Spruce Biosciences Inc. (NASDAQ: SPRB) has completed pre-Biologics License Application (BLA) meetings with the U.S. Food and Drug Administration (FDA) for its investigational enzyme replacement therapy, tralesinidase alfa, intended to treat Sanfilippo Syndrome Type B (MPS IIIB).
The company plans to submit its BLA in the fourth quarter of 2026, following the completion of two pre-BLA meetings with the FDA. These discussions addressed the clinical and manufacturing data required for the application, including the design of a confirmatory study that may commence during the BLA review process. Spruce also finalized agreements with the regulator on the structure of integrated efficacy and safety summaries, as well as analytical comparability strategies for drug substance and product manufacturing.
Tralesinidase alfa has been administered to 22 individuals with MPS IIIB across three clinical studies. The ultra-rare genetic disorder, which affects fewer than one in 200,000 people in the U.S., is characterized by a deficiency in the alpha-N-acetylglucosaminidase enzyme, leading to progressive neurodegeneration. No FDA-approved therapies currently exist for the condition.
Spruce has transferred drug substance and product manufacturing to a biologics manufacturer to establish commercial-scale capabilities. The company manufactured its first process performance qualification batch in July 2026, with data to be included in the BLA submission. A second qualification batch is expected to be completed by the midcycle of the BLA review, providing additional data to support the application.
The therapy holds multiple designations from the FDA, including Breakthrough Therapy, Fast Track, Rare Pediatric Disease, and Orphan Drug status. In the European Union, it has received Orphan Drug Designation. Upon approval, the product may also qualify for a rare pediatric disease priority review voucher.
