To evaluate the effect of tildacerfont in reducing A4 (androstenedione) in subjects with CAH (Congenital Adrenal Hyperplasia) over 12 weeks.

Participants will be asked to complete 15 study visits (done in-clinic or via telemedicine) and at least 4 telephone contacts. Some study visits require fasting (no food after midnight and nothing to drink except water after 8 pm). During the study visits, participants will provide information regarding their health and medications, and undergo a physical exam. Fasting blood and urine samples will be collected during the visits and participants will have an electrocardiogram (ECG). Participants will be required to do the following: • Give correct and accurate information about your medical history, medication list, and current medical condition • Take their glucocorticoids and study drug dose as instructed by study doctor and record everything in their electronic diary (eDiary) • Carry their Patient Emergency Card with them at all times while participating in this study • Talk to the study doctor before taking any new medication during the study. • Complete their acne assessments every 4 weeks in your eDiary • Female participants may be required to enter menstrual information and complete the assessment of unwanted, male-pattern hair growth every 4 weeks in your eDiary • Male participants may be required to have a scrotal ultrasound • Tell the study doctor about any side effects or problems that you experience during the study • Follow birth control requirements • Do not eat grapefruit or drink grapefruit juice during your participation in the study • Do not participate in heavy exercise for 8 hours before any visit where blood samples will be drawn and in any type of exercise within 30 minutes before any study procedure

$1200