Adding Pfizer and Astellas Pharma’s Xtandi to hormone therapy significantly cut the risk of prostate cancer spreading compared to hormone therapy alone, trial findings show.

According to results from the Phase III PROSPER trial, Xtandi (enzalutamide) plus androgen deprivation therapy (ADT) slashed the risk of developing metastases or death by 71 percent compared to ADT alone in patients with non-metastatic Castration-Resistant Prostate Cancer (CRPC).

The median for the primary endpoint, metastasis-free survival (MFS), was 36.6 months for men who received Xtandi compared to 14.7 months with ADT alone.

Data from the trial also showed that patients who received Xtandi/ADT had a 93 percent reduction in relative risk of PSA progression, and prolonged the median time to first use of new antineoplastic therapy by 21.9 months, compared to ADT alone.

“In patients with non-metastatic CRPC, there is a high unmet need to delay development of metastases and the progression to advanced prostate cancer. There are currently no approved systemic therapies for patients with non-metastatic CRPC in the US,” said Maha Hussain, Robert H. Lurie Comprehensive Cancer Center of Northwestern University, who will present the data at a medical congress later this year.

“In the PROSPER trial, treatment with enzalutamide plus ADT delayed the development of metastases compared to standard of care ADT alone and, if approved, may provide men with non-metastatic CRPC an important new treatment option.”

The companies noted that marketing applications based on the results of the PROSPER study have already been submitted to the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA), and are now being considered for full review.