NEW YORK & TOKYO — Pfizer and Astellas have reported positive results from a Phase 3 clinical trial showing that XTANDI (enzalutamide), when combined with leuprolide, significantly improves overall survival in men with non-metastatic hormone-sensitive prostate cancer (nmHSPC) who have a high risk of recurrence after initial treatment.
The findings come from the EMBARK study, which evaluated XTANDI in patients experiencing biochemical recurrence (BCR)—a rise in prostate-specific antigen (PSA) levels despite no visible signs of cancer spread. These patients had previously undergone surgery, radiation, or both with curative intent.
The combination of XTANDI and leuprolide achieved a statistically significant and clinically meaningful improvement in overall survival compared to leuprolide with placebo. XTANDI used as a standalone treatment also showed a positive trend, though it did not reach statistical significance.
“These data demonstrate that XTANDI can extend life for men with high-risk BCR,” said Dr. Neal Shore of the Carolina Urologic Research Center. “It supports the practice of early intervention in this patient population.”
The EMBARK study builds on earlier data showing that the XTANDI-leuprolide combination delayed disease progression. Those earlier results, published in The New England Journal of Medicine in 2023, had established the treatment’s benefit in extending metastasis-free survival (MFS).
No new safety concerns emerged in the latest analysis. Common side effects in the combination group included hot flashes and fatigue, while XTANDI alone was associated with gynecomastia, hot flashes, and fatigue.
XTANDI is currently approved in more than 80 countries and has been used by over 1.5 million men worldwide since its approval in 2012. The drug is already approved for use in various stages of prostate cancer, including metastatic and castration-resistant forms.
Pfizer and Astellas said full results from the EMBARK trial will be shared at an upcoming scientific meeting.
