Spruce Biosciences Inc. (NASDAQ: SPRB) presented data from a six-year study of tralesinidase alfa enzyme replacement therapy for treating Sanfilippo Syndrome Type B at the 18th International MPS & Related Lysosomal Diseases Symposium in Florence, Italy.

The study analyzed 22 patients who received weekly TA-ERT treatments over six years. The therapy normalized levels of cerebrospinal fluid heparan sulfate non-reducing end, which serves as a surrogate endpoint for clinical benefit in MPS IIIB patients. The treatment stabilized cognitive function, communication skills, and motor abilities compared to untreated patients, according to the company.

"In a progressive neurodegenerative disease like MPS IIIB, stability itself is a clinically meaningful outcome," said Dr. Nicole Muschol from the University Medical Center Hamburg-Eppendorf, who presented the data. "Over six years of treatment, cerebral spinal fluid heparan sulfate fell rapidly and remained low, while cognition, communication, and motor function were preserved relative to the decline seen in untreated patients."

MPS IIIB is a rare genetic disorder affecting fewer than one in 200,000 people in the United States. The condition causes progressive neurodegeneration due to deficiency in the NAGLU enzyme. Patients typically experience cognitive decline, developmental delays, and behavioral changes, with life expectancy ranging from 15 to 19 years. No FDA-approved therapies currently exist for the condition.

TA-ERT is administered through intracerebroventricular injection and has received Breakthrough Therapy Designation, Rare Pediatric Disease Designation, Fast Track Designation and Orphan Drug Designation from the FDA. The therapy also received Orphan Drug Designation in the European Union.

The safety profile remained consistent throughout the six-year study period, with approximately 6,000 doses administered to the 22 patients, according to the press release.