(UroToday.com) The 2025 American Society of Clinical Oncology (ASCO) Annual Meeting held in Chicago, IL between May 30th and June 3rd, 2025, was host to a prostate, testicular, and penile cancers poster session. Dr. Zeynep Ozay presented the results of a comparative analysis of the effectiveness of cabazitaxel versus 177Lu vipivotide tetraxetan in metastatic castrate-resistant prostate cancer (mCRPC).
Both cabazitaxel and Lu-177 are life-prolonging therapies for patients with mCRPC following progression on an androgen receptor pathway inhibitor (ARPI) and docetaxel. Herein, Dr. Ozay and colleagues sought to assess the real-world comparative effectiveness of cabazitaxel versus Lu-177 in mCRPC patients with disease progression following treatment with docetaxel and an ARPI.
Using the Flatiron Health electronic health record nationwide database, the study investigators included mCRPC patients with disease progression following docetaxel and an ARPI therapy who subsequently received single-agent cabazitaxel or Lu-177 therapy as the next line therapy. The primary study endpoints were real-world time to next therapy (rwTTNT) and overall survival (rwOS). The study endpoints were summarized using Kaplan-Meier survival curve estimates and compared in the context of propensity score (PS) matching weighted analysis using Cox proportional hazards modeling. The propensity score model included the following variables:
- Age
- Race/ethnicity
- Socioeconomic status
- Treatment year
- Gleason score
- ECOG performance status
- log2PSA
- Alkaline phosphatase (ALP) level
- Hemoglobin level
- Serum creatinine level
- Length of treatment
- Insurance status
- Practice type
Of the 24,105 metastatic prostate cancer patients identified in the Flatiron Health database, 1,445 were eligible and included (cabazitaxel: 1,227; Lu-177: 218). The baseline characteristics are summarized in the table below. The median patient age was 73–75 years. Patients in the Lu-177 arm were more likely to have received treatment in an academic practice (17.4% vs 15.9%, p=0.041). A slightly higher proportion of patients in the Lu-177 group had Gleason ≥8 disease (68.1% versus 66.9%; p=0.026).
Patients receiving Lu-177 had superior:
- rwTTNT: median, 8.3 vs 4.7 months (adjusted HR: 0.43, p<0.001)
- rwOS: median, 10.3 vs 8.8 months (adjusted HR: 0.61, p<0.001)
Dr. Ozay concluded that this is the largest real-world study showing significantly longer real-world time-to-next-therapy and overall survivals with Lu-177, compared to cabazitaxel in mCRPC patients pretreated with an ARPI and docetaxel. Notable limitations to this study include its retrospective nature, selection bias, data missingness, and lack of randomization.
Presented by: Zeynep Irem Ozay, MD, Postdoctoral Research Fellow, Huntsman Cancer Institute at the University of Utah, Salt Lake City, UT
Written by: Rashid K. Sayyid, MD, MSc – Robotic Urologic Oncology Fellow at The University of Southern California, @rksayyid on Twitter during the American Society of Clinical Oncology (ASCO) 2025 Annual Meeting, Chicago, IL, Fri, May 30 – Tues, Jun 3, 2025.
Related content: Lutetium-177 Outperforms Cabazitaxel in mCRPC: Real-World Flatiron Database Analysis - Zeynep Irem Ozay