New Reference: Long-Term Results of Enzalutamide for Metastatic Castration-Sensitive Prostate Cancer

This long-term analysis of randomized phase 3 trial of enzalutamide compared to a non-steroidal anti-androgen (NSAA) when added to testosterone suppression for metastatic hormone-sensitive prostate cancer confirmed that enzalutamide significantly prolonged overall survival, clinical progression-free survival, and prostate-specific antigen progression-free survival at 8 years. The long-term tolerability of enzalutamide was supported by a high proportion of patients remaining on treatment without dose reduction and no new safety signals were observed.

Study

Randomized, open-label, international, phase 3 trial [ENZAMET; ANZUP 1304, NCT02446405]

Metastatic, hormone-sensitive prostate cancer (mHSPC)

Testosterone suppression + enzalutamide (n=563) vs Testosterone suppression + non-steroidal anti-androgen (NSAA) (n=562)

Efficacy

mOS: 7.9 yrs vs 5.8 yrs (Enzalutamide vs. NSAA) (HR 0.73 [0.63-0.86])

8-yr OS: 50% vs 40%

8-yr Clinical PFS: 43% vs 20% (HR 0.49 [0.42-0.57])

8-yr PSA-PFS: 40% vs 19% (HR 0.48 [0.41-0.55])

8-yr Prostate-cancer-specific survival (PCSS): 61% vs 50%

Safety

Grade >=3 AE: cardiac disorders (2.2% vs 2.2%), nervous system disorders (2.3% vs 2.0%), falls (0.70% vs 0.24%), cerebrovascular and cardiac disorders (2.6% vs 2.5%), fatigue (1.4% vs 0.24%), fractures (1.3% vs 0.72%), cognitive impairment (0.07% vs 0.06%)