Objective: To evaluate the efficacy and safety of gonadotropin-releasing hormone analogue (GnRHa) triptorelin 11.25 mg 3-month sustained release formulations in the treatment of metastatic prostate cancer.
Methods: From January 2004 to March 2006, a randomized, parallel-controlled, multicenter clinical trial was conducted. One hundred and twenty-seven patients with documented metastatic prostate cancer were randomized to receive one injection of the 11.25 mg formulation triptorelin (n = 65) or three injections at 28-day intervals of the 3.75 mg formulation (n = 62). Changes from baseline of TPSA, prostate volume, testosterone, LH, FSH, PRL and estradiol were assessed over 3 months. Changes of the metastatic lesions were also observed and evaluated. The occurrences of adverse events were evaluated as well.
Results: After 3 months treatment, total PSA level decreased significantly from baseline both in 11.25 mg group and 3.75 mg group. At 30, 60 and 90 days, TPSA (median level) declined from 164.55 microg/L into 11.34, 4.12, 3.89 microg/L in 11.25 mg group, and from 101.38 microg/L into 6.88, 2.41, 2.57 microg/L in control group respectively. The patients ratio with over 90% decreasing from TPSA baseline were 78.6% and 75.5% respectively in two groups (P = 0.700). Prostate volume were also decreased significantly in both groups, median volume declined from 48.0 mm(3) into 21.5 mm(3) in 11.25 mg group and from 45.0 mm(3) into 21.0 mm(3) in 3.75 mg group. No significant differences were found between the two groups in changes of TPSA (P = 0.601) and prostate volume (P > 0.05). Both formulations were able to induce castration levels, 0.31 microg/L in 11.25 mg group and 0.26 microg/L in 3.75 mg group (P > 0.05). 13.8% and 17.7% of adverse events were recorded respectively in two groups, and no differences were found (P = 0.547).
Conclusion: As a new long-acting sustained release formulation, triptorelin 11.25 mg is comparable to triptorelin 3.75 mg formulation in the aspect of efficacy and safety for the treatments of metastatic prostate cancer.