Pfizer and Astellas' Xtandi Wins FDA Approval for New Prostate Cancer Indication

Prostate Cancer

Xtandi, the prostate cancer drug developed by Pfizer and Japan-based Astellas, won approval for a new indication as a treatment for patients with metastatic castration-sensitive prostate cancer (mCSPC).

On Monday, the U.S. Food and Drug Administration (FDA) greenlit the new indications for Xtandi (enzalutamide). With the latest approval, Xtandi, an androgen receptor inhibitor, is now the only oral treatment approved by the FDA for three distinct types of advanced prostate cancer – non-metastatic and metastatic castration-resistant prostate cancer (CRPC) and mCSPC. Xtandi won approval for non-metastatic Castration-Resistant Prostate Cancer last year. Xtandi was initially approved in 2012 for late-stage prostate cancer.

Prostate cancer is the second most common cancer in men worldwide, with about 164,000 expected diagnoses in the United States this year. It is estimated that more than 40,000 men in the United States are living with mCSPC, a form of prostate cancer that has spread to other parts of the body and still responds to a medical or surgical treatment that lowers testosterone, the companies said in the announcement.  Men are considered hormone (or castration) sensitive if their disease still responds to medical or surgical treatment to lower testosterone levels.

Xtandi’s latest approval was based on the Phase III ARCHES study. Results from the late-stage study showed that Xtandi plus androgen deprivation therapy (ADT) significantly reduced the risk of radiographic progression or death by 61% versus ADT alone. Secondary endpoints in the ARCHES study showed that XTANDI plus ADT reduced the risk of PSA progression and reduced the risk of starting a new antineoplastic therapy compared to ADT alone. Overall survival data were not mature at the time of final radiographic progression-free survival analysis, the companies said.

Andrew Armstrong, director of research in the Duke Cancer Institute's Center for Prostate and Urologic Cancers and lead investigator of the ARCHES study, said that men with metastatic castration-sensitive prostate cancer face complex treatment decisions. Treating physicians need to be as informed as possible about their options, he said. Armstrong noted that with the ARCHES data, as well as updated FDA treatment guidelines, physicians and patients have “compelling evidence to consider enzalutamide as a treatment option for men with this disease,” he said.

The safety of Xtandi remained consistent with previous trials.

Andrew Krivoshik, oncology therapeutic head at Astellas, said Xtandi has been established as a standard of care for men with castration-resistant prostate cancer. The latest approval in metastatic castration-sensitive prostate cancer means physicians can now offer Xtandi to men earlier in their advanced prostate cancer treatment journey, Krivoshik said in a statement.

“Today's approval adds to over a decade of global clinical research aimed at better understanding the potential benefit of Xtandi for men with advanced prostate cancer,” Andy Schmeltz, global president of Pfizer Oncology said in a statement. “The FDA approval marks continued progress to help meet the needs of patients, including men living with metastatic castration-sensitive prostate cancer.”

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