Bluebird’s gene therapy for brain disease receives accelerated approval

Bluebird Bio’s shares gained in premarket trading on Monday (Sep 19) after its gene therapy for a brain-wasting disease received accelerated approval from US regulators, making it the first treatment of its kind for children living with cerebral adrenoleukodystrophy.

The 1-time treatment will be sold under the name Skysona and cost US$3 million, chief executive officer Andrew Obenshain said in an interview. That price is a record in the US. The approval allows Somerville, Massachusetts-based Bluebird to introduce its gene therapy under the condition it provides long-term data to prove the treatment’s benefit, according to a company statement.

The shares rose 6.8 per cent as of 7:29 am in New York. They’d lost more than a third of their value this year through Friday’s close.

Bluebird’s therapy, also known as eli-cel, treats cerebral adrenoleukodystrophy, or CALD, a rare genetic condition that afflicts young boys and can cause rapid deterioration and death. Until now, the only treatment available for this condition was a stem-cell transplant from a sibling or a matched donor.

With 70 per cent of patients diagnosed with CALD not having a matching donor, eli-cel could significantly improve the lives of such patients. The therapy was approved for boys between the ages of 4 and 17 regardless of whether they have a match.

The company had sought a full approval of the treatment, but it became clear in conversations with regulators the accelerated pathway was the best option, Obenshain told Bloomberg on Friday. While data from a late-stage trial showed promising results in the treatment’s efficacy, at least 3 patients who received eli-cel developed cancer of the bone marrow. Trials were paused in August 2021 because of safety concerns. The hold will lift in conjunction with the approval.

In June, a panel of expert advisers to the FDA unanimously voted in favour of the treatment, saying the benefits outweighed the risks. However, the panel stressed the need for aggressive monitoring of patients after they are treated.

Skysona’s clearance marks Bluebird’s second approval within a month, infusing fresh hope into a company that recently warned it might run out of money. Bluebird plans to sell priority review vouchers it received from the FDA upon the 2 approvals, which it estimates could fetch around US$110 million each.

With only about 40 patients diagnosed with CALD each year, Skysona represents Bluebird’s smallest opportunity. In comparison, the company estimates more than 850 people could be eligible to receive its Zynteglo gene therapy for blood disorder beta thalassemia.

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“This has always been about the boys and less about the commercial opportunity for us and much more about the realisation of the mission,” Obenshain said.

Sickle cell disease, another blood disease, is Bluebird’s biggest potential market, with more than 20,000 people who could be eligible for gene therapy, according to company estimates. Its management plans to file an application for the treatment with US regulators early next year. BLOOMBERG