A 6-month depot formulation of leuprolide acetate is safe and effective in daily clinical practice: a non-interventional prospective study in 1273 patients

Abstract

Background: Testosterone stimulates growth in many prostate tumours. The established GnRH analogue leuprolide acetate is incorporated in a novel biodegradable polymer matrix (Atrigel® delivery system), that can be administered to reduce testosterone levels in men with advanced hormone-dependent prostate cancer. This novel formulation is available as a 1-, 3- and most recently 6-month depot (Eligard® 45 mg). The latter was shown to lower and maintain safe and effective serum testosterone suppression in a clinical study.

Methods: A non-interventional study to confirm the efficacy and safety of 6-monthly leuprolide acetate (Eligard® 45 mg) in routine urological practice was performed in Germany. Data were obtained from 1273 patients under the care of 634 urologists, and were analysed descriptively. Concentrations of PSA and serum testosterone were documented at the baseline visit and at 6 and 12 months following 6-monthly leuprolide acetate. The participating physicians were also asked to assess the efficacy, tolerability and handling of 6-monthly leuprolide acetate.

Results: Serum concentrations of PSA and testosterone were decreased substantially within 6 months of initial 6-monthly leuprolide acetate administration. At 12 months, median reductions of 96% (to 0.5 ng/ml) in PSA, and 90% (to 8.9 ng/dl) in serum testosterone, were observed. Further PSA and serum testosterone decreases were also observed in a subpopulation of patients who switched to 6-monthly leuprolide acetate from other GnRH analogues. Physicians rated 6-monthly leuprolide acetate as easy to use, and patients reported good tolerability. Adverse events occurred in 9% of patients; the majority were not serious. In particular, low rates of hot flushes were reported.

Conclusions: This non-interventional study showed that the reliable reduction of PSA and testosterone levels demonstrated in previous clinical studies of twice-yearly leuprolide acetate can also be achieved in routine clinical practice. This study also confirmed good tolerability of 6-monthly leuprolide acetate in routine clinical use and received positive appraisal from physicians.

Figure 1

Median serum concentrations of PSA and testosterone during treatment with 6-monthly leuprolide acetate.

Figure 2

Final assessment of 6-monthly leuprolide acetate therapy by the participating urologists. Legend. Diagnosis and treatment decisions were at the sole discretion of the treating physicians. The physicians stated that the most frequent reasons for choosing 6-monthly leuprolide acetate were the long dosage interval, small injection volume, and short cannula. Less frequent reasons for choosing 6-monthly leuprolide acetate included compliance/patient's request, costs, physician's interest in 6-monthly leuprolide acetate, and good efficacy of the Astellas leuprolide acetate. Other reasons were named in minor frequencies.