Upon joining the study, the patient will be assessed to ensure they meet the necessary criteria, such as age, weight, and medical history related to classic congenital adrenal hyperplasia (CAH).

The patient must be on a stable glucocorticoid treatment regimen and have elevated adrenal androgens.

The patient will be randomly assigned to receive either crinecerfont (NBI-74788) or a placebo. The medication will be administered orally, either as a solution or in capsule form.

The primary goal during this phase is to evaluate the reduction in adrenal steroid levels while maintaining a stable glucocorticoid regimen.

At week 4, the patient’s serum androstenedione levels will be measured to assess changes from the baseline.

Additionally, serum 17-hydroxyprogesterone levels will be evaluated to determine any changes from the baseline.

Following the initial randomized phase, the patient will enter an open-label treatment phase where they will receive crinecerfont.

This phase allows for continued monitoring and assessment of the medication’s efficacy and safety.

At week 28, the patient’s glucocorticoid dose will be reviewed to determine any percentage change from the baseline.

This evaluation helps in understanding the long-term impact of crinecerfont on glucocorticoid requirements.

After completing the treatment phases, the patient will return for a follow-up visit to ensure their well-being and to gather additional data on the treatment’s effects.