Endocrine effects, efficacy and tolerability of a 10.8-mg depot formulation of goserelin acetate administered every 13 weeks to patients with advanced prostate cancer

Abstract

Objective. To determine the endocrine effects, efficacy and tolerability of a 10.8-mg depot formulation of Zoladex®, a luteinizing hormone-releasing hormone agonist analogue, when administration was extended from every 12 weeks to every 13 weeks in patients with advanced prostate cancer. Patients and methods. Between July 1995 and May 1996, 59 patients with either locally advanced (T3 or T4) or metastatic prostate cancer were enrolled in an open-label, multicentre trial. Primary efficacy endpoints were testosterone measurements, and assessments of prostate specific antigen (PSA) response, subjective and objective response. Quality of life (QoL) was a secondary efficacy endpoint. Results. Mean testosterone concentrations decreased to < 0.3 μg/L by week 4 and remained so for the duration of treatment. There were no statistically significant differences in mean testosterone levels between weeks 12 and 13, or weeks 25 and 26. Serum testosterone suppression was adequate in all 58 evaluable patients at week 13, and 51 of 52 (98%) patients at week 26. Of the 58 evaluable patients, 52 (90%) had a PSA response. A subjective response was recorded for six of 11 evaluable patients. Of 58 patients evaluable for objective response, 46 (79%) had a partial response, three (5%) had stable disease and nine (16%) had objective progression. Except for a significant (P = 0.014) decrease in overall sexual interest, QoL was unchanged during therapy. The most common side-effects, regardless of causality, were hot flushes (67%), pain (31%) and pelvic pain (22%). Mild injection-site complaints occurred with only three of 221 (1.4%) depot injections. Conclusions. Zoladex® 10.8-mg depot, administered every 13 weeks to patients with advanced prostatic cancer, is well tolerated, provides adequate suppression of serum testosterone and produces PSA, subjective and objective responses.