Allievex

Allievex Corporation was a clinical-stage biotechnology company founded by Pappas Capital and headquartered in Marblehead, Massachusetts, dedicated to developing novel therapies for children with rare pediatric neurodegenerative diseases. Its lead product candidate, tralesinidase alfa (AX 250), was an investigational enzyme replacement therapy licensed from BioMarin Pharmaceutical targeting Sanfilippo syndrome type B (MPS IIIB), a devastating lysosomal storage disease. The company completed a Series A financing co-led by Novo Holdings and Pappas Capital in October 2019 to fund Phase 2 clinical studies. After failing to reach alignment with the FDA on its development path, Allievex terminated all business operations and clinical studies in October 2023. The AX 250 program was subsequently acquired by Spruce Biosciences in April 2025.