CRISPR-Cas12a Gene Editing of HBG1 and HBG2 Promoters to Treat β-Thalassemia

promoters to reactivate fetal hemoglobin production for the treatment of transfusion-dependent β-thalassemia.

We conducted a phase 1-2, multicenter, open-label, single-group study of reni-cel in participants 18 to 35 years of age with transfusion-dependent β-thalassemia. The participants received myeloablative conditioning with busulfan before reni-cel infusion. The primary end points were neutrophil engraftment by 42 days after infusion and frequency and severity of adverse events. Participants were monitored for hemoglobin-related measures and transfusion independence. The study was terminated early on the basis of the sponsor's reassessment of clinical development priorities. Results of an analysis that was not prespecified are reported.