This month, Spruce Biosciences shared long-term data from its tralesinidase alfa enzyme replacement therapy (TA-ERT), an investigational treatment for Sanfilippo Syndrome type B (MPS IIIB), at the 18th International MPS & Related Lysosomal Diseases Symposium, June 4-7, 2026, in Florence, Italy.
Spruce’s TA-ERT delivers replacement NAGLU directly into the central nervous system through intracerebroventricular administration. The therapy combines recombinant NAGLU (the deficient enzyme that causes Sanfilippo Type B) with an insulin-like growth factor 2 (IGF2) targeting component that enhances uptake into cells and delivery to lysosomes, where it can help clear the toxic heparan sulfate buildup that drives neurological decline.
At the Symposium, investigators presented six years of follow-up data from 22 children treated with TA-ERT. The results suggest that the therapy may be capable of modifying the course of disease rather than simply treating symptoms.
Researchers reported the following according to a press release by Spruce:
- Rapidly and durably normalized levels of cerebral spinal fluid heparan sulfate non-reducing end (CSF HS-NRE), a surrogate endpoint reasonably likely to predict clinical benefit in patients with MPS IIIB;
- Stabilized cognitive function, as assessed by the Bayley-III Cognitive Raw Score (BSID-C), the cognitive subscale of the validated Bayley Scales of Infant and Toddler Development – Third Edition (Bayley-III), relative to declines seen in untreated natural history patients;
- Stabilized receptive and expressive communication, as well as fine and gross motor skills, compared with a decline in these outcomes in untreated natural history patients, as assessed by the Vineland Adaptive Behavior Scales – Second Edition (VABS-II);
- Stabilized cortical gray matter volume, which declined in untreated natural history patients, and normalized liver and spleen volume; and
- Generally consistent with the safety profile of intracerebroventricular (ICV) administration; over the six-year study, approximately 6,000 doses were administered to 22 patients.
Read the complete press release from Spruce.
Learn more about the TA-ERT therapy, including timeline of the therapy’s development.