Pfizer and Astellas have announced results from the Phase III ARCHES trial in men with metastatic hormone-sensitive prostate cancer (HSPC), showing that Xtandi (enzalutamide) significantly improved radiographic progression-free survival, paving the way for an application to expand the drug's use.

The results, which are for the drug in combination with androgen deprivation therapy, show a significant reduction in the risk of radiographic progression or death by 61%, thus meeting the trial's primary endpoint.

The companies say they intend to discuss the data with global health authorities to potentially support a new indication for XTANDI in men with mHSPC.

“The ARCHES trial demonstrated that Xtandi plus standard hormonal therapy delayed disease progression, and if approved, has the potential to be an important treatment option for men with prostate cancer that has spread but has not yet become hormone resistant,” said Andrew Armstrong, Professor of Medicine, Surgery, Pharmacology and Cancer Biology, and director of research in the Duke Cancer Institute’s Center for Prostate and Urologic Cancers.

In men with prostate cancer, the disease is considered metastatic once the cancer has spread outside of the prostate gland to other parts of the body, such as the bones, lymph nodes, bladder and rectum, with approximately 38,000 men in the US developing metastatic HSPC every year.

Xtandi is currently approved in the US and Japan for the treatment of castration-resistant prostate cancer (CRPC) and in the EU for advanced and high-risk non-metastatic CRPC.