Busulfan-Induced Infertility May Deter Some Pediatric Patients From Bluebird, Other Gene Therapies

Less than a week after the American Society of Hematology meeting ended on 13 December, the US Food and Drug Administration has provided relief to bluebird bio’s sickle cell disease (SCD) candidate lovotibeglogene autotemcel (lovo-cel) as it has lifted the partial clinical hold on a trial of the company’s gene therapy that prevented it from enrolling patients under 18. But experts at the meeting said a long-term side effect of the conditioning regimen used for lovo-cel as well as bluebird’s Zynteglo (betibeglogene autotemcel) may hamper its future uptake, particularly among younger patients.

Somerville, MA-based bluebird said on 19 December that the FDA had lifted the partial hold for patients younger than 18 in studies evaluating lovo-cel in SCD. The hold was placed in December 2021 after an adolescent patient in one of the trials developed persistent, non-transfusion-dependent anemia following treatment with the gene therapy