Tildacerfont in Adults With Classic Congenital Adrenal Hyperplasia: Results from Two Phase 2 Studies.

<bold>Context: </bold>Congenital adrenal hyperplasia due to 21-hydroxylase deficiency (21OHD) is typically treated with lifelong supraphysiologic doses of glucocorticoids (GCs). Tildacerfont, a corticotropin-releasing factor type-1 receptor antagonist, may reduce excess androgen production, allowing for GC dose reduction.<bold>Objective: </bold>Assess tildacerfont safety and efficacy.<bold>Design and Setting: </bold>Two Phase 2 open-label studies.<bold>Patients: </bold>Adults with 21OHD.<bold>Intervention: </bold>Oral tildacerfont 200 to 1000 mg once daily (QD) (n = 10) or 100 to 200 mg twice daily (n = 9 and 7) for 2 weeks (Study 1), and 400 mg QD (n = 11) for 12 weeks (Study 2).<bold>Main Outcome Measure: </bold>Efficacy was evaluated by changes from baseline at 8 am in adrenocorticotropic hormone (ACTH), 17-hydroxyprogesterone (17-OHP), and androstenedione (A4) according to baseline A4 ≤ 2× upper limit of normal (ULN) or A4 > 2× ULN. Safety was evaluated using adverse events (AEs) and laboratory assessments.<bold>Results: </bold>In Study 1, evaluable participants with baseline A4 > 2× ULN (n = 11; 19-67 years, 55% female) had reductions from baseline in ACTH (-59.4% to -28.4%), 17-OHP (-38.3% to 0.3%), and A4 (-24.2% to -18.1%), with no clear dose response. In Study 2, participants with baseline A4 > 2× ULN (n = 5; 26-63 years, 40% female) had ~80% maximum mean reductions in biomarker levels. ACTH and A4 were normalized for 60% and 40%, respectively. In both studies, participants with baseline A4 ≤ 2× ULN maintained biomarker levels. AEs (in 53.6% of patients overall) included headache (7.1%) and upper respiratory tract infection (7.1%).<bold>Conclusions: </bold>For patients with 21OHD, up to 12 weeks of oral tildacerfont reduced or maintained key hormone biomarkers toward normal. [ABSTRACT FROM AUTHOR]