Spruce Biosciences advances toward Q4 FDA filing for ultra-rare Sanfilippo B therapy

Spruce Biosciences reported progress toward filing its enzyme replacement therapy, tralesinidase alfa (TA-ERT), for Sanfilippo syndrome type B, an ultra-rare lysosomal disorder.

The company said two recent meetings with the FDA confirmed that its analytical comparability data for drug substance and product were acceptable, clearing a key regulatory hurdle that had delayed the filing from Q1 to Q4 2026.

The update follows Spruce’s transfer of manufacturing to a leading global biologics contract manufacturer and reflects continued momentum after acquiring the asset from BioMarin in 2019.

Investors see the regulatory advance as a positive step toward a potential approval, though the filing is still several months away.