A First-in-human Study of KK8123 in Adults With X-linked Hypophosphatemia

Study 8123-001 is a Phase 1/2, multicenter, open-label, dose-escalation study to assess the safety, tolerability, PK and PD of KK8123, with an optional safety extension period. This study is comprised of a Screening Period followed by Part 1 and Part 2. The Screening Period will last up to 35 days (including obtaining informed consent). Part 1 is a Dose Escalation Period consisting of a nominal (planned) Treatment Period (all cohorts) followed by an Observation Period, and Part 2 is an optional Extension Period.