A Study in Pediatric Participants With Congenital Adrenal Hyperplasia (Balance-CAH)

This Phase 2/3 plus open-label extension study is designed to evaluate the safety, efficacy, pharmacokinetics (PK), and pharmacodynamics (PD) of atumelnant treatment in pediatric participants with classic CAH. Part A is a Phase 2, open-label, semi-sequential cohorts portion of the study. Part B is the Phase 3, double-blind, randomized, placebo controlled confirmatory portion of the study. Part C is the open-label extension (OLE) portion of the study. Participants in Part A and B are eligible to enroll in Part C (OLE). A total of approximately 153 participants may be enrolled in the study (planned and optional cohorts) ages 1 to \< 18 years old. The first 3 cohorts in Part A are for ages 12 to \<18 years and will be semi-sequential, and Safety Review Committee (SRC) review of data and approval to proceed is required prior to enrolling each subsequent cohort. The fourth cohort in Part A is for ages 1 to 11 years old and will begin after Cohorts 1 and 2 have been completed, additional requirements are fulfilled, and following SRC review of Cohorts 1 and 2 data.