FDA accepts bluebird bio sickle cell gene therapy BLA

June 22, 2023

Massachusetts-based biotech bluebird bio announced this week that the FDA had accepted the Biologics License Application for its sickle cell gene therapy, lovo-cel, with priority review.

The drug, a one-time treatment designed to introduce a functional copy of the gene that enables the production of adult hemoglobin, now has a PDUFA goal date of December 20, 2023. 

The BLA has been a hard-fought battle for bluebird, having had to repeatedly push back its filing. In early 2021,a lovo-cel trial was placed on a clinical hold due to safety concerns. Later that year, the FDA put a partial clinical hold on the lovo-cel program for patients under the age of 18 while bluebird investigated an adolescent patient with persistent, non-transfusion-dependent anemia following treatment.

bluebird had set a Q1 2023 BLA submission goal for lovo-cel, but after the drugmaker had to refine manufacturing processes for the drug, the FDA asked for comparability data from its CMC practices — delaying the BLA submission until late April.  

The BLA was supported with efficacy data from 36 patients in the HGB-206 study Group C cohort with a median 32 months of follow-up, as well as two patients in the HGB-210 study with 18 months of follow-up each. The company also provided safety data from 50 patients treated across the entire lovo-cel program, including six patients with six or more years of follow-up, which marks the longest follow-up period among all gene therapy programs for SCD.

Sickle cell disease is a progressive genetic condition characterized by debilitating pain crises, organ damage, and premature death. Despite being the first genetically identified disease, treatment advances have been limited, with only four approved therapies that do not target the underlying genetic cause.

If approved, lovo-cel would become bluebird bio's third ex-vivo gene therapy to receive FDA approval for a rare genetic disease and its second FDA approval for an inherited hemoglobin disorder.

Besides Priority Review, lovo-cel has received Orphan Drug, Fast Track, Regenerative Medicine Advanced Therapy and Rare Pediatric Disease designations from the FDA.