- Astellas Pharma Inc. (TSE: 4503, President and CEO: Naoki Okamura, "Astellas") and Pfizer Inc. (NYSE: PFE) today announced that the companies received an approval by the U.S. Food and Drug Administration (FDA) of a supplemental New Drug Application for XTANDI® (enzalutamide), following FDA expedited development and review programs (Priority Review designation, Fast Track designation, Real-time Oncology Review), based on results from the Phase 3 EMBARK trial. With this approval, XTANDI becomes the first and only androgen receptor signaling inhibitor approved by the FDA for the treatment of patients with nonmetastatic castration-sensitive prostate cancer (nmCSPC) with biochemical recurrence at high risk for metastasis (high-risk BCR). Patients with nmCSPC with high-risk BCR may be treated with XTANDI with or without a gonadotropin-releasing hormone (GnRH) analog therapy.
Of men who have undergone definitive prostate cancer treatment, including radical prostatectomy, radiotherapy, or both, an estimated 20-40% will experience biochemical recurrence (BCR) within 10 years.1 About nine out of 10 men with high-risk BCR will develop metastatic disease, and one in three will die as a result of their metastatic prostate cancer.2
"For patients who were previously treated for prostate cancer and had achieved remission, only to later receive the distressing news of disease recurrence with a risk of metastasis, the emotional toll can be profound," said Courtney Bugler, President and CEO of ZERO Prostate Cancer. "This approval of XTANDI is a promising treatment option for the community, offering a ray of hope to patients and their caregivers during these challenging times."
"Having had the privilege of taking care of patients with prostate cancer for nearly 40 years, I have been fortunate to have participated in many of the prostate cancer landscape changing trials; notably, we have not progressed our evidenced-based care for patients with biochemical recurrence (BCR), also known as nmCSPC, until the completion of the EMBARK trial," said Neal Shore, MD, FACS, Chief Medical Officer of Strategic Innovation and Pharmacy, GenesisCare USA, Director, CPI, Carolina Urologic Research Center, and Primary Investigator for the EMBARK trial. "Previously, treatment options for these BCR patients, especially those who have a high likelihood of developing metastases were limited. The FDA approval of XTANDI for patients with nmCSPC with BCR at high risk of metastasis represents an important advancement whereby an androgen deprivation signaling inhibitor, enzalutamide, has achieved standard of care discussion for patient-physician decision-making."
The approval is based on results from the Phase 3 EMBARK trial, which evaluated XTANDI plus leuprolide, placebo plus leuprolide, and XTANDI (single agent) in patients with nonmetastatic hormone- (or castration-) sensitive prostate cancer (nmHSPC or nmCSPC) with high-risk BCR. Detailed results from the trial were presented as a plenary session during the 2023 American Urological Association Annual Meeting and subsequently published in the New England Journal of Medicine.
"Today's FDA approval is the culmination of over a decade of research and development as we've worked to bring XTANDI forward for as many patients with prostate cancer as possible who may benefit," said Ahsan Arozullah, M.D., MPH, Senior Vice President and Head of Oncology Development, Astellas. "With every milestone, our clinical development program has played an instrumental role in changing the course of patients' lives. We are proud that XTANDI can now be offered to a subset of men with nonmetastatic castration-sensitive prostate cancer with biochemical recurrence and at high risk for metastases."
"More than 300,000 men in the U.S. have been prescribed XTANDI, and we are excited to have this approval expand the indication for the first time into an earlier setting of the disease," said Chris Boshoff, M.D., Ph.D., Chief Oncology Research and Development Officer and Executive Vice President at Pfizer. "This milestone is a testament to XTANDI's legacy and robust clinical profile, with overall survival demonstrated for patients with metastatic castration-resistant prostate cancer, nonmetastatic castration-resistant prostate cancer, and metastatic castration-sensitive prostate cancer. With today's approval, we look forward to bringing this therapy to even more patients who have nonmetastatic castration-sensitive prostate cancer at high risk for their cancer metastasizing."
XTANDI is currently under review with other regulatory authorities around the world, including the European Medicines Agency, to support an expanded indication in nmHSPC (or nmCSPC) with high-risk BCR based on the results of EMBARK.
About EMBARK
The Astellas- and Pfizer-led Phase 3, randomized, double-blind, placebo-controlled, multi-national trial enrolled 1,068 patients with nonmetastatic hormone- (or castration-) sensitive prostate cancer (nmHSPC or nmCSPC) with high-risk BCR at sites in the U.S., Canada, Europe, South America, and the Asia-Pacific region. Patients who were considered to experience high-risk BCR had a prostate-specific antigen doubling time (PSA-DT) ≤ 9 months; serum testosterone ≥ 150 ng/dL (5.2 nmol/L); and screening PSA by the central laboratory ≥ 1 ng/mL if they had a radical prostatectomy (with or without radiotherapy) as primary treatment for prostate cancer, or at least 2 ng/mL above the nadir if they had radiotherapy only as primary treatment for prostate cancer. Patients in the EMBARK trial were randomized to receive enzalutamide 160 mg daily plus leuprolide (n=355), enzalutamide 160 mg as a single agent (n=355), or placebo plus leuprolide (n=358). Leuprolide 22.5 mg was administered every 12 weeks.
EMBARK met its primary endpoint of metastasis-free survival (MFS) for the XTANDI plus leuprolide arm, demonstrating a statistically significant reduction in the risk of metastasis or death over placebo plus leuprolide. MFS is defined as the duration of time in months between randomization and the earliest objective evidence of radiographic progression by central imaging or death due to any cause, whichever occurred first.
The study also met a key secondary endpoint, by demonstrating that patients treated with XTANDI (single agent) had a statistically significant reduction in the risk of metastasis or death versus placebo plus leuprolide, meeting its MFS endpoint.
In EMBARK, Grade 3 or higher adverse events (AEs) were reported in 46% of XTANDI plus leuprolide patients, 50% of patients treated with XTANDI (single agent), and 43% of patients receiving placebo plus leuprolide. Permanent discontinuation due to AEs as the primary reason was reported in 21% of XTANDI plus leuprolide patients, 18% in XTANDI (single agent) patients, and 10% in placebo plus leuprolide patients.
