The FDA has lifted clinical holds on four studies from Bluebird Bio Inc., following recent similar actions with other gene therapy programs. Two of the studies concern phase I/II and phase III clinical trials of the gene therapy Lentiglobin (BB-1111) in treating sickle cell disease. The remaining two studies are phase III clinical trials of betibeglogene autotemcel gene therapy, which share a vector with Lentiglobin, for treating transfusion-dependent beta-thalassemia.