SUN-405 Crinecerfont Shows Favorable Trends in Improving Weight-Related Outcomes in Adults With Classic Congenital Adrenal Hyperplasia: 1-Year Results From the CAHtalyst™ Adult Study

Abstract Disclosure: I. Bancos: None. H. Falhammar: None. J. Young: None. R. Pivonello: Received research funding from Corcept Therapeutics, Neurocrine Biosciences, Recordati AG, Spruce Bioscience and Xeris Pharmaceuticals (Strongbridge Biopharma), Consultant for Corcept Therapeutics, Crinetics Pharmaceuticals, HLundbeck A/S and Recordati Rare Diseases.. G. Russo: None. M.R. Stancampiano: None. V.H. Lin: Full-time employee of Neurocrine Biosciences, Inc. J. Sturgeon: Full-time employee of Neurocrine Biosciences, Inc. J.L. Chan: Full-time employee of Neurocrine Biosciences, Inc. Background: In patients with classic congenital adrenal hyperplasia (CAH), chronic glucocorticoid (GC) treatment, especially at supraphysiologic doses, can lead to weight gain or obesity. Crinecerfont, a corticotropin releasing factor type 1 receptor (CRF1) antagonist, is a first-in-class medication that is FDA-approved for adjunctive treatment to GC replacement to control androgens in patients with CAH. In CAHtalyst™ Adult (NCT04490915), least-squares mean (LSM) percent changes in GC dose at Week 24 (end of double-blind placebo-controlled [DBPC] period) indicated a significant reduction with crinecerfont (-27.3% vs 10.3% for placebo; LSM difference [LSMD] -17.0%; P<0.0001) while androstenedione was maintained or improved relative to Day 1 baseline (BL). At Month 12 (end of open-label [OL] period), mean percent decreases from BL were -24.6% in participants continuing crinecerfont (CFT/CFT) and -29.7% in those switched from placebo (PBO/CFT). Objective: To evaluate weight-related outcomes in adults with CAH who received up to 1 year of crinecerfont. Methods: Mean change from Day 1 BL in body mass index (BMI) and mean percentage change from BL in weight were analyzed at Week 24 and Month 12. Achievement of >5% reduction in weight was also analyzed, with results presented as % (n/N: n=number meeting response threshold, N=number who were overweight/obese [BMI ≥25 kg/m2]) at BL and had available data at assessment [Week 24 and Month 12]). For predefined endpoints in the DBPC period, results are presented as LSM changes with LSMD and P-value. Results: Mean BMI at BL was 30.1 kg/m2 (crinecerfont) and 29.0 kg/m2 (placebo), and >70% of participants were overweight or obese (74.6% [91/122] crinecerfont; 63.3% [38/60] placebo). At Week 24, LSM changes from BL for crinecerfont vs placebo were as follows: BMI (-0.42 vs -0.02; LSMD: 0.40, P=0.1068); percent change in weight (1.45% vs -0.07%; LSMD: 1.38%, P=0.0856). At Month 12, further mean reductions from BL were observed with crinecerfont in BMI (-0.81 kg/m2 CFT/CFT, -0.44 kg/m2 PBO/CFT) and weight (-2.72% CFT/CFT, -1.37% PBO/CFT). Among participants who were overweight or obese at BL, a higher percentage achieved >5% reduction in weight at Week 24 with crinecerfont 18.4% (16/87) versus placebo 13.5% (5/37). At Month 12, 27.4% (23/84) and 38.9% (14/36) achieved this threshold in the CFT/CFT and PBO/CFT groups, respectively. Conclusion: Adults with CAH who received up to 1 year of crinecerfont showed reductions in BMI and weight. Among participants who were overweight or obese at BL, 30.8% achieved a >5% reduction in weight at Month 12. These analyses indicate that the substantial GC dose reductions enabled by crinecerfont can allow for improvements in the weight-related effects associated with chronic supraphysiologic GC exposure. Presentation: Sunday, July 13, 2025