Pfizer and Astellas Pharma announced positive topline results from the overall survival analysis of 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 patients treated with Xtandi plus leuprolide versus placebo plus leuprolide, the study met the key secondary endpoint, showing a statistically significant and clinically meaningful improvement in OS. Xtandi monotherapy showed a favorable trend toward improved OS, but the difference was not statistically significant. No new safety signals were observed, and the safety results were consistent with Xtandi’s known profile.

“These data show that Xtandi can extend life for men with nmHSPC and high-risk BCR who relapsed after initial curative-intent treatment,” said Neal Shore, M.D., START Carolinas/Carolina Urologic Research Center.

Among men who have undergone prostate cancer treatment, 20-40% experience BCR within 10 years. About 90% of men with high-risk BCR develop metastatic disease, and one-third may die as a result.

“Xtandi is the only androgen receptor inhibitor-based regimen with demonstrated survival benefit in metastatic HSPC and nmHSPC with high-risk BCR, as well as castration-resistant prostate cancer,” said Johanna Bendell, M.D., Oncology Chief Development Officer, Pfizer.

In the EMBARK study, patients were randomized to Xtandi plus leuprolide, placebo plus leuprolide, or Xtandi monotherapy. An earlier analysis published in The New England Journal of Medicine in 2023 showed the study met its primary endpoint, with a significant improvement in metastasis-free survival (MFS) for Xtandi plus leuprolide.

Xtandi is approved in over 80 countries, including the U.S., EU, and Japan.

“More than 1.5 million men with advanced prostate cancer have been treated with Xtandi since its approval in 2012,” said Shontelle Dodson, Executive Vice President, Astellas.

“The EMBARK trial reflects Astellas’ and Pfizer’s commitment to prostate cancer treatment. Full OS results will be presented at an upcoming medical meeting.”