treated with blood transfusions and iron chelation. The health-related quality of life of 43 β-TM pediatric patients and 43 parents were evaluated using the Pediatric Quality of Life Inventory (PedsQL). A total of 25 patients underwent HSCT: 15 from a sibling and 10 from an HLA-matched donor. The median follow-up time from HSCT was 5 years (range 1-13 years). The mean ages at the survey were 10.1 years (range 5-15) and 9.6 years (range 5-15) for transfused and transplanted patients, respectively. A significant reduction in HRQoL was reported in the group of transfused patients compared with that of patients transplanted in the following PedsQL domains: children's and parents' physical functions, Δ = -15.4, p = 0.009 and Δ = -11.3, p = 0.002, respectively; children's and parents' emotional functioning, Δ = -15.2, p = 0.026 and Δ = -15.2, p = 0.045, respectively; child's and parents' school functioning, Δ = -25, p = 0.005 and Δ = -22.5, p = 0.011, respectively; total child and parents scores, Δ = -14.5, p = 0.004 and Δ = -13.2, p = 0.005, respectively. The results of a multivariable analysis showed that the HSCT procedure was significantly associated with a higher total child PedsQL score (adjusted mean difference = 15.3, p = 0.001) and a higher total parent PedsQL score (adjusted mean difference = 14.1, p = 0.006). We found no significant difference in the HRQoL measured after sibling or unrelated human leukocyte antigen (HLA)-matched HSCT. Finally, a significant positive correlation across all the PedsQL domains was found between the scores reported by the children and those reported by their parents. In conclusion, our study shows that HSCT in pediatric patients with β-TM is associated with a good overall HRQoL profile. This information further supports physicians when counseling patients and their parents before the HSCT procedure.

Evolution of CRISPR/Cas Systems for Precise Genome Editing

The bacteria-derived CRISPR/Cas (an acronym for regularly interspaced short palindromic repeats/CRISPR-associated protein) system is currently the most widely used, versatile, and convenient tool for genome engineering. CRISPR/Cas-based technologies have been applied to disease modeling, gene therapies, transcriptional modulation, and diagnostics. Nevertheless, some challenges remain, such as the risk of immunological reactions or off-target effects. To overcome these problems, many new methods and CRISPR/Cas-based tools have been developed. In this review, we describe the current classification of CRISPR systems and new precise genome-editing technologies, summarize the latest applications of this technique in several fields of research, and, finally, discuss CRISPR/Cas system limitations, ethical issues, and challenges.