Efficacy of cabazitaxel and its relationship with predictors of poor response to second hormonal therapies (2d HT) in metastatic castration-resistant prostate cancer (mCRPC).

Abstract

137 Background: Potential predictors of low response to 2d HT including new agents have been recently identified: high Gleason score, rapid progression with first androgen deprivation therapy (ADT), chemotherapy lines >1 and low baseline testosterone (T) levels. We evaluated the influence of these factors on the efficacy of cabazitaxel (C), a new taxane developed to overcome docetaxel (D) resistance. Methods: Records of 84 consecutive mCRPC pts (median 67 yrs) treated with C for disease progression on D or after D were retrospectively collected in 8 French centers. Baseline characteristics, disease history, PSA response, overall survival (OS) and radiological or clinical progression-free survival (PFS) were collected. Results: At C initiation, 84% of pts were ECOG 0-1, 59% had pain and 24% received ≥2 prior chemotherapy lines. Metastases were located in bone (93%), lymph nodes (49%) and visceral/soft tissues (9%). Gleason score was 8-10 in 47%, median time to progression with first ADT was 20 months and median T was 0.1 ng/ml. Median number of C cycles received was 6 (range 2-14). Efficacy of C was not influenced by Gleason score, response duration to first ADT, prior number of chemo lines, or baseline T (table). Main grade ≥ 3 toxicities were neutropenia (32%), anaemia (17%), thrombocytopenia (8%), diarrhoea (6%), and febrile neutropenia (5%). There was no grade ≥3 peripheral neuropathy and no toxic death. Conclusions: This retrospective study suggests that C is effective and shows an acceptable safety profile. Efficacy was not influenced by predictors of poor response to 2d HT (high Gleason, short response to first ADT, Number of chemo lines, low T levels). If these results are confirmed in further investigations, cabazitaxel could be proposed whatever the baseline characteristics of mCRPC pts. [Table: see text]