Spruce Biosciences Presents Positive Data on Tralesinidase Alfa for MPS IIIB at WORLDSymposium

Long-term enzyme replacement therapy shows profound and durable reduction of heparan sulfate and stabilization of cognitive function and cortical gray matter volume

Published on Feb. 5, 2026

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Spruce Biosciences presented positive results from its studies on tralesinidase alfa, an enzyme replacement therapy for the treatment of Mucopolysaccharidosis (MPS) IIIB, at the 22nd Annual WORLDSymposium. The data showed that long-term administration of tralesinidase alfa resulted in a profound and durable reduction of heparan sulfate (HS) and stabilization of cognitive function and cortical gray matter volume (CGMV) in patients with MPS IIIB.

Why it matters

MPS IIIB is a rare, serious, and fatal progressive neurodegenerative disease with no approved treatment options currently available. The positive results from Spruce Biosciences' studies on tralesinidase alfa demonstrate the potential of this therapy to address the unmet medical need for MPS IIIB patients by stabilizing cognitive and non-cognitive outcomes and reducing the accumulation of harmful HS.

The details

The studies evaluated the long-term safety and efficacy of weekly intracerebroventricular (ICV) administration of 300 mg tralesinidase alfa in patients with MPS IIIB. The data showed that tralesinidase alfa rapidly normalized cerebrospinal fluid (CSF) HS and HS-nonreducing end (HS-NRE) levels, stabilized cortical gray matter volume, and preserved cognitive, communication, and motor skills compared to untreated patients. The safety profile was consistent with that expected for an ICV-administered drug, with no severe or serious hypersensitivity-related adverse events.

  • The 22nd Annual WORLDSymposium was held on February 2-6, 2026 in San Diego, CA.

The players

Spruce Biosciences

A biopharmaceutical company developing tralesinidase alfa, an enzyme replacement therapy for the treatment of Mucopolysaccharidosis (MPS) IIIB.

Nicole Muschol

A researcher at the University Medical Center Hamburg-Eppendorf's International Center for Lysosomal Disorders and the presenting author of the study.

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What they’re saying

“We sincerely thank the participants, their family members, and caregivers for their participation in the studies.”

— Nicole Muschol, Researcher (Internal data)

“We would also like to thank all the investigators, study staff, and personnel for their contributions.”

— Nicole Muschol, Researcher (Internal data)

What’s next

Spruce Biosciences plans to initiate a Phase 3 confirmatory trial of tralesinidase alfa for the treatment of MPS IIIB.

The takeaway

The positive results from Spruce Biosciences' studies on tralesinidase alfa demonstrate the potential of this enzyme replacement therapy to address the significant unmet medical need for MPS IIIB patients by stabilizing cognitive and non-cognitive outcomes and reducing the accumulation of harmful heparan sulfate.