Inclusion Criteria:

• Male or female.
• 18 to 80 years of age, inclusive.
• Lack of cortisol suppression (> 1.8 μg/dL serum cortisol with adequate dexamethasone levels) on either 1-mg overnight or 2-mg 48-hour DST during Screening.
• Suppressed or low (≤15 pg/mL) early-morning ACTH levels on at least 2 occasions during Screening.
• A radiologically confirmed benign adrenal lesion (single adenoma, multiple adenomas, hyperplasia [≥ 3 times the size of the normal adrenal gland]) within 3 years prior to screening
• Has at least 1 of the following at Baseline:
  • DM (fasting plasma glucose ≥ 126 mg/dL and/or 2-hour oGTT plasma glucose ≥ 200  mg/dL at 2 hours, or HbA1c ≥ 6.5%), or IGT (plasma glucose ≥ 140 mg/dL and < 200 mg/dL on a 2-hour oGTT) (American Diabetes Association 2020);
  • Systolic hypertension (mean SBP ≥ 130 to ≤ 170 mm Hg) based on 24-hour ABPM (Parati et al. 2014).
• If receiving medical treatment for DM/IGT or hypertension,there has been no increase in medication dosage for at least 4 weeks prior to Baseline assessment.
• For women of childbearing potential, has a negative serum pregnancy test at Screening and negative urine pregnancy test at Baseline.

Exclusion Criteria:

• Has severe, uncontrolled hypertension (mean SBP > 170 mm Hg or mean DBP > 110 mm Hg at Screening), based on 24-hour ABPM.
• Has poorly controlled DM (HbA1c > 12% at Screening).
• Has DM Type 1. 
• Has abnormal liver test results (total bilirubin >1.5 × ULN or elevated alanine aminotransferase or aspartate aminotransferase > 3 × ULN at Baseline).
• Has severe renal insufficiency (glomerular filtration rate ≤ 29 mL/min at Baseline).
• Has uncontrolled, clinically significant hypothyroidism or hyperthyroidism.
• Has prolonged QT interval corrected for heart rate using Fridericia’s equation (QTcF) (> 450 ms for men and > 470 ms for women) with normal QRS interval (500 ms with wide QRS interval (≥ 120 ms).
• Has persistent atrial fibrillation.
• Has used or plans to use any treatments for Cushing syndrome within 12 weeks prior to Screening and throughout the study, including mifepristone, metyrapone, osilodrostat, ketoconazole, fluconazole, or any investigational drug for treatment of Cushing syndrome.
• Patients who require inhaled glucocorticoids and have no alternative option if their condition deteriorates during the study.
• Has adrenocortical carcinoma.
• Has pseudo-Cushing syndrome. Patients with known or suspected pseudo-Cushing syndrome based on medical history (such as patients with severe obesity, major depression, or a history of alcoholism) should undergo a dexamethasone-CRH/DDAVP stimulation test (Yanovski et al.1993, Giraldi et al. 2007, Yanovski et al. 1998) to rule-in or rule-out this possibility.
• Has a history of cyclic Cushing syndrome with fluctuating clinical manifestations.
• Has autonomous cosecretion of aldosterone.
• Has plans for adrenalectomy or nodulectomy during the study, including follow-up.
• Has taken any non-Cushing syndrome investigational drug within 4 weeks prior to Baseline, or within less than 5 times the drug’s half-life, whichever is longer.
• Ongoing use of antidiabetic, antihypertensive, antidepressant or lipid-lowering medications that are highly dependent on CYP3A for clearance and that cannot undergo dose modification upon coadministration with strong CYP3A inhibitors.
• Ongoing use of any strong CYP3A4 inducer or any other prohibited medications.
• Is pregnant or lactating.
• Is a female patient of childbearing potential who cannot use a highly effective method of contraception (including all women < 50 years old, women whose surgical sterilization was performed < 6 months ago, and women who have had a menstrual period in the last 2 years).
• Has an acute or unstable medical problem that could be aggravated by treatment with the investigational study drug.
• Has a history of severe reaction to the study drug, to a similar class of drug, or to the study drug’s excipient.
• In the Investigator’s opinion, should not participate in the study or may not be capable of following the study schedule.
• Has known HIV, hepatitis B, or hepatitis C infection and is taking medication for treatment of HIV, hepatitis B, or hepatitis C infection.
• Has used mitotane prior to Baseline.

Eligibility last updated 2/16/22. Questions regarding updates should be directed to the study team contact.