BioCryst leaves ultra-rare bone disease efforts in hands of Ipsen, Regeneron with discontinuation

With compliments to its peer drugmakers developing other oral ALK-2 inhibitors, BioCryst is stepping back from the effort to produce a therapy for an ultra-rare bone disease—and keeping $100 million in its pocket for other priorities.

BioCryst is shutting down its BCX9250 program for fibrodysplasia ossificans progressiva (FOP), a rare genetic disease that causes soft tissue to permanently turn into bone. The company is bowing out after collecting some preclinical data that suggested the therapy could reduce excess bone formation.

“The company believes that patients with FOP, an ultra-rare disease, are likely to benefit from other oral ALK-2 inhibitors that currently are substantially ahead of BCX9250 in development,” the biotech said in a third-quarter earnings report issued Tuesday morning.

Stepping away now will leave the Durham, North Carolina-based company with $100 million to redirect towards its efforts in complement-mediated diseases. That’s how much cash BioCryst says would have been required to bring BCX9250 to approval.

It’s a quick turnaround for BCX9250, which was just granted an orphan drug designation by the FDA in August and a fast-track designation a few months before. The therapy has already been scrubbed from BioCryst’s webpages and pipeline. At the time of the orphan tag announcement, BioCryst declared its commitment to “bringing this important oral investigational therapy to FOP patients.”

But now, the company seems to think that work is better left to its peers who are further ahead. BioCryst did not name names, but a few companies have therapies in development for FOP. The leader is Ipsen, which has faced a rocky road to get palovarotene past U.S. regulators. A week ago, Ipsen announced that a planned FDA advisory meeting to discuss the drug was off, pushed back until the company can provide additional clinical trial data.

The therapy was previously subject to an FDA clinical hold in pediatric patients placed in December 2019. Then, Ipsen paused dosing in a phase 3 study that included adults due to interim data that showed the trial was unlikely to meet its primary endpoint. Ipsen did not cancel the study altogether though, continuing on with the blessing of the independent review board because “encouraging therapeutic activity” was observed.

That study was ultimately used to file for FDA approval, which was later retracted. But palovarotene did get the blessing of Canadian regulators in January for use in adults and children 8 years or older for girls and 10 years or older for boys. The FDA application was resubmitted in June.

So while BioCryst is passing the torch, U.S. patients still may have a lengthy wait on their hands as the regulatory kinks are worked out with Ipsen’s application.

Regeneron is also working through a late-stage study in FOP with garetosmab, which has faced significant hurdles in the clinic. A phase 2 trial was halted in late 2020 after multiple patients died during an extension portion of the study. According to Regeneron’s second quarter (PDF) earnings report from August, garetosmab is slated for an FDA submission in 2024 or beyond.

BioCryst will instead turn its attention to its complement-mediated diseases pipeline, including the factor D inhibitors BCX9930 and BCX10013. BCX9930 is furthest in the clinic, having recently overcome a partial clinical hold thanks to a revised protocol that brought down dosing. BioCryst is advancing the med in patients with paroxysmal nocturnal hemoglobinuria, C3 glomerulopathy, immunoglobulin A nephropathy and primary membranous nephropathy.