Pfizer Inc. and Astellas Pharma Inc. announced positive topline results from the overall survival (OS) analysis from the Phase 3 EMBARK study evaluating XTANDI® (enzalutamide), in combination with leuprolide and as a monotherapy, in men with non-metastatic hormone-sensitive prostate cancer with biochemical recurrence (BCR) at high risk for metastasis.
For patients treated with XTANDI plus leuprolide versus placebo plus leuprolide, EMBARK met the key secondary endpoint with a statistically significant and clinically meaningful improvement in OS. Results also showed a favorable trend towards improved OS for patients treated with XTANDI monotherapy versus placebo plus leuprolide, however the difference did not reach statistical significance. No new safety signals were observed in the analysis, and the safety results were consistent with the demonstrated safety profile of XTANDI.
“These data demonstrate that treatment with XTANDI can extend life for men with nmHSPC and high-risk BCR who have relapsed after initial curative-intent therapy with prostatectomy, radiation therapy or both, further validating EMBARK’s metastasis-free survival (MFS) data,” said Neal Shore, M.D., F.A.C.S, START Carolinas/Carolina Urologic Research Center. “While men with nmHSPC with high-risk BCR now have expanded treatment choices, these results demonstrate a clear clinical benefit, including both MFS and OS, supporting the clinical practice of initiating XTANDI for these patients.”
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. 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.3
“XTANDI is the only androgen receptor inhibitor-based regimen to demonstrate a survival benefit in metastatic HSPC and nmHSPC with high-risk BCR, as well as castration-resistant prostate cancer, highlighting its significant patient impact in advanced prostate cancer,” said Johanna Bendell, M.D., Oncology Chief Development Officer, Pfizer. “These positive results add to the robust clinical support for the use of XTANDI and broaden clinical confidence, offering men with high-risk BCR evidence that they might live longer when they start XTANDI early.”
In the EMBARK study, patients were randomized to one of three study arms: XTANDI plus leuprolide, placebo plus leuprolide, or XTANDI monotherapy. An initial analysis was previously reported in The New England Journal of Medicine in 2023, demonstrating that the study met its primary endpoint with a statistically significant and clinically meaningful improvement in MFS for patients treated with XTANDI plus leuprolide versus placebo plus leuprolide.
The most common adverse events (occurring in ≥10% of patients) in the combination group and the leuprolide-alone group were hot flashes and fatigue. The most common adverse events in the monotherapy group were gynecomastia, hot flashes, and fatigue.
XTANDI is currently approved in more than 80 countries, including in the United States, European Union, and Japan.
“Over 1.5 million men with advanced prostate cancer around the world have benefited from treatment with XTANDI since its initial approval in 2012,”5 said Shontelle Dodson, Executive Vice President, Head of Medical Affairs, Astellas. “The scope and rigor of the EMBARK trial exemplify Astellas’ and Pfizer’s longstanding commitment to the prostate cancer community, and we look forward to sharing detailed findings in a future scientific forum.”
