In this expert consensus document, different clinical scenarios have been considered and analyzed for the possible impact on treatment outcome. This expert opinion provides dynamic, updatable, priority-based guidance for physicians taking care of transfusion-dependent β-thalassemia (TDT) patients Key points: - Clinical management of TDT patients is still based on chronic transfusion combined with iron chelation therapy. Allogeneic hematopoietic stem cell transplantation (HSCT) potentially provides a cure, but few patients have an HLA-identical sibling, and optimal results are reported in patients ≤ 14 years. - The European Hematology Association (EHA), through the EHA Scientific Working Group on Red Cells/Iron and the European Bone Marrow Transplantation (EBMT) group, has updated a 2021 EHA decision-making algorithm on evidence and expert consensus with the aim of identifying which patients with TDT could benefit from gene therapy (GT). - The lower age limit. For the time being, they strictly follow the regulatory authority (The Food and Drug Administration and European Medicines Agency) indications as follows: Gene addition (GA) therapy to patients ≥4 years and gene editing (GE) therapy to patients ≥12 years of age. See Figure 1 in original paper. - The upper age limit. The panel recommends limiting access to GT for patients above the age of 35 years. The panel agrees that any GT approach beyond the age of 35 years (upper age limit in clinical trials of GE therapy) should be treated as an exceptional case, under the principle of gradualness only in selected centers with large experience and qualification in the delivery of GT and/or HSCT in TDT. - The best transplant outcomes in β-TDT are achieved in patients <14 years old with an HLA-identical donor (related or unrelated). - In TDT patients, haploidentical transplantation is an emerging alternative, requiring further studies to optimize protocols and to optimize long-term safety and efficacy. - Advances in graft-versus-host disease prophylaxis strategies continue to refine transplantation approaches, which may, in the future, result in broader access to HSCT for patients without an HLA-matched donor. - Outcomes of HSCT in adulthood require improvements even in the context of a fully matched sibling, and a careful case-by-case discussion. - Beta and alpha globin genotypes must be assessed in all patients prior to proceeding with GT. - Patients should not be excluded from GT therapy based on beta genotypes. - Currently, patients with alpha globin gene multiplication should not be considered as eligible for GT. - Ineligible patients (See Table 2 in original paper). - Patients with liver fibrosis and iron overload within the following characteristics: —Liver stiffness measurement (LSM )≥8kpPa independently from liver iron concentration (LIC). —LSM <8kPa and LIC >7–14mg/dry weight (dw) without a 6–12-month period of regular and consistent iron chelation to decrease LIC ≤7 mg/g dw. —LSM <8kPa and LIC ≥15mg/g dw (situation to be re-evaluated by liver biopsy, temporarily not eligible) ● Patients with severe myocardial iron overload demonstrated by a T2 magnetic resonance imaging <10ms documented in the previous 6 months. ● Pulmonary hypertension (determined by cardiac catheterization). ● Patients with chronic organ damage, hepatopathy, insulin-dependent diabetes, nephropathy and positive thrombophilic status. |