Spruce Biosciences Acquires Former BioMarin Asset, Eyes 2026 FDA Approval

Spruce Biosciences has made a strategic move to bolster its pipeline, acquiring global rights to tralesinidase alfa, a former BioMarin rare disease candidate. The enzyme replacement therapy, targeted for use in Sanfilippo syndrome type B, is now slated for an accelerated FDA approval filing in the first half of 2026.

Deal Details and Financial Implications

The acquisition comes as part of Allievex's liquidation process, with Spruce assuming the biotech's obligations to BioMarin. This includes potential milestone payments of up to $122.5 million, with $22.5 million earmarked for development and regulatory achievements.

Spruce CEO Javier Szwarcberg, M.D., expressed confidence in the path to accelerated approval, citing the FDA's acceptance of applications based on the same surrogate endpoint—change in heparan sulfate—in related conditions. This move aligns with Spruce's search for strategic alternatives, initiated last year.

Regulatory Landscape and Industry Context

The FDA's regulatory environment for rare disease treatments appears to be evolving. In March 2024, the agency reportedly changed its stance and encouraged former Allievex staffers to seek approval for tralesinidase alfa. This shift comes amid a broader context of rare disease drug development:

• Ultragenyx's gene therapy for Sanfilippo syndrome type A is under FDA review, with a decision expected by August.
• Denali Therapeutics recently began a rolling submission for its own candidate in the mucopolysaccharidosis space.

Szwarcberg noted, "The FDA is honoring their prior commitments," emphasizing that Spruce's review division at the FDA (CDER) is the same group regulating Denali's filing.

Financial Considerations and Market Outlook

Spruce ended 2023 with $38.8 million in cash and cash equivalents, which the company states will fund operations through 2025. However, additional investment may be required to support manufacturing and initiate a confirmatory clinical trial. Former Allievex founder Thomas Mathers estimated that $60 million to $75 million in new investment would be needed for submission and review via the accelerated approval pathway.

Spruce's CFO, Samir Gharib, acknowledged the "very volatile market" but framed the acquisition as a positive move, arguing that the asset is derisked and aligns with investor preferences in the current climate.