PRIORITI: Phase 4 study of triptorelin or active surveillance in high-risk prostate cancer.

Abstract

To evaluate the efficacy and safety of triptorelin after radical prostatectomy (RP) in patients with negative lymph nodes. PRIORITI (NCT01753297) was a prospective, open-label, randomized, controlled, phase 4 study conducted in China and Russia. Patients with high-risk (Gleason score ≥ 8 and/or pre-RP prostate-specific antigen [PSA] ≥ 20ng/mL and/or primary tumor stage 3a) prostate adenocarcinoma without evidence of lymph node or distant metastases were randomized to receive triptorelin 11.25mg at baseline (≤ 8weeks after RP) and at 3 and 6 months, or active surveillance. The primary endpoint was biochemical relapse-free survival (BRFS), defined as the time from randomization to biochemical relapse (BR; increased PSA>0.2ng/mL). Patients were monitored every 3 months for at least 36 months; the study ended when 61 BRs were observed. The intention-to-treat population comprised 226 patients (mean [standard deviation] age, 65.3 [6.4] years), of whom 109 and 117 were randomized to triptorelin or surveillance, respectively. The median BRFS was not reached. The 25th percentile time to BRFS (95% confidence interval) was 39.1 (29.9-not estimated) months with triptorelin and 30.0 (18.6-42.1) months with surveillance (p=0.16). There was evidence of a lower risk of BR with triptorelin versus surveillance but this was not statistically significant at the 5% level (p=0.10). Chemical castration was maintained at month 9 in 93.9% of patients who had received triptorelin. Overall, triptorelin was well tolerated and had an acceptable safety profile. BRFS was observed to be longer with triptorelin than surveillance, but the difference was not statistically significant.