RANDOMIZED PHASE II CLINICAL TRIAL: Female subject of childbearing potential should have a negative urine or serum pregnancy within 72 hours prior to registration; if the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required For Phase I and II: Negative urine or serum pregnancy test. Negative serum or urine pregnancy test (investigator's discretion; sensitivity of at least 25 mIU/mL) within 72 hours prior to starting IP in the extension phase. (Note: subjects must have negative serum or urine pregnancy test prior to dosing on Day 1 of each treatment cycle in the extension phase.)