Abstract
This is a multi-center, long-term safety and efficacy follow-up study for subjects with
transfusion-dependent β-thalassemia (TDT) who have been treated with ex vivo gene therapy
drug product in bluebird bio-sponsored clinical studies. After completing the parent clinical
study (approximately 2 years), eligible subjects will be followed for an additional 13 years
for a total of 15 years post-drug product infusion. No investigational drug product will be
administered in the study.
