A prostate-specific antigen (PSA) response was defined as a PSA decline from Baseline of 50% or greater, repeated on 2 occasions at least 4 weeks apart.

The Intent-to-treat population, which included all patients enrolled in the study who took at least 1 dose of study medication.

The time from first dosing day to the date of disease progression:

• Progressive measurable disease by RECIST criteria (regardless of bone scan or prostate-specific antigen (PSA) results).
• Development of unequivocal new lesions on bone scan without clinical suspicion of a "flare" reaction.
• In patients who responded or had a decreased PSA from Baseline, a rise of 50% from PSA nadir, if the increase is ≥ 5 ng/mL or back to Baseline and confirmed by a 2nd value.
• In patients with no decrease in PSA from Baseline, a 25% rise over Baseline and ≥ 5 ng/mL confirmed by a 2nd value.

According to the protocol, the sponsor decided to close the study after it was determined that less than 2 of the first 22 patients showed a PSA50 response. Given that all patients discontinued the study due to lack of efficacy, the secondary endpoint of median time to progression was not assessed.

A treatment-related AE was defined as an event with a definite, probable, or possible causality to study medication. A serious AE is an event resulting in death, hospitalization, persistent or significant disability/incapacity, or is life threatening, a congenital anomaly/birth defect or requires medical or surgical intervention to prevent 1 of the outcomes above. The intensity of an AE was graded according to the National Cancer Institute common terminology criteria for adverse events (NCI-CTCAE) version 3.0: Grade 1 (Mild); Grade 2 (Moderate); Grade 3 (Severe); Grade 4 (life-threatening).

The Safety population included all enrolled patients who received at least 1 dose of study medication.

Complete Response (CR) and Partial Response (PR) defined by the Response Evaluation Criteria in Solid Tumor (RECIST) criteria. CR: Disappearance of all target and nontarget lesions. PR: At least a 30% decrease in the sum of the longest diameter of target lesions, taking as reference the baseline sum longest diameter, or persistence of 1 or more nontarget lesion(s) or/and maintenance of tumor marker level above the normal limits.

According to the protocol, the sponsor decided to close the study after it was determined that less than 2 of the first 22 patients showed a PSA50 response. Given that all patients discontinued the study due to lack of efficacy, the secondary endpoint of tumor response rate was not assessed.