Effectiveness, pharmacokinetics, and safety of a new sustained-release leuprolide acetate 3.75-mg depot formulation for testosterone suppression in patients with prostate cancer: a Phase III, open-label, international multicenter study.

BACKGROUND

A microencapsulated, sustained-release formulation of leuprolide acetate 3.75 mg has been developed.

OBJECTIVE

This study investigated the effectiveness, pharmacokinetics, and safety profile of a 1-month leuprolide acetate 3.75-mg depot formulation for suppressing testosterone concentrations in patients with prostate cancer.

METHODS

This was a Phase III, open-label, international multicenter clinical trial. Patients with prostate cancer who, in the judgment of the investigators, could benefit from androgen deprivation therapy received 6 monthly intramuscular injections of leuprolide acetate 3.75-mg depot. Plasma testosterone concentrations were determined at specific times throughout the study. The primary end point was the proportion of successful patients over the total number of evaluable patients (ie, patients with evaluable testosterone concentrations at all monthly assessments and no missing values due to treatment-related adverse events). Treatment success was defined as testosterone suppression below the clinical castration level (ie,

RESULTS

The study included 160 patients with a mean (SD) age of 71.6 (9.2) years, weight of 83.7 (15.5) kg, and predominantly white race (87.5% [140/160]). All 160 patients received at least one dose of study drug; 157 of them were fully evaluable, and 152 completed the study. The proportion of successful patients over the total number of evaluable patients was 96.8% (152/157; 95% CI,92.7%-99.0%). Five of the 157 evaluable patients (3.2%) did not achieve the primary end point of testosterone concentration

CONCLUSIONS

Leuprolide acetate 3.75-mg depot was effective in achieving and maintaining testosterone suppression and was well tolerated throughout the study in this cohort of patients with prostate cancer. ClinicalTrials.gov identifier: NCT00128531.