Optimal therapy after docetaxel and an androgen receptor pathway inhibitor (ARPI) in metastatic castration-resistant prostate cancer (mCRPC) remains debated. We aimed to build and validate the cabascore, a prognostic and predictive score for patients with mCRPC receiving cabazitaxel, to guide treatment strategy.
In this post hoc analysis of the randomized CABASTY trial, the cabascore was derived from multivariable Cox model hazard ratios for overall survival (OS). The population was stratified into three groups using log-rank optimization for score thresholds. Data from the phase 3 CARD and PROSELICA clinical trials were used for validation.
A total of 194 patients from CABASTY were included. Model variables were baseline Eastern Cooperative Oncology Group performance status (0 versus 1-2), metastatic sites (<2 vs ≥2), prostate-specific antigen, lactate dehydrogenase, alkaline phosphatase, and hemoglobin. Median OS was 21.6, 12.5, and 6.2 mo for cabascore-determined favorable, intermediate, and poor prognostic subgroups, respectively (intermediate versus favorable: hazard ratio (HR) = 2.14; 95% confidence interval (CI) = 1.41-3.25; p < 0.001; poor versus favorable: HR = 5.41; 95% CI = 3.42-8.72; p < 0.001). Validation of the model in the PROSELICA (n = 1175) and CARD (n = 126) cabazitaxel-exposed populations confirmed significantly prolonged median OS in the favorable versus intermediate and poor groups (both comparisons p < 0.001). In the overall CARD population (n = 250), cabazitaxel improved OS versus ARPI in the favorable group (p = 0.003), but not in the intermediate or poor groups.
The cabascore may help tailor treatment strategy in patients with mCRPC. Exploratory analyses suggest a greater benefit of cabazitaxel in patients with a favorable prognosis versus a second-line ARPI.
ClinicalTrials.gov Identifiers: NCT02961257 (CABASTY), NCT01308580 (PROSELICA), NCT02485691 (CARD).
European urology oncology. 2026 Apr 21 [Epub ahead of print]
Charles Vauchier, Constance Thibault, Maud Velev, Ondine Becker, Zoé Guillaume, Elisabeth Ashton, Sonia Zaibet, Hugo Berthou, Félicie Courtinat, Claire Gervais, Adrien Rochand, Debbie Robbrecht, Stéphane Oudard, Edouard Auclin
Department of Medical Oncology, Hôpital Européen Georges Pompidou, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris, France; Université Paris Cité, Paris, France., Department of Medical Oncology, Hôpital Européen Georges Pompidou, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris, France., Erasmus MC Cancer Institute, Rotterdam, Netherlands., Department of Medical Oncology, Hôpital Européen Georges Pompidou, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris, France; Université Paris Cité, Paris, France. Electronic address: .