FDA Lifts Clinical Hold on Studies of Sickle Cell Disease and Beta-Thalassemia Gene Therapies

June 09, 2021

The Food and Drug Administration lifted the clinical holds on the Phase 1/2 and Phase 3 trials of the betibeglogene autotemcel gene therapy for sickle cell disease (LentiGlobin) and on two Phase 3 trials of the betibeglogene autotemcel gene therapy for transfusion-dependent beta-thalassemia (beti-cel), manufacturer bluebird bio announced Monday. 

The company temporarily suspended the trials in March following a case of acute myeloid leukemia (AML) and a suspected case of myelodysplastic syndrome (MDS) among two patients who received LentiGlobin. There were no reports of hematologic malignancies among patients who received beti-cel (which is marketed as Zynteglo in the United Kingdom and European Union), but the company suspended the trials while assessing the AML case because beti-cel is manufactured using the same BB305 lentiviral vector as Lentiglobin.

Following an investigation, researchers at bluebird bio determined that it was “very unlikely” that the AML case reported in the LentiGlobin study was related to the BB305 lentiviral vector. Additionally, the treating investigator for the patient with the suspected case of MDS revised the patient’s diagnosis to transfusion-dependent anemia. 

The company is working closely with study investigators and clinical trial sites to resume all study activities as soon as possible. Additionally, the company is conducting long-term safety and efficacy follow-up studies for people who have participated in clinical studies of Lentiglobin or beti-cel.