Astellas and Pfizer Showcase Five-Year Survival Benefits of XTANDI in Metastatic Hormone-Sensitive Prostate Cancer at ASCO 2025
In a pivotal milestone for prostate cancer treatment, Astellas Pharma Inc. and Pfizer Inc. have announced compelling long-term survival data for XTANDI™ (enzalutamide), their androgen receptor pathway inhibitor (ARPI), in men diagnosed with metastatic hormone-sensitive prostate cancer (mHSPC). These findings, derived from an extended follow-up of the Phase 3 ARCHES trial, offer new hope for patients facing one of the most aggressive forms of prostate cancer and underscore XTANDI’s role as a cornerstone therapy in advanced disease management.
The updated data from ARCHES were disclosed in advance of a formal presentation scheduled for the American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago. The oral session, designated as Abstract #5005, will take place on Tuesday, June 3, between 9:45 a.m. and 12:45 p.m. Central Time. The presentation will provide insights from a five-year follow-up of patients treated with a combination of enzalutamide and androgen deprivation therapy (ADT) versus a placebo plus ADT regimen.
Landmark Survival Gains in mHSPC
According to the newly released findings, patients treated with XTANDI plus ADT experienced a 30% reduction in the risk of death compared to those who received standard hormonal therapy alone. More strikingly, two-thirds of men in the treatment group were still alive five years after initiating therapy—a figure that represents a 13% absolute and 30% relative improvement in survival rates over traditional approaches.
Dr. Andrew J. Armstrong, Director of Research at the Center for Prostate & Urologic Cancers at Duke Cancer Institute and the lead investigator for ARCHES, emphasized the paradigm shift these data represent in prostate cancer care. “Historically, the likelihood of survival at five years for men with metastatic hormone-sensitive prostate cancer was low, but with advancements in initial treatment intensification like what we’ve seen with XTANDI, this is now becoming the standard,” Armstrong said. “These results are clinically meaningful, particularly as they demonstrate benefits in both high and low disease burden populations.”
Subgroup Analyses Reinforce Broad Efficacy
The five-year update includes detailed subgroup analyses, offering a more nuanced picture of XTANDI’s clinical performance across different patient profiles:
- High-volume disease: Patients experienced a 36-month improvement in median overall survival (HR: 0.70; 95% CI: 0.56–0.88).
- Low-volume disease: A consistent benefit was observed, although the confidence interval slightly overlapped unity (HR: 0.71; 95% CI: 0.49–1.05).
- Previous docetaxel use: XTANDI plus ADT yielded a hazard ratio of 0.67 (95% CI: 0.43–1.05), indicating a favorable trend.
- No prior docetaxel therapy: Patients showed a statistically significant benefit (HR: 0.71; 95% CI: 0.57–0.88).
Importantly, the safety profile of enzalutamide remained consistent with earlier analyses of ARCHES, and no new treatment-emergent adverse events (TEAEs) were identified during the extended follow-up period. This stability in tolerability strengthens the case for XTANDI as a long-term treatment option.
Enduring Impact Across Treatment Continuum
Commenting on the broader implications of the ARCHES data, Shontelle Dodson, Executive Vice President and Head of Medical Affairs at Astellas, highlighted the cumulative evidence supporting XTANDI’s impact across the prostate cancer spectrum.
“The survival benefits of intervention with XTANDI in advanced prostate cancer are well-recognized,” Dodson said. “This growing body of clinical evidence continues to reinforce its long-term efficacy and real-world impact in prostate cancer, including the metastatic setting. XTANDI is demonstrably changing the trajectory for patients living with this disease.”
Pfizer’s Dr. Johanna Bendell, Oncology Chief Development Officer, echoed this sentiment. “Until recently, patients with metastatic hormone-sensitive prostate cancer faced a poor prognosis, particularly in advanced stages, often due to treatment resistance. As the only androgen receptor inhibitor demonstrating sustained five-year survival in this patient population, these data further reinforce XTANDI combined with ADT as the standard-of-care for treating this advanced disease.”
The companies confirmed that the complete five-year data set from the ARCHES trial will be submitted for publication in a peer-reviewed scientific journal to facilitate broader dissemination within the oncology community.
Complementary Evidence from ENZAMET: Eight-Year Outcomes Extend XTANDI’s Legacy
Further supporting XTANDI’s durability as a treatment for mHSPC, long-term data from the independent ENZAMET trial will also be presented at ASCO. This Phase 3 study, led by the Australian and New Zealand Urogenital and Prostate Cancer Trials Group (ANZUP) and sponsored by the University of Sydney, assessed the efficacy of enzalutamide versus a non-steroidal anti-androgen (NSAA), both in combination with testosterone suppression and with or without docetaxel.
Dr. Christopher Sweeney, primary investigator of the ENZAMET follow-up, shared that the median follow-up time reached an impressive 98 months—more than eight years. Patients in the XTANDI arm achieved a median overall survival of 8.0 years compared to 5.8 years for those in the NSAA group (HR: 0.73; 95% CI: 0.63–0.86). At the 96-month mark, survival rates were 50% for XTANDI and 40% for NSAA-treated patients.
Progression-free survival (PFS) data further underscored the strength of XTANDI, with a hazard ratio of 0.49 (95% CI: 0.42–0.57), favoring the ARPI-based approach. Notably, prostate cancer was the cause of 468 out of 622 total deaths recorded in the study, but the number of deaths was significantly lower in the XTANDI group (207) compared to the NSAA group (261).
The treatment duration was also markedly longer in the XTANDI group—58 months versus 36 months for NSAA—with 33% of patients still receiving enzalutamide at the end of the follow-up period. Among those, 88% remained on the full 160 mg dose, attesting to the treatment’s long-term tolerability and manageable safety profile.
“These eight-year data are highly encouraging,” Sweeney noted. “They confirm the sustained efficacy of XTANDI in both overall survival and disease progression, extending its value across the full trajectory of metastatic hormone-sensitive prostate cancer.”
A Global Standard in Prostate Cancer Care
XTANDI, co-commercialized by Astellas and Pfizer, has transformed the treatment landscape since its initial regulatory approval in 2012. The drug is currently approved in over 90 countries, including major markets such as the United States, European Union, and Japan. To date, more than one million patients worldwide have received treatment with enzalutamide—a testament to its central role in modern prostate cancer management.
As data from ARCHES and ENZAMET continue to accumulate, XTANDI is not only helping patients live longer but also reshaping clinical practice in mHSPC. The compelling long-term survival outcomes presented at ASCO 2025 reinforce its standing as a frontline option for men diagnosed with metastatic hormone-sensitive disease, offering renewed optimism for improved outcomes in a population that previously faced limited treatment success.
