UX701 is an experimental gene therapy for Wilson disease, delivered via adeno-associated virus, that restores a functional version of the ATP7B gene.
UX701 is currently being evaluated in a pivotal Phase 1/2/3 study known as Cyprus2+. In October 2024, interim data from the first three cohorts (15 patients) showed that 6 patients successfully tapered off standard-of-care chelator or zinc therapies while maintaining stable copper levels. Based on these results, Ultragenyx announced plans to add a fourth cohort to Stage 1 of the trial using a higher dose and an optimized immunomodulation regimen to further evaluate efficacy before moving into the Stage 2 dose expansion study.