Beyond Frontline Therapy with Abiraterone and Enzalutamide in Metastatic Castration-Resistant Prostate Cancer: A Real-World US Study

This US retrospective study described treatment outcomes among patients with castration resistant prostate cancer receiving docetaxel following next generation hormonal agents in the metastatic setting from 2013-2019 (N = 5,213). Treatment duration with docetaxel in second/third-line was short ( similar to 4 months), and most patients died within one year. Results highlight a significant unmet need and serve as a benchmark for future studies. Background: Real-world evidence suggest that next generation hormonal agents (NHAs) abiraterone and enzalutamide were preferred as first-line (1L) therapies for metastatic castration-resistant prostate cancer (mCRPC) in the United States (US) pre-2020, with chemotherapies, particularly docetaxel, being preferred in subsequent lines (2L + ). This real-world study described patient characteristics, treatment patterns, time on treatment (ToT) and overall survival (OS) among patients with mCRPC treated with 2L and 3L docetaxel post-NHAs in the mCRPC setting. Methods: Adults with confirmed adenocarcinoma mCRPC diagnosis and >= 1 month of follow-up post-diagnosis were selected from a US electronic health record-derived oncology de-identified database (01/2013-03/2019). Based on the observed line of therapy sequences post-mCRPC diagnosis, patients who received NHA therapy in 1L and docetaxel therapy in 2L were included in the 2L docetaxel cohort, and patients who received NHA therapy in both 1L and 2L and docetaxel therapy in 3L were included in the 3L docetaxel cohort. ToT and OS were evaluated using Kaplan-Meier analysis. Results: Among 5,213 patients with mCRPC, 278 and 166 were included in the 2L and the 3L docetaxel cohorts, respectively (median age: 73 years for both cohorts). ADT was the most used class of medication pre-mCRPC ( > 75%). For the 2L cohort, the most common sequence post-mCRPC was 1L abiraterone -> 2L docetaxel (52.5%), while the median ToT and OS post-2L start were 4.1 and 10.5 months, respectively; for the 3L cohort, the most common sequence post-mCRPC was 1L abiraterone -> 2L enzalutamide -> 3L docetaxel (67.5%), while the median ToT and OS post-3L start were 3.8 and 8.7 months, respectively. Conclusions: This real-world study provides novel data on patients treated with docetaxel post-NHAs in a mCRPC setting and highlights the critical unmet need for developing more effective treatment options in this population.