FDA Approves Bluebird Gene Therapy Zynteglo

On August 17, 2022, the U.S. FDA announced that it has approved the gene therapy Zynteglo (betibeglogene autotemcel, beti-cel) developed by bluebird bio for the treatment of beta thalassemia patients who require routine red blood cell transfusions. The release notes that this is the first FDA-approved gene therapy for this patient population.


Bluebird also received a priority review ticket.

Zynteglo is a one-time gene therapy. It genetically engineered hematopoietic stem cells isolated from patients in vitro so that they could produce functioning beta globin. After these hematopoietic stem cells are infused back into the patient, they will continuously generate red blood cells with normal functions, which greatly reduces the patient's need for blood transfusion. Ideally, patients don't even need blood transfusions. The therapy has previously been approved in the European Union.

The efficacy and safety of Zynteglo are supported by two multicenter clinical studies. Participants included adults and children with beta thalassemia who required routine red blood cell transfusions. Efficacy was assessed by transfusion independence, which was defined as a patient maintaining a predetermined hemoglobin level for at least 12 months without receiving red blood cell transfusions. Of the 41 patients treated with Zynteglo, 89% achieved transfusion independence. The latest follow-up results showed that this effect showed good durability.

Bluebird priced Zynteglo at $2.8 million, making it the most expensive drug. This pricing is based on clinical value. After Zynteglo treatment, most patients can get rid of blood transfusion dependence, and their hemoglobin levels can reach or approach normal levels.