Clinical Report: Gene Therapy for Transfusion-Dependent Thalassemia

Overview

A joint EHA–EBMT consensus updates criteria for selecting patients with transfusion-dependent thalassemia (TDT) for gene therapy, incorporating newer treatments, transplantation experience, and clinical-study follow-up. Its proposed algorithm gives central importance to cumulative liver disease and also considers other organ complications, iron overload, thrombophilic status, and age. The authors emphasize that longer follow-up and additional treated-patient data are needed to clarify long-term outcomes.

Background

TDT is a globally distributed monogenic red-cell disorder, with more than 1.3 million cases estimated worldwide by the Global Burden of Disease study. Although advances in care have improved prevalence and mortality, TDT continues to affect quality of life and survival; management has largely relied on chronic transfusions and iron chelation, with luspatercept and mitapivat adding therapeutic options. The source identifies allogeneic hematopoietic cell transplantation and gene therapy as curative treatments, and notes that currently available gene therapy uses fully myeloablative conditioning. The EHA–EBMT panel updated earlier guidance to address treatment advances and to refine candidate selection using evidence from transplantation, gene-therapy studies, and TDT-related organ complications.

Data Highlights

Key Findings

• The EHA–EBMT consensus updates the 2021 EHA/SITE document on gene addition and addresses newly available treatments, hematopoietic cell transplantation data, and clinical studies of gene addition and gene editing in TDT.

• The panel used experience from allogeneic transplantation to inform prioritization criteria, noting that current gene therapy involves fully myeloablative conditioning and may be considered analogous to autologous transplantation.

• The revised selection flow chart makes liver disease a central element. The panel describes hepatic fibrosis as a marker of accumulated oxidative stress and recommends considering the cumulative history of liver disease, including iron accumulation and chelation, hepatitis infection, alcohol consumption, and metabolic disorders.

• The consensus identifies some patients for invasive liver evaluation, specifically biopsy, before gene therapy and states that biopsy specimens must meet standards of accuracy and representativeness.

• Selection also takes account of cardiomyopathy, endocrinopathy, nephropathy, thrombophilic status, organ damage, iron overload, and age, including distinctions between noneligible patients and possible future candidates.

• The authors state that additional follow-up is needed to clarify gene therapy’s effect on survival relative to the healthy population and established transplantation approaches; related reporting on exagamglogene autotemcel describes ongoing pediatric studies in children aged 5–11, while noting that the therapy is approved for patients aged 12 years and older in that report.

Clinical Implications

The consensus supports structured, individualized candidate assessment that includes cumulative liver injury and other organ complications before gene therapy, with liver biopsy considered for patients identified as requiring invasive evaluation. The source also emphasizes that gene-therapy follow-up remains limited and that longer observation and more patient data are needed to assess survival outcomes.

Conclusion

The EHA–EBMT consensus provides an updated framework for prioritizing TDT patients for gene therapy, with liver disease and broader organ status central to assessment. The authors identify longer-term follow-up as necessary to clarify the durability and survival outcomes of treatment.

Related Resources & Content

1. EHA Specialized Working Group and EBMT Hemoglobinopathies Working Party, PubMed, 2026 -- Update of the decision-making algorithm on selecting transfusion-dependent β-thalassemic patients for gene therapy approaches: joint consensus report

2. The Medicine Maker, 2025 -- This Week’s CGT News: Vertex’s Gene Therapies Show Promise in Younger Children

3. American Journal of Hematology, year not stated -- Correction of Ineffective Erythropoiesis and Normalization of Iron Homeostasis After Exagamglogene Autotemcel in Transfusion-Dependent β-Thalassemia

4. Bone Marrow Transplantation — Understanding Gene Addition and Editing Strategies for Sickle Cell Disease: Insights from the EHA-EBMT Consensus Document

5. the medicine maker — Gene Therapies for Newborns

6. Update of the decision-making algorithm on selecting transfusion-dependent β-thalassemic patients for gene therapy approaches: joint consensus report

7. This Week’s CGT News: Vertex’s Gene Therapies Show Promise in Younger Children

8. Correction of Ineffective Erythropoiesis and Normalization of Iron Homeostasis After Exagamglogene Autotemcel in Transfusion-Dependent β-Thalassemia

9. Update of the decision-making algorithm on selecting transfusion-dependent β-thalassemic patients for gene therapy approaches: joint consensus report on behalf of EHA-specialized working group and EBMT hemoglobinopathies working party.

10. Long-term efficacy and safety results of betibeglogene autotemcel gene therapy for transfusion-dependent β-thalassemia - PubMed

11. Durable Clinical Benefits with Exagamglogene Autotemcel for Transfusion-Dependent β-Thalassemia | Blood | American Society of Hematology