Pfizer and Astellas Pharma US announced final overall survival (OS) results from the Phase 3 EMBARK study evaluating XTANDI (enzalutamide), in combination with leuprolide and as monotherapy, in men with non-metastatic hormone-sensitive prostate cancer (nmHSPC) with biochemical recurrence (BCR) at high risk for metastasis.

For the key secondary endpoint of OS, XTANDI plus leuprolide reduced the risk of death by 40.3% compared to leuprolide alone, making this the first and only androgen receptor inhibitor-based regimen to demonstrate an OS benefit in nmHSPC with high-risk BCR.

“These results highlight the central role of enzalutamide in extending survival for men with conventional imaging negative HSPC with high-risk BCR,” said Stephen J. Freedland, Director of the Center for Integrated Research in Cancer and Lifestyle at Cedars-Sinai and Associate Director for Training and Education at the Samuel Oschin Comprehensive Cancer Institute. “These data reinforce the benefits of earlier treatment initiation with enzalutamide.”

The median follow up time was 94.2 months for XTANDI in combination with leuprolide, 94 months for leuprolide only, and 93.8 months in the monotherapy XTANDI group.

The safety profile of XTANDI was consistent with that observed at the primary EMBARK analysis, and no new safety signals were identified. The most common adverse events (occurring in ≥10% of patients) in the XTANDI combination group were hot flashes and fatigue. The most common adverse events in the XTANDI monotherapy group were gynecomastia, hot flashes, and fatigue.

"With up to 90 percent of men with high-risk BCR developing metastatic disease, early intervention with effective therapy is critical,”3 said Johanna Bendell, Chief Development Officer, Oncology, Pfizer. “The final analysis from EMBARK shows that XTANDI plus leuprolide improved outcomes and extended lives for men facing high-risk BCR after local therapy with curative intent.”

Among men who have undergone definitive prostate cancer treatment, including radical prostatectomy, radiotherapy or both, an estimated 20-40% will experience BCR within 10 years.4 About nine out of 10 men with high-risk BCR will develop metastatic disease, and one in three will die as a result of their metastatic prostate cancer.

“This marks the eighth publication of XTANDI data in The New England Journal of Medicine, further demonstrating XTANDI’s profound impact on clinical outcomes in men with certain types of advanced prostate cancer,” said Shontelle Dodson, Executive Vice President, Head of Medical Affairs, Astellas. “These findings reinforce XTANDI’s position as a cornerstone therapy in the proactive management of these patients.”