Exhibit 99.1 Rusfertide NDA accepted and granted Priority Review by FDA, with a Prescription Drug User Fee Act target action date in the third quarter of 2026 Protagonist exercised its rusfertide opt-out right under the Takeda collaboration on April 28, triggering a $200 million opt-out fee payable to the Company; eligible for additional $200 million opt-out and $75 million milestone payments upon NDA approval, sales milestones of up to $775 million and worldwide royalties ranging from 14% to 29% PN-881 (or ...