Long-Term Data for bluebird bio’s betibeglogene autotemcel (beti-cel) Gene Therapy Show Patients Across Ages and β-thalassemia Genotypes Achieve Transfusion Independence and Remain Free from Transfusions Up to Six Years Presented at 62nd ASH Meeting

bluebird bio, Inc. (Nasdaq: BLUE) today presented updated long-term efficacy and safety results reflecting up to six years of data for betibeglogene autotemcel gene therapy (beti-cel; formerly LentiGlobin for β-thalassemia) in patients with transfusion-dependent β-thalassemia (TDT). The company also presented results for pediatric patients in the Phase 3 HGB-207 (Northstar-2) and HGB-212 (Northstar-3) studies. These data were presented at the 62^nd American Society of Hematology (ASH) Annual Meeting and Exposition, taking place virtually from December 5-8, 2020.

“Our vision for beti-cel gene therapy is that a one-time treatment would enable lifelong, stable production of functional hemoglobin at sufficient levels to allow patients with β-thalassemia to stop and remain free from blood transfusions,” said David Davidson, M.D., chief medical officer, bluebird bio. “All of the patients in our Phase 3 studies who achieved transfusion independence have maintained it, with the durability of the treatment effect underscored by patients from our earlier studies reaching their five-year anniversaries of freedom from transfusions. Moreover, transfusion independence has been observed in pediatric, adolescent and adult patients, and across genotypes – suggesting consistent outcomes with beti-cel regardless of age or genotype.”

TDT is a severe genetic disease caused by mutations in the β-globin gene that result in reduced or significantly reduced hemoglobin (Hb). In order to survive, people with TDT require chronic blood transfusions to maintain adequate Hb levels. These transfusions carry the risk of progressive multi-organ damage due to unavoidable iron overload.

Beti-cel is a one-time gene therapy that adds functional copies of a modified form of the β-globin gene (β^A-T87Q-globin gene) into a patient’s own hematopoietic (blood) stem cells (HSCs). Once a patient has the β^A-T87Q-globin gene, they have the potential to produce HbA^T87Q, which is gene therapy-derived adult Hb, at levels that may eliminate or significantly reduce the need for transfusions. In studies of beti-cel, transfusion independence (TI) is defined as no longer needing red blood cell transfusions for at least 12 months while maintaining a weighted average Hb of at least 9 g/dL.