SPRUCE BIOSCIENCES, INC.

TA-ERT Program Updates

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Continued progress toward BLA submission for TA-ERT for the treatment of MPS IIIB: Spruce continues to advance manufacturing readiness, regulatory interactions, and commercial planning to support an anticipated BLA submission in the fourth quarter of 2026. There is currently no FDA-approved therapy for the treatment of MPS IIIB, and disease management consists of limited palliative care.

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Long-term TA-ERT data presented at the 22nd Annual WORLDSymposium™: At the February 2026 22nd Annual WORLDSymposium™, Spruce shared long-term clinical data supporting TA-ERT as a potential first disease-modifying treatment option for patients with MPS IIIB.

In a platform presentation on February 5, 2026, titled “Long-term administration of tralesinidase alfa enzyme replacement therapy (TA-ERT) results in profound and durable reduction of heparan sulfate (HS) and stabilization of cognitive function and cortical gray matter volume (CGMV) in patients with Sanfilippo Syndrome Type B (MPS IIIB),” Nicole Muschol, M.D., of the International Center for Lysosomal Disorders at the University Medical Center Hamburg-Eppendorf, presented data demonstrating that long-term administration of TA-ERT resulted in rapid and durable reductions in cerebrospinal fluid heparan sulfate, with stabilization of cognitive function and cortical gray matter volume relative to natural history.

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Confirmatory study and expanded access: Spruce continues to advance plans for a confirmatory study in patients with MPS IIIB and expanded access program to support continued patient access prior to and following potential approval.