Ultragenyx Pharmaceutical Inc., a development-stage biotechnology company, focuses on the identification, acquisition, development, and commercialization of various products for the treatment of rare and ultra-rare diseases in the United States. It develops various biologics product candidates, including KRN23, a human monoclonal antibody to bind and reduce the biological activity of fibroblast growth factor to enhance abnormally low phosphate levels in patients with X-linked hypophosphatemia; recombinant human beta-glucuronidase, an intravenous enzyme replacement therapy for the treatment of mucopolysaccharidosis 7; and recombinant human protective protein cathepsin-A, an enzyme replacement therapy for galactosialidosis. The company is also developing a range of small-molecule product candidates comprising triheptanoin, a substrate replacement therapy for patients with fatty acid oxidation disorders, as well as for patients with glucose transporter type-1 deficiency syndrome; and oral formulation of sialic acid to treat hereditary inclusion body myopathy. It has license agreements with AAI Pharma Services Corp. and HIBM Research Group; and a collaboration and license agreement with Nobelpharma Co., Ltd. The company was founded in 2010 and is headquartered in Novato, California.