Exhibit 99.1 Contacts Ultragenyx Pharmaceutical Inc. Investors Joshua Higa ir@ultragenyx.com Ultragenyx Reports Second Quarter 2025 Financial Results and Corporate Update Second quarter total revenue of $166 million, Crysvita® revenue of$120 million and Dojolvi® revenue of $23 million Reaffirm 2025 Revenue Guidance: Total revenue between$640 million to $670 million, Crysvita revenue of$460 million to $480 million, and Dojolvi revenue of$90 million to $100 million UX143 for osteogenesis imperfecta Phase ...