Outcomes of metastatic castration-resistant prostate cancer (mCRPC) patients (pts) treated with different new agents (NAs) sequence in post-docetaxel (DOC) setting: Final analysis from a multicenter Italian study.

Abstract

5030 Background: Abiraterone acetate (AA), cabazitaxel (CABA), and enzalutamide (ENZ) may prolong survival in mCRPC pts progressing after DOC, although it is not clear how to use NAs to best exploit their efficacy and avoiding their possible cross resistances. In 2015, we reported the outcomes of a series of 260 mCRPC pts, receiving at least 2 NAs, after DOC progression in routine clinical practice (Eur Urol. 2015;68:147-53). In the present study we updated the analysis with longer follow-up and by assessing a larger series of pts. Methods: Based on a multi-institutional collaboration, we collected data of pts who received at least 2 NAs after DOC: we assessed biochemical (bRR) and objective response rates (oRR) and progression free survival (PFS) of each NA by treatment line; moreover, we evaluated the overall survival (OS) from the second line start by sequence strategy. For the OS analysis we differentiated three different types of NAs sequences after DOC: one new hormone agent (AA or ENZ) followed by CABA (NHA→CABA); CABA followed by AA or ENZ (CABA →NHA); one NHA followed by the other NHA (NHA →NHA). Results: A consecutive series of 476 mCRPC pts with bone (86%), nodal (56%) or visceral (15%) mets, was collected. All received NAs as 2nd and 3rdline after DOC. The outcomes by both treatment lines and NAs are detailed in the table. We observed a statistically significant difference in terms of OS when compared the three sequence strategies: the median OS of pts treated with NHA→CABA, CABA→NHA, and NHA→NHA was respectively 12.9 mos, 14.2 mos, and 8.8 mos, respectively (p = 0.01). Conclusions: At our knowledge this retrospective study reports the highest number of pts treated post-DOC with at least 2 NAs. Our data confirmed that the activity of NAs decreased in the 3rd line compared to the 2nd line and suggested a cumulative OS advantage when CABA is used in the sequence. [Table: see text]