Feasibility study of a randomized controlled trial comparing docetaxel chemotherapy and androgen deprivation therapy with sequential prostatic biopsies from patients with advanced non-castration-resistant prostate cancer

Abstract

Background and objective: Sequential tissue biopsies taken during clinical trials of novel systemic anticancer therapies for advanced prostate cancer (PCa) may aid pharmacodynamic evaluation and biomarker discovery. We conducted a single institution phase-II open-labeled randomized study to assess the safety, tolerability, and early efficacy of docetaxel chemotherapy plus androgen deprivation therapy (ADT) vs. ADT alone for patients with advanced non-castration-resistant PCa with sequential prostatic biopsies.

Patients and methods: We randomized 30 patients with newly diagnosed high-grade locally advanced or metastatic (cT3-4/N0-1/M0-1) PCa to receive ADT with (n = 15) or without (n = 15) docetaxel. Transrectal ultrasound-guided prostatic biopsies were taken at randomization and ~22 weeks after treatment initiation. Primary end point: biochemical response rate. Secondary end points: time to progression and tumor profiling.

Results: Both treatments appear to be well tolerated, and there was no difference in mean nadir prostate-specific antigen and time to prostate-specific antigen relapse between treatment arms (P>0.05). No adverse effects of pre- and post-treatment prostatic biopsies were observed. The study was neither designed nor sufficiently powered to demonstrate statistically significant differences in oncological outcomes or safety profiles between the 2 treatment arms.

Conclusions: Despite the lack of statistical power, our study suggests that docetaxel and ADT in combination may be well tolerated with apparently similar short-term efficacy compared with ADT alone for high-grade locally advanced or metastatic non-castration-resistant PCa, Sequential prostatic biopsies may provide tissue for tumor profiling to yield mechanistic or prognostic insights relating to novel systemic anticancer therapies.

Keywords: Androgen deprivation therapy; Docetaxel; Prostate cancer; Prostatic biopsy.