SPRUCE BIOSCIENCES, INC.

TA-ERT Program Updates

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BLA submission for TA-ERT for the treatment of MPS IIIB anticipated in the fourth quarter of 2026: Spruce continues to advance manufacturing readiness, regulatory interactions and commercial planning to support an anticipated BLA submission in the fourth quarter of 2026, seeking accelerated approval based on cerebrospinal fluid heparan sulfate non-reducing end (CSF HS-NRE) as a reasonably likely surrogate endpoint of clinical benefit. 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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TrAnsform confirmatory study required for potential FDA accelerated approval of TA-ERT expected to initiate in the fourth quarter of 2026: The planned TrAnsform confirmatory study is a randomized, single-blind, parallel-group, controlled, multicenter study evaluating the safety, tolerability and efficacy of intracerebroventricular (ICV)-administered TA-ERT compared to standard of care in children 1 to 5 years of age with severe (non-attenuated) MPS IIIB. The study is expected to enroll approximately 14 participants, with the primary objective of evaluating the effect of TA-ERT on cognition. As a condition of potential FDA accelerated approval of TA-ERT, the FDA requested that the company initiate the TrAnsform confirmatory study while the planned BLA submission for TA-ERT is under review. More information about the TrAnsform confirmatory study can be found at ClinicalTrials.gov.