Astellas and Pfizer have released five-year follow-up results from the open-label extension of the Phase III ARCHES trial, which evaluated the effectiveness of Xtandi (enzalutamide) in combination with androgen deprivation therapy (ADT) in men with metastatic hormone-sensitive prostate cancer (mHSPC). The study, which enrolled 1,150 participants across multiple countries, showed that the combination therapy reduced mortality risk by 30% compared to placebo plus ADT. The findings offer a long-term perspective on the overall survival benefits of Xtandi, an androgen receptor pathway inhibitor.
The results indicated that patients treated with the combination therapy experienced a significant reduction in mortality risk, with a 36-month improvement in median overall survival for those with high-volume disease. The study also assessed various subgroups, including those with low-volume disease and those previously treated with docetaxel, and found consistent survival improvements across all groups.
The occurrence of treatment-emergent adverse events during the five-year follow-up was consistent with previous analyses from the ARCHES trial, with no new safety concerns identified. The study’s primary endpoint was radiographic progression-free survival, with overall survival as a key secondary endpoint. The post hoc five-year analysis aimed to provide a comprehensive view of long-term survival benefits.
Astellas’ executive vice-president, Shontelle Dodson, stated that the collective data for Xtandi continues to reinforce its long-term efficacy and patient impact in prostate cancer, including in the metastatic setting. Xtandi has been approved for use in over 90 countries, including the European Union, Japan, and the US. Astellas is responsible for global manufacturing and commercialization outside the US, while both companies jointly market the therapy within the US.
The results of this study are significant, as they demonstrate the long-term benefits of Xtandi in combination with ADT in men with mHSPC. The reduction in mortality risk and improvement in overall survival are promising findings, and the study’s results are expected to inform treatment decisions for patients with this type of cancer. Additionally, the study’s findings are consistent with previous analyses, which further reinforces the efficacy and safety of Xtandi in this patient population. Overall, the results of this study highlight the importance of Xtandi as a treatment option for men with mHSPC.