Sequencing new agents after docetaxel in patients with metastatic castration-resistant prostate cancer

Background: Two new hormonal agents (NHAs), abiraterone and enzalutamide, and one chemotherapeutic agent, cabazitaxel (CABA) improved overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) who progress after docetaxel. Although several analyses of patient cohorts receiving a sequence of two different new agents (NAs) after docetaxel have been published, no definite conclusions can be drawn regarding the best treatment strategy. Materials and methods: All published studies reporting monthly OS rates of mCRPC patients receiving third-line NA after having previously received docetaxel and another NA have been analyzed. The treatments were merged into three groups: one NHA followed by another, one NHA followed by CABA, and CABA followed by one NHA. The cumulative monthly OS rates in each group were determined using a weighted-average approach. Results: Thirteen retrospective studies including 1016 patients who received NHA/NHA (469), NHA/CABA (318) or CABA/NHA (229) were evaluated. The 12-month OS rates were 28.5%, 61.3%, and 76.4%, respectively. There were no statistically significant differences in terms of known prognostic factors. Conclusions: Although the retrospective nature of the studies and potential selection biases, our data seem to confirm the potential cumulative survival benefit of using the NAs sequentially after docetaxel. There was no clear superiority of any one of the three strategies, but a sequence that includes CABA seems to suggest a possible OS advantage.