Treatment outcomes for patients with metastatic castrate-resistant prostate cancer following docetaxel for hormone-sensitive disease

Aim Optimal treatment for newly diagnosed metastatic hormone-sensitive prostate cancer (mHSPC) has evolved, with many patients deriving benefit from the addition of docetaxel to androgen deprivation therapy (D-ADT). This study sought to define the therapy used and associated activity following D-ADT. Methods Retrospective analysis of patients with mHSPC treated with one or more cycles of D-ADT who were identified from a prospectively maintained multisite prostate cancer database of patients treated in a community or academic center setting in Australia. The primary endpoint of this study was first-line time to treatment failure (1L TTF) for subsequent treatment of metastatic Castrate Resistant Prostate Cancer (mCRPC), with secondary endpoints of prostate-specific antigen (PSA) reduction >50% and time from 1L to second-line (2L) treatment initiation. Results A total of 93 patients received D-ADT for mHSPC, 85 (91%) had subsequent treatment for mCRPC. Median time to mCRPC (biochemical, clinical or radiographic) had been 14.8 months (95% confidence interval [CI], 11.9-16.5). 1L treatment was enzalutamide 47 patients (55%), abiraterone 23 (27%), cabazitaxel 7 (8%), docetaxel 4 (5%) and other therapies 4 (5%). Median 1L TTF was 6.3 months (95% CI, 4.9-7.6), PSA > 50% reduction was achieved in 32 of 89 patients (36%), median time from 1L to second-line treatment was 7.3 months (1.3-27.4), which did not differ significantly between treatment groups. Conclusions Abiraterone, enzalutamide, cabazitaxel and docetaxel all demonstrate activity following progression on D-ADT. No difference in efficacy was detected between treatment options for mCRPC. Prospective trials investigating the optimal treatment sequence for prostate cancer following progression on D-ADT needed.