Extended-Interval Dosing Regimen of a Triptorelin Depot in the Treatment of Advanced Prostate Cancer

Objective: Gonadotrophin-releasing hormone (LHRH) analogues are commonly used in the treatment of advanced cancer of the prostate. Depot administration every 4 weeks is a well-established regimen worldwide. An extended 6-week dosing regimen of a triptorelin depot in patients with prostate cancer (PC) to maintain castration was evaluated for its efficacy and cost-effectiveness. Materials and Methods: From May 2001 through June 2003, 13 patients with advanced PC were given 4 doses of a triptorelin depot of 3.75 mg intramuscularly every 4 weeks, followed by 6 more doses of a triptorelin depot at 3.75 mg at 6-week intervals. Serum prostate-specific antigen (PSA), testosterone, and luteinizing hormone (LH) were measured before and after the serial injections of the triptorelin depot. Results: Castration testosterone levels were achieved in 76.9% and 100% at 1 and 3 months after treatment, respectively. Castration testosterone levels were maintained for 54 weeks in all patients given the extended-interval schedule of the triptorelin depot. PSA levels of less than 0.5ng/ml were observed in 76.9% (10/13) of patients at the end of this study. Cosclusions: The extended 6-week triptorelin depot injection schedule was as effective as the 4-week schedule for maintenance of serum PSA, LH, and testosterone at castration levels in our patients with advanced PC; extended-interval dosing contributed to a 1/3 reduction in treatment costs, without compromising the therapeutic efficacy among our patients.