This will be a phase 1/2a, open-label, single-center study with 3 periods. The aims of the study are to: 1) evaluate the dose-response curve following ascending single doses of TSX-011; 2) confirm optimum dosing conditions; 3) evaluate the efficacy of single or multiple daily adaptive dosing; and 4) evaluate the safety and tolerability of TSX-011. Up to 24 hypogonadal men will be enrolled in this study to yield 16 evaluable subjects, and it is desired that the same 24 subjects participate in all 3 study periods.~Period 1 is an ascending single-dose study of TSX-011 at 3 doses, with the lowest dose administered under fed and fasted conditions: 190 mg TSX-011 in the fed state, 190 mg TSX-011 in the fasted state, 380 mg TSX-011 in the fed state, and 570 mg TSX-011 in the fed state. Before exposure to TSX-011, a 24 hour baseline measurement of testosterone and DHT will be performed for each subject. Samples for analysis of testosterone will be obtained at the following time points on Day -1: hour 0 (8 am ± 60 minutes) and 1.5, 3, 4.5, 6, 8, 12, 16, and 24 hours (± 15 minutes for each time point).~The day following the sampling for endogenous testosterone (Day 1) in Period 1, each subject will receive the first single dose of TSX-011 (190 mg) under fed conditions. Following administration of TSX-011, blood samples will be obtained over a 24-hour period for PK analysis. Subjects will undergo a minimum 3-day and up to 7-day washout period between each of the doses of TSX-011 in Period 1. After the 570 mg TSX 011 dose in Period 1, a minimum 3-day and up to 7-day washout period will occur before the start of Period 2.~Period 2 is a twice-daily dosing period, where fed subjects will be dosed with 380 mg TSX-011 twice daily for 15 days (Days 1 through 15). Pharmacokinetic assessments over 24 hours will occur on Days 1 and 15. The TSX-011 dose will be titrated up or down beginning with the Day 16 (Period 3) morning dose, based on established dosing rules.~Period 3 is a dose-adjusted adaptive design period that begins on Day 16, with the first adjusted TSX-011 dose administered in the fed state on a once-daily or twice-daily schedule. The 6-hour postdose (± 15 minutes) testosterone level on Day 19 will be used to perform the second and final TSX-011 dose adjustment, based on established criteria. As specified by the dose adjustment rules, Day 26 begins with either a once-daily, twice-daily, or thrice-daily fed dose schedule. The thrice-daily dose schedule will be administered only to non-responders. On Day 30, a 24 hour PK assessment will be performed, and the subject's participation in the study is completed the morning of Day 31.
This will be a phase 1/2a, open-label, single-center study with 3 periods. The aims of the study are to:~evaluate the dose-response curve following ascending single doses of TSX-011;~confirm optimum dosing conditions;~evaluate the efficacy of single or multiple daily adaptive dosing; and~evaluate the safety and tolerability of TSX-011.