Bluebird bio said Monday it has submitted its lovo-cel gene therapy for sickle cell disease for Food and Drug Administration approval, ending a brief delay as it awaited feedback from the agency on manufacturing.

The Massachusetts-based drugmaker missed its goal to submit an application by the end of March, allowing Vertex Pharmaceuticals and CRISPR Therapeutics to jump ahead with an approval application for a competing therapy.

The agency now has until late June to decide whether to accept Bluebird’s application. The company is seeking a “priority,” or expedited, review, which if granted would shorten the review from 10 months to six. Bluebird is planning for an expedited review and, should an approval be granted, an early 2024 commercial launch.

Lovo-cel is viewed by analysts as Bluebird’s best chance for business success because many more people in the U.S. have sickle cell disease than the rarer conditions treated by the company’s two approved gene therapies Zynteglo and Skysona.

An estimated 100,000 people live with sickle cell disease in the U.S., and about half do not live past the age of 40, according to Bluebird. Its treatment could provide long-lasting benefits by modifying a patient’s own stem cells.

Lovo-cel uses a lentivirus to insert functional versions of a gene that encodes for beta globin, part of the oxygen-carrying protein hemoglobin. When reintroduced in a patient, the modified cells produce an anti-sickling hemoglobin that crowds out the sticky, crescent-shaped hemoglobin that are characteristic of sickle cell. In clinical trials, the therapy increased total hemoglobin and eliminated the severe pain crises people with the disease often experience.

Like other gene therapies, safety concerns have slowed its development — nearly a decade for lovo-cel — and most recently led to a hold on a study in children and adolescents that was lifted in December.

Bluebird’s application puts it three weeks behind Vertex and CRISPR, which submitted their medicine exa-cel for approval in sickle cell disease and another rare blood disorder, beta thalassemia.

The two companies’ treatment also modifies a patient’s extracted stem cells, but uses CRISPR to edit a gene which suppresses a fetal form of hemoglobin.

Jack Allen, an analyst with Baird, wrote in a note to clients Monday that Bluebird’s submission keeps its timeline “as highly similar” with its competitors. First-to-market status is important for these kinds of treatments, he wrote, “as patients will only receive a single treatment and there will be no switching as is seen in chronic treatments.”

While Bluebird is slightly behind, Allen noted that its prior launch of two gene therapies could give it an advantage down the road.

Bluebird shares traded lower by about 3% in Monday morning trading.

Reference：

https://www.biopharmadive.com/news/bluebird-sickle-cell-fda-application-submit-gene-therapy/648395/