The US Food and Drug Administration (FDA) has accepted for review the filing of a supplemental New Drug Application (sNDA) for Astellas and Pfizer’s Xtandi (enzalutamide), the companies have announced.

The filing is to add an indication for the treatment of men with metastatic hormone-sensitive prostate cancer (mHSPC), and has also been granted Priority Review, a designation given to those applications for drugs that, if approved, may offer significant improvements in the safety or effectiveness of the treatment, diagnosis or prevention of serious conditions when compared to standard applications.

Back in February, the companies revealed results from the Phase III ARCHES trial in men with mHSPC, which showed that the drug significantly improved radiographic progression-free survival, paving the way for the application to expand the drug's use.

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

Additionally, the sNDA submission is supported by data from ENZAMET, an Astellas-supported, investigator-sponsored Phase III research study which met its primary endpoint of overall survival (OS).

Pfizer is “pleased to receive the Priority Review designation, which reflects the need for more treatment options for men living with metastatic hormone-sensitive prostate cancer,” said Chris Boshoff, chief development officer, Oncology.

He continued, “The submission is supported by a strong data package, including two Phase III trials investigating XTANDI in men living with this form of prostate cancer.”

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.