Phase II, Open Label, Dose Finding Study of the Effect of GTx-758 on Total and Free Testosterone Levels in Men With Prostate Cancer Compared to a Luteinizing Hormone Releasing Hormone Agonist

Inclusion Criteria:

1. be between age 45 and 80 years of age

2. be able to communicate effectively with study personnel

3. ECOG is < or = 2

4. screening serum total testosterone> or = 150ng/dL

5. have prostate cancer, confirmed by pathology report

6. have not been treated with androgen deprivation therapy(chemical or surgical

7. have a clinical indication for the initiation of androgen deprivation therapy

8. give written informed consent prior to any study specific procedures

9. subject must agree to use acceptable methods of contraception

Exclusion Criteria:

1. known hypersensitivity or allergy to estrogen or estrogen like drugs

2. a clinically significant concurrent illness or psychological, familial, sociological,
geographical or other concomitant condition that would not permit adequate follow-up
and compliance with the study protocol

3. history of abnormal blood clotting,Factor V Leiden clotting disorder, thrombotic
disease

4. have ALT or AST above 2 times the upper normal limit

5. have alkaline phosphatase greater than 3 times UNL and/or bilirubin levels above
2mg/dL at baseline

6. patients cannot have brain or spinal cord metastases

7. patients cannot have or be at risk for spinal cord compression from bone metastases

8. received an investigational drug within a period of 90 days prior to enrollment in
the study

9. received the study medication previously

10. currently taking testosterone, testosterone-like agents, or antiandrogens including
5-alpha reductase inhibitors within 4 weeks of randomization

11. currently taking Saw Palmetto or PC-SPES (the subject may be considered for
randomization after a 4 week washout period prior to randomization)

12. have taken diethylstilbestrol or other estrogen products within the previous 12
months prior to randomization

13. have taken body building or fertility supplements within 4 weeks of admission into
the study (steroids and steroid like supplements)

14. have a history of cancer other than prostate cancer, superficial bladder cancer (with
no recurrence in the last 5 years) and/or non-melanoma carcinoma of the skin

15. QTcB>480 msec, If the first QTcB reading exceeds 480msec two additional ECGs are to
be performed separated at least 5 min apart, then take the average of the three QTcB
or readings to determine if the subject satisfies the above criteria. If the average
QYcB reading is >480 msec then the subject is excluded.