Third-line Enzalutamide Following Docetaxel and Abiraterone in Metastatic Castrate-resistant Prostate Cancer

Abstract

Background: There are no published randomised trials on the efficacy of enzalutamide against metastatic castrate-resistant prostate cancer (mCRPC) after docetaxel and abiraterone. We evaluated the activity of third-line enzalutamide in men with mCRPC after docetaxel and abiraterone.

Patients and methods: Progression-free (PFS) and overall (OS) survival from the start of enzalutamide were compared according to response to abiraterone in men with mCRPC treated at a single cancer centre.

Results: Median PFS and OS for the whole 34-patient cohort from starting enzalutamide were 2.7 months (95% confidence interval=1.4-4.0 months) and 10.4 months (95% confidence interval=9.0-11.7 months). There was no significant difference in PFS and OS in patients according to prostate-specific antigen response to abiraterone (≥50% vs. <50%, ≤ or >6 months).

Conclusion: In mCRPC, enzalutamide has modest activity after docetaxel and abiraterone. Response to previous abiraterone is not predictive of subsequent enzalutamide response.

Keywords: Metastatic; castrate-resistant; drug sequencing; enzalutamide; prostate cancer; third line.