Purpose: We evaluated the pharmacokinetics, safety and efficacy of the implantable Viadur++ leuprolide delivery system during 12 months in patients with advanced prostate cancer.
Materials and methods: Our open label, multicenter, dose ranging study was done in 2 phases. The treatment phase was a stratified, randomized, parallel evaluation of the safety and efficacy of 1 or 2 implants. The safety extension phase assessed the long-term safety and efficacy of 1 implant. Implant insertion and removal, pharmacokinetic profile and patient satisfaction were also evaluated. The primary efficacy parameter was testosterone suppression for 12 months but luteinizing hormone and prostate specific antigen were also evaluated.
Results: Of the 51 patients 27 received 1 and 24 received 2 implants, of whom 49 completed the 12-month treatment phase. Steady serum leuprolide concentration was maintained from day 3 through the remainder of the 12-month treatment phase and for 2 months after reimplantation. Implantation and reimplantation were well tolerated and acceptable to physicians and patients. Testosterone suppression to the castrate range was 100% in each group. At 12 months mean prostate specific antigen decreased from a baseline of approximately 84% and 91% in groups 1 and 2, respectively. Serious adverse events during the study period in 15 patients were not attributable to treatment.
Conclusions: The implantable leuprolide delivery system provides effective suppression of testosterone in patients with advanced prostate cancer.