Spruce Biosciences at H.C. Wainwright: BLA path comes into focus

On Tuesday, September 15, 2026, Spruce Biosciences took the stage at the H.C. Wainwright 28th Annual Global Investment Conference to present a clearer path towards regulatory approval for its lead therapy, tralesinidase alfa. This innovative treatment targets MPS IIIB, a rare neurodegenerative disease. Management highlighted recent FDA discussions that bolstered their confidence, with plans to submit a biologics license application (BLA) in the fourth quarter of 2026.

The company is pursuing accelerated approval based on heparan sulfate levels as a surrogate endpoint, a strategy strengthened by a February 2024 FDA forum. Preclinical data demonstrated rapid and durable biomarker normalization, with functional improvements in cognition, communication, motor skills, and daily living activities. No financial results were disclosed, but Spruce expects to become cash flow positive a few years post-U.S. launch if the therapy receives approval.

CEO Javier Szwarcberg emphasized the company's focus on rare and ultra-rare diseases, aiming for "best in class, ideally first in class." The tralesinidase alfa program leveraged a five-to-six-year clinical dataset previously gathered by BioMarin and Allievex, which included natural history studies, treatment trials, and extension studies. However, the FDA's recognition of heparan sulfate as a reasonable surrogate endpoint in February 2024 transformed the approval landscape into a more viable route.

Spruce had already completed two pre-BLA meetings with the FDA in January 2026, discussing chemistry, manufacturing, and controls and clinical matters. The company expects to file its BLA in the fourth quarter of 2026, aiming for accelerated approval based on biomarker endpoints. Early preclinical data showed near-complete normalization of heparan sulfate in patients, with effects persisting for five years. The therapy demonstrated unprecedented effect sizes compared to competitors in the neuronopathic MPS field.

Functional data, including improvements in cognitive assessments and motor skills, supported the biomarker findings. Side effects were primarily related to the administration device, with no impact on central nervous system efficacy from anti-drug antibodies. The unique enzyme replacement mechanism with an amino acid linker and truncated IGF2 molecule provides a significant barrier to biosimilar development, backed by orphan-drug protection through 2038.