bluebird bio’s beta-thalassaemia gene therapy receives FDA approval

blubird bio’s Zynteglo (betibeglogene autotemcel) – also known as beti-cel – has been approved by the US Food and Drug Administration (FDA) for patients with beta-thalassaemia (beta-thal) in adult and paediatric patients who require regular red blood cell transfusions.

Beta-thal is a rare genetic blood disease caused by a gene defect that impairs the ability of red blood cells to produce haemoglobin. Patients with the most severe form of beta-thal develop life-threatening anaemia and have to undergo regular blood transfusions, a lengthy process typically needed every two to five weeks.

Transfusions are only a temporary solution to symptoms of anaemia and those with beta-thal who require regular transfusions have an increased risk of mortality due to treatment and disease-related iron overload.

Zynteglo works by adding functional copies of a modified form of the beta-globin gene into a patient’s own haematopoietic stem cells to allow them to make normal to near normal levels of total haemoglobin without regular red blood cell transfusions. The functional beta-globin gene is added into a patient’s cells outside of the body, and is then infused into the patient.

The FDA’s decision is based on data from the company's phase 3 studies HGB-207 (Northstar-2) and HGB-212 (Northstar-3), and the long-term follow-up study LTF-303.

The single-arm, open-label, 24-month phase 3 studies saw 32 out of 36 evaluable patients achieve transfusion independence, defined as no longer needing red blood cell transfusions for at least 12 months while maintaining a weighted average total haemoglobin of at least 9g/dL.

Across all studies, all patients who achieved transfusion independence have remained transfusion-free, the company noted.

Due to the complex nature of gene therapy, Zynteglo will be available exclusively at qualified treatment centres, selected based on expertise in relevant areas such as stem cell transplantation, cell and gene therapy, and beta-thal.

Commenting on the approval, Andrew Obenshain, chief executive officer, bluebird bio, said: “The FDA approval of Zynteglo offers people with beta-thal the possibility of freedom from burdensome regular red blood cell transfusions and iron chelation, and unlocks new possibilities in their daily lives.

“After more than a decade of research and clinical development, and through the perseverance of clinicians, patients, and their families, the approval of Zynteglo marks a watershed moment for the field of gene therapy.”