Bluebird gene therapy overcomes safety worries to snag a win at FDA advisory panel

After facing serious safety doubts from FDA reviewers on its gene therapy prospect eli-cel, bluebird bio has convinced an expert panel that the drug's benefits outweigh its risks—at least in some patients.

In the first day of a high-stakes, two-day meeting centered on two of the company's gene therapy applications, the FDA asked its Cellular, Tissue, and Gene Therapies Advisory Committee to hear evidence and weigh the risks and benefits of elivaldogene autotemcel. The bluebird bio gene therapy is under review to treat cerebral adrenoleukodystrophy (CALD) patients under 18.

After hearing hours of evidence on the drug's efficacy and safety, the panel voted 15-0 that the benefits of eli-cel outweigh the risks for certain groups of CALD patients.

Several panelists said they thought the drug is appropriate for patients who don't have a matched stem cell donor. For those with a donor, that "could be left up to the clinician and patient's discretion," said Donna Roberts, M.D., professor in the department of radiology and radiological sciences at the Medical University of South Carolina.

"Overall, I think this a very important product to have on the market," she said.

The panel gave its recommendation despite hearing detailed safety concerns from the FDA's staffers. In briefing documents ahead of the meeting, FDA staff flagged the risk of myelodysplastic syndrome (MDS), a type of cancer that emerged in 3 of 67 patients (4%) treated with the therapy. 

At the meeting, Leah Crisafi, M.D., a clinical reviewer at the FDA's Office of Tissues and Advanced Therapies, said there’s a “significant risk of malignancy with eli-cel administration.” 

The current incidence is 4%, she noted, but is “likely to increase” because the duration of follow-up during the drug’s clinical testing was “relatively brief” and “may have been insufficient for malignancy to have occurred.”  

Still, the committee vote puts the drug on solid ground ahead of its September 16 decision deadline at the FDA. The agency doesn’t always follow its advisory committee votes, but it typically does. 

Last summer, the drug won approval in Europe under the brand name Skysona.

For bluebird, the vote brings a needed win after a series of setbacks over the last couple of years. After winning approval for betibeglogene autotemcel to treat beta thalassemia in Europe in June 2019, the company was forced to pull out of the market last year after it couldn’t convince payers of its expensive therapy's value. 

In April, the company cut 30% of its staff after its marketing hopes in Europe were dashed and regulatory delays loomeds in the U.S.

The company’s beti-cel FDA advisory committee review is set for Friday.