Spruce Biosciences has put out new shoots, snapping up rights to a former BioMarin rare disease candidate and outlining plans to seek accelerated FDA approval in the first half of next year.
The deal gives Spruce global rights to tralesinidase alfa, an enzyme replacement therapy for use in the rare genetic disease Sanfilippo syndrome type B. Allievex licensed the program from BioMarin in 2019 but terminated (PDF) its operations in 2023 after failing to reach alignment with the FDA. According to Allievex, the agency changed its tune in March 2024 and encouraged its former staffers to seek approval.
Allievex lacked the resources to pursue the accelerated approval but, as part of the biotech’s liquidation, Spruce stepped up to take the asset forward. Spruce, which began looking for strategic alternatives last year, has assumed Allievex’s obligations to pay BioMarin up to $122.5 million in milestone fees, including $22.5 million in development and regulatory paydays.
In return, Spruce has secured the chance to seek accelerated approval on the strength of existing data, potentially netting a priority review voucher in the process. Asked by analysts why he is confident there is a path to accelerated approval, Spruce CEO Javier Szwarcberg, M.D., pointed to the agency’s acceptance of applications based on the same surrogate endpoint, change in heparan sulfate, in related conditions.
The FDA is set to rule on Ultragenyx’s gene therapy filing for Sanfilippo syndrome type A by August, while Denali Therapeutics began a rolling submission for its own candidate this month. Although those filings cover other forms of mucopolysaccharidosis than Sanfilippo syndrome type B, Szwarcberg argued they set a precedent.
“The FDA is honoring their prior commitments,” Szwarcberg said on a call with investors Tuesday. “We have not re-engaged with the FDA since we acquired the asset. Our review division is CDER, [the] same group of FDA that's regulating the Denali filing. Ultragenyx is under CBER. We have no reason to believe that the FDA will not honor the prior agreements made with the prior sponsor.”
Allievex founder Thomas Mathers, writing after reaching alignment with the FDA, predicted $60 million to $75 million of new investment was needed to allow for a submission and review of the candidate via the accelerated approval pathway. Mathers said at the time that the spending was needed to support manufacturing and the start of a confirmatory clinical trial.
Spruce ended last year with $38.8 million in cash and cash equivalents, a sum it said will fund operations through this year. Samir Gharib, Spruce’s chief financial officer, acknowledged on today's call with investors that the biotech faces a “very volatile market.” But Gharib framed this as a positive for the company, arguing that the asset is derisked and fits the profile investors are looking for.