Bluebird Bio is a developer of gene therapies for severe genetic diseases. It works on ZYNTEGLO (betibeglogene autotemcel) program, gene therapy for people with β-thalassemia who require regular red blood cell transfusions, and SKYSONA (elivaldogene autotemcel) program, therapy that slows the progression of neurologic dysfunction in children with cerebral adrenoleukodystrophy. The company also develops lovotibeglogene autotemcel (lovo-cel) as a one-time treatment for patients with sickle cell disease.