Bluebird touts Zynteglo, Skysona launch progress as FDA decision on sickle cell therapy nears

After closing shop in Europe two years ago, bluebird bio still aims to become an industry-leading gene therapy maker in the U.S. But first, it’s hoping new launches will help keep its doors open over the next 12 months.

Since their approvals last year, bluebird’s Zynteglo has so far signed on 11 beta-thalassemia patients and Skysona five patients in the rare brain disease cerebral adrenoleukodystrophy, the company said Tuesday. The gene therapies scored successive FDA approvals last August and September, respectively.

For Zynteglo, it takes an average 70 days to 90 days to manufacture, test, release and then deliver the therapy back to the hospital, and the actual infusion comes later, bluebird’s commercial chief Tom Klima told investors on a call Tuesday.

Assuming all those patient starts result in infusions, that means the company is due for about $45 million in revenues over time, bluebird CEO Andrew Obenshain said on the call. For the second quarter, bluebird booked $6.8 million in product revenues.

Those revenues, plus a closely-watched FDA decision on sickle cell disease candidate lovo-cel by the end of the year, will be key to bluebird’s survival in the next year or so.

Since bluebird launched a comprehensive restructuring last spring, the Massachusetts company has been warning of “substantial doubt” that it may not survive in the near term. The company currently expects its cash runway to extend into late 2024, or the second quarter next year after removing some restricted cash that’s currently not available for use.

Two years ago, bluebird halted its European operations because of unfavorable pricing dynamics in the region. In the U.S., for now, no commercial or government payers have denied coverage for either Zynteglo or Skysona, Obenshain said.

Zynteglo’s launch is progressing about as expected, Klima said, describing a gradual and linear uptake trajectory. Bluebird aims to activate around 40 to 50 treatment centers for Zynteglo by the end of the year, he said.

As for Skysona, the therapy is less important to bluebird given the rarity of the disease. Skysona carries a boxed warning about blood malignancy, including the life-threatening condition of myelodysplastic syndrome (MDS), which appears to be caused by the lentiviral vector used to deliver the gene therapy.

In July, two more patients from Skysona’s clinical trial experienced MDS, bringing the total number so far to five cases, Klima said. The company expects more cases in the future given the known risk, he added.

“Nevertheless, we continue to believe that Skysona remains an important therapy for patients who have no other treatment options,” Klima said.

Importantly, Zynteglo and its sister med lovo-cel use a different vector from Skysona’s based on the cell type they target, and their vector has a different safety profile.

“This is well understood by clinicians and the FDA as well,” Klima said.

Lovo-cel targets a much larger patient population than bluebird’s two approved gene therapies. It’s also expected to go head-to-head with Vertex and CRISPR Therapeutics’ CRISPR-based exa-cel in SCD.

Bluebird’s market research shows that more than 70% of patients will make treatment decisions based on efficacy and long-term follow-up data, instead of the therapy’s modality, Klima said, touting lovo-cel’s efficacy and safety profile.

Like with its existing gene therapies, bluebird has already worked out outcomes-based reimbursement agreements around lovo-cel with payers, the chief commercial officer said.