Outcomes of post-progression therapies in patients (pts) with metastatic castration-sensitive prostate cancer (mCSPC) progressing after docetaxel (DOC): Real-world data from an Italian multicenter observational study (ECHOS trial)

Background: The introduction of DOC in mCSPC raises the issue concerning the best therapeutic strategy after pts’ progression. Different options are available: a switch strategy with an androgen receptor signaling inhibitor (ARSI), an alternative chemotherapy-based strategy based on cabazitaxel (CABA), or a re-challenge strategy by using DOC again. In this view, it could be of interest to describe the outcomes of post-progression strategies adopted in the real-world. From 2014, ECHOS multicenter study is collecting real world data from mCSPC pts in Italy. Here, we present post-progression preliminary findings of 568 pts treated with DOC and enrolled in the study within 31 December 2021. Methods: We reviewed the clinical records of the mCSPC pts treated with DOC in 34 Italian Institutions. For each pt we recorded pre- and post-DOC clinical history, baseline characteristics, treatment details and clinical outcomes. Results: Among the 568 pts, after a median follow-up of 22 mos, 389 pts experienced disease progression and 227 died. The progression occurred after a median of 10.4 mos (range 0.3-62.1). Among the progressed pts, 47 did not received further active treatment, while 342 received at least one systemic treatment after progression. The most frequent post-progression treatment was ARSI (73.1%), followed by CABA (19%), combination of ARSI and PARP inhibitors within clinical trials (2.6%), DOC re-challenge (2.1%), platinum-based chemotherapy (1.8%), and radium 223 (0.9%). The outcomes of the first-line agents and the number of subsequent administered life-prolonging agents (LPA) are described. The length of disease control obtained with DOC influenced the duration of first post-progression therapy: in pts who progressed after DOC within 10.4 mos, the duration was significantly shorter than in pts with later disease progression (5.9 mos vs 9.8 mos, p < 0.0001). Noteworthy, pts with more aggressive disease leading to a faster progression received more frequently CABA than ARSI: disease progression after DOC in CABA group and in ARSI group occurred with a median of 9.1 mos and 13.2 mos, respectively (p = 0.002). Conclusions: This is one of the largest real-world report on the outcomes of first post-progression therapies after DOC in mCSPC pts. We showed that ARSI-based therapy is the most common strategy adopted after DOC progression. Our findings suggested a different first post-progression strategy according to the time of post-DOC progression onset.