Data Highlight TA-ERT's Potential as the First Disease-Modifying Treatment Option for MPS IIIB, a Fatal Condition With No Approved Therapies

Treatment With Weekly TA-ERT Demonstrated Rapid and Durable Normalization of CSF Heparan Sulfate Non-Reducing End (CSF HS-NRE), a Surrogate Endpoint Reasonably Likely to Predict Clinical Benefit

TA-ERT Stabilized and Preserved Cognitive and Non-Cognitive Outcomes, Including Communication and Motor Skills, Over a Six-Year Period Relative to Natural History Patients

Spruce Biosciences, Inc. (NASDAQ:SPRB), a late-stage biopharmaceutical company focused on developing and commercializing novel therapies for neurological disorders with significant unmet medical need, today announced that data demonstrating the long-term benefit of tralesinidase alfa enzyme replacement therapy (TA-ERT) in patients with Sanfilippo Syndrome Type B (MPS IIIB) were presented at the 18th International MPS & Related Lysosomal Diseases Symposium, which took place June 4-7, 2026 in Florence, Italy. The data show that long-term administration of TA-ERT resulted in rapid and durable reduction of heparan sulfate and preserved cognitive and non-cognitive outcomes relative to natural history patients.

The presentation, which includes data previously presented at the 22nd Annual WORLDSymposium™, was delivered by Nicole Muschol, M.D., of the International Center for Lysosomal Disorders (ICLD) at the University Medical Center Hamburg-Eppendorf in Germany and Principal Investigator for the TA-ERT clinical development program.