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Adrenal (Excluding Mineralocorticoids)

SUN-458 - Adults with Classic Congenital Adrenal Hyperplasia Taking Crinecerfont Demonstrated Sustained Decreases in Glucocorticoid Doses: 2-Year Results from the Cahtalyst™ Adult Study

Sunday, June 14, 2026
9:00 AM - 4:00 PM CT
Location: ENDOExpo; Poster Floor
Disclosure(s):
Aled Rees, MD,PhD: Diurnal Ltd: Advisory Board (); Immedica Pharma AB: Honorarium Recipient (); Neurocrine Biosciences: Advisory Board (), Contracted Research (Principal Investigators must provide information, even if received by the institution) (), Honorarium Recipient (); Recordati Rare Disease: Advisory Board ()
Richard J. Auchus, MD,PhD: Adrenas: Contracted Research (Principal Investigators must provide information, even if received by the institution) (); Aspect Biosystems: Consultant (); Crinetics: Consultant (), Contracted Research (Principal Investigators must provide information, even if received by the institution) (); Lundbeck: Consultant (), Contracted Research (Principal Investigators must provide information, even if received by the institution) (); Merck: Consultant (); Neurocrine: Consultant (), Contracted Research (Principal Investigators must provide information, even if received by the institution) (); OMass: Consultant (); Vertex: Consultant ()


Background: Crinecerfont is a novel corticotropin releasing factor type 1 receptor (CRF1) antagonist that is FDA-approved as an adjunct to glucocorticoid (GC) replacement to control androgens in patients (≥4 years) with classic congenital adrenal hyperplasia (CAH), including both salt-wasting and simple virilizing forms. This study evaluated changes in GC doses in adults who received up to 2 years of crinecerfont in the phase 3 CAHtalyst™ Adult trial (NCT04490915).

Methods: Participants who completed the 24-week double-blind placebo-controlled period and 6-month open-label period (Month 12) of CAHtalyst Adult continued taking crinecerfont in an ongoing open-label extension. Mean percent change from baseline (BL) in GC dose (at Months 12, 18, and 24) and percent achieving physiologic GC dose ≤11 mg/m2/d (at Month 24) were assessed while androstenedione (A4) was maintained or improved relative to BL, with decreases in GC doses imputed to zero if A4 was not ≤120% of BL or ≤ upper limit of normal. These outcomes were also assessed based on observed GC dose (i.e., without any imputation based on A4 levels) at Months 18 and 24, when investigators could adjust GC doses according to their clinical judgment, without reference to BL A4.

Results: Of 182 enrolled participants, 92 (51%) were men; mean age was 30.8 years. At BL, the mean (SD) total daily GC dose was 17.6 (4.9) mg/m2/d [32.3 (9.3) mg/d], and mean androstenedione after the morning GC dose was 349 (410) ng/dL. The mean (SEM) percent change from BL in GC dose while maintaining or improving A4 relative to BL was -26% (1.6%) at Month 12, -28% (1.7%) at Month 18, and -25% (1.8%) at Month 24. Moreover, 45% (67/149) of participants achieved a GC dose of ≤11 mg/m2/d while maintaining or improving A4 at Month 24. The observed mean (SEM) percent decrease from BL in GC dose (without imputation based on A4) was -38% (1.2%) at Month 18 and -38% (1.2%) at Month 24, with observed mean GC doses of 10.6 (0.2) mg/m2/d [19.4 (0.5) mg/d] at Month 18 and 10.6 (0.2) mg/m2/d [19.4 (0.5) mg/d] at Month 24. In addition, 71% (114/161) and 69% (103/149) of participants achieved a GC dose in the physiologic range (≤11 mg/m2/d) at Months 18 and 24, respectively, without imputation based on A4. Even with these decreases in GC dose, mean changes from BL in A4 were -11.5 (31.0) ng/dL at Month 18 and +56.6 (29.3) ng/dL at Month 24. Crinecerfont was overall well tolerated; no new safety signals were observed during long-term treatment.

Conclusions: Adults with CAH taking crinecerfont, a novel CRF1 antagonist recently approved for androgen control for patients with CAH, had substantial reductions in GC doses that were maintained for up to 2 years, with more than two-thirds of participants achieving a GC dose in the physiologic range. Crinecerfont is a well-tolerated treatment option for patients with CAH to reduce chronic supraphysiologic GC exposure, which might improve long-term outcomes.

*Unless otherwise noted, all abstracts presented at ENDO must not be released to the press or the public until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.*