Astellas and Pfizer Announce Long-Term Follow-Up Results of XTANDI in Metastatic Prostate Cancer

Astellas Pharma Inc. and Pfizer Inc. have announced longer-term follow-up results from an open-label extension of the Phase 3 ARCHES study, showing a significant improvement in overall survival benefits and a 30% reduction in the risk of death in men with metastatic hormone-sensitive prostate cancer (mHSPC) treated with XTANDI. These findings have significant implications for the treatment of advanced prostate cancer.

Key Takeaways:

• The five-year follow-up of the ARCHES study demonstrated a 30% reduction in the risk of death in men with mHSPC treated with XTANDI, compared to placebo.
• The study found a 13% absolute and 30% relative improvement in overall survival (OS) benefits for patients treated with XTANDI, compared to standard hormonal therapy alone.
• Patients with high and low disease burden showed consistently improved survival, with a 36-month improvement in median OS observed in patients with high-volume disease.
• Subgroups of patients, including those who had previously received docetaxel therapy, showed improved survival with XTANDI.
• The incidence of treatment-emergent adverse events in the five-year follow-up was consistent with prior ARCHES analyses, and no new safety signals were identified.

Statistics:

• 30% reduction in the risk of death in men with mHSPC treated with XTANDI
• 13% absolute improvement in overall survival (OS) benefits
• 30% relative improvement in OS benefits
• 36-month improvement in median OS in patients with high-volume disease
• 2/3 of men with mHSPC are now surviving five years, representing a significant improvement over standard hormonal therapy alone

Sources:

• Astellas Pharma Inc.
• Pfizer Inc.
• NCT02877896 (ARCHES study)
• NCT02446405 (ENZAMET study)
• American Society of Clinical Oncology (ASCO) Annual Meeting