FDA Approves First Gene Therapy for Beta-thalassemia

The FDA Wednesday approved betibeglogene autotemcel (Zynteglo), the first cell-based gene therapy for the treatment of adult and pediatric patients with beta-thalassemia who require regular red blood cell transfusions.

Betibeglogene autotemcel is a 1-time gene therapy product administered as a single dose; each dose is customized using the patient’s own bone marrow stem cells that are genetically modified to produce functional beta-globin.

The approval was granted to bluebird bio, Inc. In May, the Institute for Clinical and Economic Review (ICER), an independent cost-effectiveness group, issued a favorable review of Zynteglo, giving the treatment a B+ rating and said the anticipated price of $2.1 million met ICER’s health benefit benchmarks with an 80% payback option for patients who are not cured and continue to need transfusions.

The safety and effectiveness of betibeglogene autotemcel were established in 2 multicenter clinical studies. Effectiveness was established based on achievement of transfusion independence, which is attained when the patient maintains a predetermined level of hemoglobin without needing any red blood cell transfusions for at least 12 months. Of 41 patients receiving Zynteglo, 89% achieved transfusion independence.

Beta-thalassemia is a type of inherited blood disorder that causes a reduction of normal hemoglobin and red blood cells in the blood, through mutations in the beta-globin subunit, leading to insufficient delivery of oxygen in the body.

The reduced levels of red blood cells can lead to a number of health issues including dizziness, weakness, fatigue, bone abnormalities and more serious complications.

Transfusion-dependent beta-thalassemia, the most severe form of the condition, generally requires lifelong red blood cell transfusions as the standard course of treatment. These regular transfusions can be linked with multiple health complications of their own, including problems in the heart, liver, and other organs due to an excessive buildup of iron in the body.

Although it is a 1-time treatment, bluebird bio said in a statement that due to the multiple steps involved, the entire process of treating a patient may take several months.

The application was granted a rare pediatric disease voucher, in addition to receiving priority review, fast track, breakthrough therapy, and orphan drug designations.