A Study to Assess the Safety and Efficacy of Levoketoconazole in the Treatment of Endogenous Cushing's Syndrome.

Brief Summary:
This is a double-blind, randomized, placebo-controlled withdrawal and rescue/restoration study in subjects with endogenous CS previously treated with single-arm, open-label levoketoconazole that will assess efficacy, safety, tolerability, and pharmacokinetics of levoketoconazole

Detailed Description:
This is a double-blind, randomized, placebo-controlled withdrawal and rescue/restoration study in subjects with endogenous CS that will assess efficacy, safety, tolerability, and PK of levoketoconazole. There are two populations (cohorts) of subjects: (1) subjects which were previous levoketoconazole study completers and (2) subjects that are levoketoconazole treatment naïve subjects.

Study methodology varies by cohort prior to randomization only. Following initial screening (washout as needed) and Dose Titration and Maintenance Periods, as applicable, this study will be conducted in two double-blind phases (a Withdrawal Phase and a Restoration Phase). The levoketoconazole-naïve cohort will need to go through the Dose Titration and Maintenance Phase. The longest anticipated total study participation duration is approximately 51 weeks.

Study Type: Interventional  (Clinical Trial)
Estimated Enrollment: 54 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: A Double-blind, Placebo-Controlled, Randomized Withdrawal Following Open Label Therapy Study to Assess the Safety and Efficacy of Levoketoconazole (2S, 4R-ketoconazole) in the Treatment of Endogenous Cushing's Syndrome
Actual Study Start Date: September 26, 2017
Estimated Primary Completion Date: December 1, 2019
Estimated Study Completion Date: February 28, 2020

Arms:
- Experimental: Levoketoconazole
- Placebo Comparator: Placebo