This study will assess possible drug-drug interactions with specific isoenzymes over a total study duration of 6-8 weeks. Blood samples collected pre and post-dose, and urine samples collected post dose will be analyzed.

This is an open-label, multiple-dose, non-randomized study to assess the drug-drug interactions of Proellex® with cytochrome P450 isoenzymes in healthy female subjects. On Day 1, following an overnight fast and morning void of the bladder, subjects will be administered CYP probe drugs orally. Serial blood samples will be collected at pre-dose and post-dose. Subjects will be administered two Proellex® 25 mg capsules (50 mg total dose) at approximately 0800 hours on Day 2 and 0700 hours on Days 3 through 8. One hour after administration of Proellex® on Day 8, the five CYP probe drugs will be administered and blood and urine samples collected as on Day 1. Blood samples for the determination of plasma concentrations of CDB-4124 and its metabolite CDB-4453 will be collected at pre-dose (trough) on Days 6, 7, and 8 to determine if steady-state conditions have been achieved. Samples will also be collected on Day 8 at 1, 2, 8 and 24 hour after administration of Proellex® to determine the plasma concentrations of CDB-4124 and CDB-4453.

Inclusion Criteria:

• Healthy adult females
• A body mass index between 18 and 30 kg/m2, inclusive
• Negative urine drug and alcohol screen .

Exclusion Criteria:

• Significant medical condition,
• Significant physical examination finding
• Clinical laboratory
• ECG abnormality
• CYP2D6 "poor metabolizer"

All subjects enrolled