Safety concerns halt gene therapy trial

Aug. 10, 2021

Bluebird bio announced this week that the FDA has slapped a clinical hold on the company’s trial for a gene therapy.

The company disclosed in an earnings statement that the hold relates to an unexpected case of myelodysplastic syndrome, a condition that stops blood-forming cells in bone marrow from maturing into healthy blood cells. According to the company, the patient who developed the condition took the company’s therapy — elivaldogene autotemcel (eli-cel) — in a phase 2 trial about a year ago to treat cerebral adrenoleukodystrophy (CALD).

The company said that evidence currently suggests that design features of the trial likely contributed to the case of myelodysplastic syndrome.

This isn’t the first time the company has grappled with unexpected side effects during a trial. The company’s treatment for sickle cell and β-thalassemia — LentiGlobin — was also placed on a clinical hold due to safety worries. The hold was later lifted but the company’s plan to file for an approval for the treatment has been pushed back to 2022.

Bluebird said this latest road bump will not impact progress on the development of its other gene therapies. 

Shares for the company were down 24% after news of the eli-cel hold.