Neurocrine Biosciences, Inc.  announced the initiation of its Phase 2 clinical study to assess the safety and tolerability of crinecerfont in children aged 3 months to under 4 years with classic congenital adrenal hyperplasia (CAH). Crinecerfont, marketed as CRENESSITY^®, is approved in the United States as an adjunctive treatment to glucocorticoid replacement to control androgens in adult and pediatric patients 4 years of age and older with classic CAH.

"Infants and young children with classic CAH face significant health challenges and are often exposed to high doses of glucocorticoids during critical periods of growth and development," said Sanjay Keswani, M.D., Chief Medical Officer, Neurocrine Biosciences. "The initiation of this Phase 2 study reflects our commitment to evaluating crinecerfont as a potential treatment option that could reduce the need for long-term supraphysiologic glucocorticoid use and help mitigate the associated risks in this vulnerable, very young population."

CAH is typically identified at or shortly after birth and can lead to life-threatening adrenal crises due to the underlying adrenal insufficiency, as well as androgen excess and consistent dosing of supraphysiologic glucocorticoids – complications for which there are no approved therapies in children under 4 years of age. Neurocrine is conducting this pediatric study under an FDA Pediatric Written Request.

The Phase 2 open-label, single-arm study consists of a 24-week treatment period with a primary objective of assessing the safety and tolerability of crinecerfont in 20 participants aged 3 months to under 4 years with classic CAH. Secondary objectives include evaluation of the pharmacokinetics and pharmacodynamic effects of crinecerfont on hormone biomarkers. This study is expected to support a planned supplemental New Drug Application to expand the approved U.S. indication to include patients less than 4 years of age. Additional information about the trial, including eligibility criteria, can be found at ClinicalTrials.gov.

Separately, Neurocrine achieved target enrollment for a Phase 2 study in the European Union to evaluate the safety and tolerability of crinecerfont in children from birth to under 2 years of age with classic CAH. For more information, visit ClinicalTrials.gov.

Crinecerfont was approved by the U.S. Food and Drug Administration in 2024, marking the first therapeutic advancement in more than 70 years for patients with classic CAH. It is a potent and selective oral corticotropin-releasing factor type 1 receptor (CRF₁) antagonist that reduces elevated adrenocorticotropic hormone (ACTH) secretion at the source and the resulting downstream excess adrenal androgens through a non-GC mechanism.