1642P - Integrated prognostic score in metastatic castration-resistant prostate cancer (mCRPC) treated with cabazitaxel: A CABASTY posthoc analysis

Background

Cabazitaxel (CBZ) is a standard in mCRPC patients (pts) who failed docetaxel (DOC) and an androgen receptor signalling inhibitor (ARSi). Primary results of CABASTY randomized trial comparing two CBZ schedules (triweekly 25mg/m² vs biweekly 16mg/m²) in mCRPC patients ≥ 65 y.o. have been published (Oudard, JAMA Oncol 2023). This posthoc analysis aimed to build and validate a prognostic score for mCRPC pts treated with CBZ.

Methods

A continuous integrated score was derived from multivariate Cox model hazard ratios (HR). We used graphical verification for calibration, C-index for discrimination and bootstrap for cross-validation of the model. The population was stratified into 3 groups using hierarchical Log-Rank optimization for score thresholds. We used CARD randomized trial (CBZ vs ARSi in mCRPC pts failing DOC and the alternative ARSi) database for external validation.

Results

Overall, 194 pts from CABASTY were included to derive our score (median age 75, 62% ECOG PS 1-2, 48% Gleason score of 8-10, 44% ≥2 metastatic sites, median PSA 67 ng/mL). Model variables included ECOG PS (0 vs 1-2), number of metastatic sites (

Conclusions

We developed and validated a prognostic score for mCRPC pts treated with cabazitaxel. Favorable group was benefiting from CBZ versus a second ARSi, but intermediate and poor prognostic groups did not. This score may help clinicians to identify pts requiring other treatment strategies.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

ARTIC.

Funding

Sanofi.

Disclosure

C. Thibault: Financial Interests, Personal, Advisory Board: Janssen, Astellas, Ipsen, Pfizer, Merck, MSD, BMS, AstraZeneca, AAA, Seagen; Financial Interests, Personal, Invited Speaker: Amgen; Financial Interests, Institutional, Funding: AstraZeneca, Sanofi; Financial Interests, Institutional, Research Grant: Janssen. S. Oudard: Financial Interests, Personal, Advisory Board, consultancy, advisory role: Sanofi; Financial Interests, Personal, Invited Speaker, public speaking and advisory role: Janssen; Financial Interests, Personal, Advisory Board, advisory role and public speaking: AstraZeneca, MSD, Merck, Astellas, Ipsen, Pfizer, Roche, Genentech; Financial Interests, Personal, Advisory Board, Advisory board and public speaking: BMS, Bayer, Novartis. E. Auclin: Financial Interests, Personal, Advisory Board: Amgen, Sanofi-Genzyme; Financial Interests, Personal, Other, travel expenses: Amgen. All other authors have declared no conflicts of interest.