Metastatic hormone-sensitive prostate cancer patients administered ADT plus enzalutamide demonstrated significantly prolonged survival.
Enzalutamide adjunctive to androgen deprivation therapy (ADT) has been approved for treating metastatic hormone-sensitive prostate cancer (mHSPC) based on the clinical benefits in the ARCHES Trial Phase III. Enzalutamide with ADT, during primary analysis, reduced the risk of radiographic disease progression and death in the affected men. This study, published in the Journal of Clinical Oncology, reported final overall survival (OS) data analysis and updated the radiographic progression-free survival (rPFS) along with the safety and other secondary endpoints.
The investigators randomly assigned the 1150 enrolled participants with mHSPC 1:1 to placebo plus ADT and ADT plus 160 mg/day enzalutamide. The key secondary endpoint of the study was OS, and other key points included rPFS. Following unblinding, 180 progression-free study participants assigned to ADT plus placebo were crossed over to ADT plus open-label enzalutamide.
The authors observed that at medium follow-up of 44.6 months, 154 out of 574 patients assigned to ADT plus enzalutamide and 202 out of 576 patients assigned to ADT plus placebo had died, making a total of 356 patient deaths. Compared to placebo plus ADT, patients assigned to ADT plus enzalutamide had a 34% reduction in the risk of death. The number of participants estimated to be alive at 24, 36, and 48 months were 86%, 78%, and 71% (ADT plus enzalutamide) and 82%, 69%, and 57% (placebo plus ADT) , respectively. Median OS was 47.7 months for participants receiving placebo plus ADT.
The clinical benefits were consistent for enzalutamide plus ADT soft tissue disease in 96 participants at the baseline. Survival benefits were confirmed for participants receiving enzalutamide plus ADT, except for patients with visceral and lymph node metastases. There was a delay in the initial, subsequent antineoplastic therapy, castration resistance, and the initial symptomatic skeletal event for patients receiving ADT plus enzalutamide. In contrast to ADT plus placebo, the risk for death or the radiographic progression was reduced by 37% in participants randomized to ADT plus enzalutamide.
One hundred seventeen patients assigned to ADT plus enzalutamide demonstrated PSA progression versus 259 patients assigned to ADT plus placebo. PSA and radiographic progression slowed as crossover was reached in patients randomized to ADT plus placebo. The authors identified no novel safety signals in the study.
The study concluded that treatment comprising enzalutamide plus ADT significantly increases the survival duration as compared to ADT plus placebo in patients diagnosed with mHSPC. It is suggested that the long-term use of enzalutamide is well-tolerated and does not increase toxicity, an important feature for doctors to consider when choosing a systemic treatment for advanced prostate cancer.
Armstrong, A. J., Azad, A. A., Iguchi, T., Szmulewitz, R. Z., Petrylak, D. P., Holzbeierlein, J., Villers, A., Alcaraz, A., Alekseev, B., Shore, N. D., Gomez-Veiga, F., Rosbrook, B., Zohren, F., Yamada, S., Haas, G. P., & Stenzl, A. (2022). Improved Survival With Enzalutamide in Patients With Metastatic Hormone-Sensitive Prostate Cancer. Journal of Clinical Oncology, 40(15), 1616-1622. https://doi.org/10.1200/jco.22.00193