Medicine: Stem cell transplants effective as treatment for β-thalassaemia (Nature)

Stem cell transplantation could be a rapid and effective way to restore haemoglobin production in individuals with the blood disorder β-thalassaemia, reports a study in Nature. The treatment, presented in a phase 1 clinical trial, could reduce dependence on blood transfusions in some individuals with the disease in the future, although further trials are needed to confirm these findings.

β-Thalassaemia is a blood disease characterised by an inability to correctly synthesise the β-subunit of haemoglobin, which can lead to anaemia and defects in the production of red blood cells. The defective subunit synthesis can be caused by over 350 different known mutations in the β-globin gene (HBB) and is primarily treated by regular red blood cell transfusions, which can be arduous for patients. Fetal haemoglobin (HbF, which is expressed in fetuses but declines after birth) lacks a β-subunit; thus, increasing its levels may have potential as a long-term treatment for β-thalassaemia. Elevating HbF levels could be achieved through stem cell therapies; however, clinical trials to test this approach have been lacking.

Jia Chen and colleagues present the results of a phase 1 clinical trial, in which five patients with severe β-thalassaemia received a one-time infusion of their own modified stem cells. The authors used base editing to modify specific binding sites and reactivate the gene responsible for HbF production. The participants ceased regular red blood cell transfusions within one month after the stem cell infusion. Total haemoglobin and HbF concentrations of 12.4 and 11.5 grams per decilitre of blood were observed at three months post infusion, suggesting successful production of functional haemoglobin. These levels were sustained or improved upon throughout the follow-up period, which lasted for a median of 23 months.

Further clinical research will be needed to validate the results of this treatment in a larger cohort and over a longer period. However, these results suggest that a one-time stem cell infusion could assist some patients in regaining independence from reliance on transfusions.

• Article
• Published: 08 April 2026

Lai, Y., Liu, R., Wang, L. et al. Clinical application of base editing for treating β-thalassaemia. Nature (2026). https://doi.org/10.1038/s41586-026-10342-9

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