A Study to Evaluate the Safety and PK of CRN04894 for the Treatment of Cushing's Syndrome

Inclusion Criteria: 1. Adult male or female, aged 18 years or more 2. Evidence of chronic 'active' ACTH-dependent Cushing's syndrome 3. Evidence of acutely 'active' ACTH-dependent Cushing's syndrome within 10 days of Day 1 4. Participants with documented ACTH-dependent Cushing's syndrome taking short-acting steroidogenesis inhibitors (ketoconazole, levoketoconazole, osilodrostat, or metyrapone) may participate after a washout period of at least 5 days, if they meet other study inclusion criteria, relative to Investigator's judgment. Participants with documented ACTH-dependent Cushing's syndrome taking cabergoline may participate after a washout period of at least 14 days, if they meet other study inclusion criteria Exclusion Criteria: 1. Women who are pregnant or lactating 2. History of bilateral adrenalectomy 3. Previous pituitary MRI findings of a putative ACTH-secreting lesion within 3 mm of the optic chiasm 4. Presence of any known malignancy 5. Use of mitotane 6. Previous unsuccessful surgery for Cushing's syndrome within 6 weeks