ASH Report: Pediatric Results in bluebird bio Gene Therapy Trial
December 6, 2020 – Initial results from Phase 3 clinical trials showed that 10/12 adult patients with transfusion-dependent beta thalassemia achieved transfusion independence following treatment with bluebird bio’s beti-cel (LentiGlobin) gene therapy for β-thalassemia. After showing initial success in adult patients, these trials were expanded to include adolescents and children. Preliminary findings from the pediatric trials of beti-cel in beta thalassemia were presented by Dr. Alexis Thompson of the Ann & Robert H. Lurie Children’s Hospital of Chicago, IL at the 2020 American Society of Hematology (ASH) annual meeting.
24 pediatric patients, ranging from 4 to 17 years of age, were treated with beti-cel gene therapy. 14 of these patients were enrolled in the study of beti-cel in patients with non-B0/B0 genotypes. Of these, 10 patients were ready for evaluation at the time the analysis was performed. Transfusion independence is defined as a weighted average hemoglobin ≥9 g/dL without transfusions for at least 1 year. In this dataset, transfusion independence was achieved in 3/4 (75% of) patients under 12 years of age, with a weighted average hemoglobin of 10.0 g/dL. In contrast, 6/6 (100% of) patients ages ≥12 to <18 years of age achieved transfusion independence, with a weighted average hemoglobin of 11.6 g/dL.
10 pediatric patients were enrolled in the study of beti-cel in patients with the more severe B0/B0, B0/B+IVS-1-110, or B+IVS-1-110/ B+IVS-1-110 genotypes. Of these, 5 patients were ready for evaluation at the time the analysis was performed. In this dataset, transfusion independence was achieved in 1/2 (50% of) patients under 12 years of age, with a weighted average hemoglobin of 10.3 g/dL. In contrast, 3/3 (100% of) patients ages ≥12 to <18 years of age achieved transfusion independence, with a weighted average hemoglobin of 9.6 g/dL.
Grade 4 veno-occlusive disease occurred in 2 patients and grade 2 veno-occlusive disease occurred in 1 patient; all cases were successfully treated with defibrotide. The safety profile of gene therapy with beti-cel in this pediatric population was consistent with the side effects typically observed with busulfan conditioning.
Preliminary findings from these studies indicate that pediatric patients < 18 years of age achieved transfusion independence at comparable rates to adult patients, suggesting that beti-cel gene therapy represents an effective treatment option across age groups for patients with transfusion-dependent beta thalassemia.
Further information about these pediatric trials can be found in the ASH meeting abstract at: https://ash.confex.com/ash/2020/webprogram/Paper135857.html