Abstract 619P
Background
The maintenance of androgen deprivation therapy (ADT) is the current standard of care in metastatic castration resistant prostate cancer (mCRPC) patients (pts) eligible to docetaxel (D). However, no randomized clinical trials have been conducted to support its efficacy. Furthermore, limited data are available on head-to-head comparison of intermittent versus continuous D schedule.
Methods
In this multicenter, open-label, phase III randomized trial, 198 pts were enrolled between 2010 and 2014. The study was early interrupted due to insufficient accrual. In the first randomization, 96 pts received D 75 mg/m2 every 3 weeks with maintenance of LHRH-A (DL+), while 102 pts received D 75 mg/m2 every 3 weeks with suspension of LHRH-A (DL-). Pts with progression-free disease after 4 D cycles underwent second randomization to receive continuous (35 pts) vs intermittent (42 pts) D therapy. ADT in the DL- arm was restored upon D discontinuation due to disease progression.
Results
PSA response was observed in 43.8% and 38.2 % of DL+ and DL- pts. Median progression free survival (PFS) was 10.3 months in DL+ and 10.8 months in DL- pts (Hazard Ratio [HR] 1.02, 95% confidence interval (CI): 0.76-1.36, p=0.9), the corresponding median overall survival (OS) was 23.3 and 24.8 months, respectively (HR 1.02, 95% CI: 0.75-1.38, p=0.91). Toxicity did not differ in the 2 treatment arms. After six months of therapy, serum testosterone levels raised above the castration range in 23 (22.8 %) DL- pts, while in 6 (5.9%) DL- pts testosterone attained normal levels. No difference in terms of PSA response, PFS and OS was observed comparing pts randomized to continuous versus intermittent D administration.
Conclusions
The efficacy of docetaxel in mCRPC pts is not influenced by the maintenance or suspension of ADT nor by the continuous or intermittent schedule of drug administration.
Clinical trial identification
NCT01224405.
Editorial acknowledgement
Legal entity responsible for the study
Piemonte Oncology Network.
Funding
Piemonte Oncology Network.
Disclosure
All authors have declared no conflicts of interest.