Prognostic parameters for response to enzalutamide after docetaxel and abiraterone treatment in metastatic castration-resistant prostate cancer patients; a possible time relation

Item does not contain fulltextBACKGROUND: Abiraterone Acetate (AA) and Enzalutamide (Enz) are effective hormonal treatments in mCRPC patients. Retrospective studies suggested clinical cross-resistance between Enz and AA. However, 12.8-39.1% of patients previously treated with docetaxel (Doc) and AA do respond to Enz. These responders have not been characterized. METHODS: 102 Enz treated mCRPC patients after AA and Doc treatment were included in this study. Differences in patient characteristics and previous treatment outcomes between PSA responders and non-responders on Enz were evaluated. RESULTS: Median Progression-Free Survival was 12.2 weeks (95%CI 11.7-14.3) and Overall Survival 43.5 weeks (95%CI 37.4-61.2). There were 26 (25%) Enz-responders and 76 (75%) non-responders. Significant higher percentages of Gleason scores >/=8 and PSA doubling times (PSA-DT) /=40 (68 patients) revealed significant differences in baseline PSA levels, PSA-DT /=8 and IAE's between Enz responders and non-responders. CONCLUSIONS: PSA response to Enz after previous AA and Doc treatment was associated with a longer IAE, a higher Gleason score and a PSA-DT