Ultragenyx Pharmaceutical

Ultragenyx Pharmaceutical is a Novato, California-based biopharmaceutical company developing and commercializing therapies for rare and ultra-rare genetic diseases, with four marketed products — Crysvita (burosumab) for X-linked hypophosphatemia, Mepsevii for MPS VII, Dojolvi for long-chain fatty-acid oxidation disorders, and Evkeeza (evinacumab) for homozygous familial hypercholesterolemia. Its late-stage pipeline spans gene therapies and biologics across osteogenesis imperfecta (setrusumab/UX143), Sanfilippo syndrome type A (UX111, AAV9), glycogen storage disease type Ia (DTX401, AAV8), ornithine transcarbamylase deficiency (DTX301, AAV8), and Wilson disease (UX701, AAV9, Phase 2). On September 3, 2026 the company disclosed that its pivotal Phase 3 Aspire study of apazunersen (GTX-102) in Angelman syndrome missed its primary and key secondary efficacy endpoints, triggering a 44% single-day decline, sell-side downgrades, and planned expense reductions.