Eight-year outcomes of testosterone suppression plus enzalutamide or a nonsteroidal antiandrogen for metastatic hormone-sensitive prostate cancer (ENZAMET; ANZUP 1304).
A Y Zhang, H Thomas, S Begbie et al.
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In 30 seconds
ENZAMET was a phase III, multicentre randomised trial comparing enzalutamide with a first-generation nonsteroidal antiandrogen (NSAA), each given with testosterone suppression, in participants with metastatic hormone-sensitive prostate cancer. At a median follow-up of 8.1 years, overall survival was longer with enzalutamide: median 7.9 versus 5.8 years, with 8-year survival of 50% versus 40% (hazard ratio 0.73, 95% CI 0.63-0.86, P = 0.0001). Clinical progression-free survival also favoured enzalutamide. Cardiac and nervous system grade 3-5 adverse-event rates were similar, while falls were more frequent with enzalutamide.
Key findings
- At 8 years, overall survival was 50% with enzalutamide versus 40% with NSAA (HR 0.73, 95% CI 0.63-0.86, P = 0.0001).
- Clinical PFS at 8 years was 43% versus 20%, favouring enzalutamide (HR 0.49, 95% CI 0.42-0.57, P < 0.0001).
- Prostate cancer deaths numbered 207 with enzalutamide and 261 with NSAA; deaths from other causes were similar (78 versus 76).
- Falls were more frequent with enzalutamide (0.70 versus 0.24 per 100 person-years); cardiac and nervous system grade 3-5 AE rates were similar.
Why it matters
These extended randomised-trial results show that the survival advantage of adding enzalutamide to testosterone suppression persisted over long follow-up in metastatic hormone-sensitive prostate cancer. The cause-of-death findings indicate that the difference was associated with fewer prostate cancer deaths, not an apparent reduction in deaths from other causes. The fall-rate difference is relevant when weighing long-term treatment harms.
What to keep in mind
Concurrent early docetaxel was permitted at clinician discretion, so treatment was not uniform across participants.