Tombal B, et al. - Taking into account a large series of patients and an important follow-up period, analysts demonstrated enzalutamide anti-tumor activity was maintained in patients with hormone-naïve prostate cancer at 3 years. Overall, bone mineral density, global health status and safety results were similar to those at 2 years.

Methods

• In this study, 67 patients with hormone-naïve prostate cancer and non-castrate testosterone (≥230 ng/dL) received enzalutamide 160 mg/day orally until disease progression or unacceptable toxicity in a single-arm analysis.
• The preliminary outcome was prostate-specific antigen response (≥80% decline from baseline).

Results

• In this analysis, no patients discontinued treatment during year 3.
• 38 (90.5%; 95% confidence interval 77.4, 97.3) maintained a prostate-specific antigen response out of 42 patients with prostate-specific antigen assessments at 3 years.
• 17 (65.4%) had complete or partial response as the best overall response over 3 years out of 26 patients with metastases at baseline.
• In patients who completed the 3-year visit, they found minimal mean changes from baseline in total body bone mineral density or bone mineral density of the femoral neck, trochanter, spine L1–L4 or forearm (range, -2.7% to -0.1%).
• They found that total body fat increased (mean, 16.5%), total lean body mass decreased (mean, -6.5%) and global health status minimally decreased from baseline at 3 years.
• The data showed that common adverse events were gynecomastia, fatigue, hot flush and nipple pain.