Bluebird hit with another FDA hold on sickle cell gene therapy

Dec. 20, 2021

Bluebird bio announced that the U.S. FDA has placed its clinical program for lovotibeglogene autotemcel (lovo-cel) gene therapy for sickle cell disease on partial clinical hold for patients under the age of 18.

The partial, temporary suspension relates to an ongoing investigation by bluebird into an adolescent patient with persistent, non-transfusion-dependent anemia following treatment with lovo-cel, now 18 months post-treatment. The drugmaker notes that the patient is clinically well and there is no evidence of malignancy or clonal predominance.

Lovo-cel gene therapy, also known as LentiGlobin, is an investigational one-time treatment being studied for sickle cell disease that is designed to add functional copies of a modified form of the β-globin gene into a patient’s own blood stem cells.

But this isn’t the first time that bluebird has grappled with unexpected side effects during a trial involving lovo-cel. Earlier this year, a trial for the treatment was placed on a clinical hold due to safety concerns. The hold was lifted in June, but the delay was enough to push the company’s plan to file for an approval for the treatment back to 2022 and then last month, bluebird pushed back the filing again, this time to the first quarter of 2023.

Now, the Cambridge, MA-based gene therapy maker has paused enrollment and treatment of patients younger than 18 in its sickle cell clinical program. Bluebird anticipates receiving written questions from the agency in early 2022 and says it will work quickly to respond in order to resolve the partial hold.