Objective was to evaluate the efficacy and safety of the histrelin acetate subdermal implant (originally versus Lupron Depot-3 Month) in male patients with advanced prostate cancer during 52 weeks of treatment with the implant. After consultation w/ FDA, design was modified to eliminate the Lupron arm and continued the study as an open-label non-randomized study.

Primary endpoint was testosterone suppression, as assessed by the percent of patients whose testosterone indicated chemical castration levels (<=50 ng/dL) through 52 weeks of treatment with an implant.

Other outcome measures included serum levels of LH, PSA, as well as non-clinical assessments, eg, WHO Performance Status, pain level assessment, and quality of life questionnaires. Safety was evaluated via adverse events, vital signs, clinical laboratory outcomes, physical examinations, and ECGs. Local tolerability outcomes were also evaluated.

An extension period for the study included annual replacement of the implant until the implant was approved by the FDA (October 12, 2004). Efficacy and safety were followed during the extension period.

Key Inclusion Criteria:

• Male Age 45 or older
• Histologically confirmed adenocarcinoma of the prostate
• Disease Staging III or IV
• Clinical indication for androgen suppression therapy
• Serum testosterone at least 150 ng/dL at screening
• WHO Performance Scale 0 to 3
• Life expectancy of at least one year

Key Exclusion Criteria:

• Bilateral orchiectomy
• Prior androgen-ablative therapy within past year
• Second malignancy with 5 years (except adequately treated non-melanomatous skin cancer or superficial bladder cancer)
• Spinal cord compression