FDA approves Xtandi for metastatic castration-sensitive prostate cancer
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The FDA approved enzalutamide for the treatment of metastatic castration-sensitive prostate cancer.
Enzalutamide (Xtandi; Pfizer, Astellas) already had been approved for men with nonmetastatic and metastatic castration-resistant prostate cancer.
The FDA based the new indication on results of the randomized phase 3 ARCHES study, which included 1,150 men with metastatic castration-sensitive prostate cancer treated at sites in the United States, Canada, Europe, South America and the Asia-Pacific region.
In the double-blind, multinational study, researchers randomly assigned men to 160 mg enzalutamide daily or placebo. Men continued on a luteinizing hormone-releasing hormone agonist or antagonist or had a history of bilateral orchiectomy.
The study met its primary endpoint, as results showed the use of enzalutamide plus androgen deprivation therapy significantly reduced risk for radiographic progression or death as determined by blinded central review compared with placebo plus ADT (HR = 0.39; 95% CI, 0.3-0.5).
“Men with metastatic castration-sensitive prostate cancer face complex treatment decisions, and it is critical for physicians and patients to have as much information as possible when deciding on all of the options available,” researcher Andrew Armstrong, MD, professor of medicine, surgery, pharmacology and cancer biology, as well as director of research at Duke Cancer Institute's Center for Prostate and Urologic Cancers, said in a press release. “The research supporting the FDA approval and updated treatment guidelines provide physicians and patients with compelling evidence to consider enzalutamide as a treatment option for men with this disease.”
OS data from the ARCHES study were not mature at the time of final radiographic PFS analysis.
Enzalutamide exhibited a safety profile generally consistent with that observed in prior trials. The most common adverse reactions that occurred more frequently among enzalutamide-treated patients included hot flushes (27% vs. 22%), asthenic conditions (24% vs. 20%), hypertension (8% vs. 5.6%), fractures (6.5% vs. 4.2%) and musculoskeletal pain (6.3% vs. 4%).
“[This] 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 the release. “The FDA approval marks continued progress to help meet the needs of patients, including men living with metastatic castration-sensitive prostate cancer.”