Alpha-thalassemia is a severe inherited hemoglobin disorder with limited curative options for transfusion-dependent patients lacking suitable donors. We report the first-in-human application of lentiviral vector-mediated α-globin gene therapy in a 14-year-old girl with transfusion-dependent Hemoglobin H disease (--SEA/αCSα). Autologous CD34+ hematopoietic stem and progenitor cells were mobilized, collected, and genetically modified ex vivo using the lentiviral vector (Lenti-HBA) to restore α-globin expression, then reinfused following busulfan conditioning. The patient achieved engraftment within three weeks and started to be free of transfusions from the fourth week onward. In the last year of follow-up (M12-M24), the average hemoglobin level remained around 90 g/L without transfusion support, with HbA accounting for >85% of total hemoglobin. Vector copy numbers were stable, and no evidence of clonal dominance, insertional mutagenesis, or replication-competent lentivirus was detected. Adverse events were limited to expected busulfan-related toxicities, including Grade 2 menstrual irregularity and ovarian failure (SAE). Despite cessation of chelation therapy, iron overload progressed minimally and no cardiac iron deposition occurred. Immune recovery, growth and development were preserved. This case demonstrates the feasibility, safety, and durable efficacy of lentiviral α-globin gene therapy as a potential curative treatment for transfusion-dependent α-thalassemia. This trial was registered at www.clinicaltrials.gov as #NCT05851105.
Yin et al. (Wed,) studied this question.