Exhibit 99.1 Mirum Pharmaceuticals Reports First Quarter 2025 Financial Results and Provides Business Update – First quarter 2025 total revenue of $111.6 million; 2025 guidance increased to$435 to $450 million – VISTAS study in PSC expected to complete enrollment in third quarter of 2025; topline data expected in second quarter of 2026 – LIVMARLI oral tablet formulation FDA approved – Conference call to provide business updates today, May 7 at 1:30 p.m. PT/4:30 p.m. ET FOSTER CITY, Calif. – May 7, 2025 - M ...