Enzalutamide Maintenance Following Docetaxel in Metastatic Castration-Naive Prostate Cancer: A Pilot Feasibility Study

Abstract

Purpose To assess the feasibility and short-term efficacy of maintenance enzalutamide following first-line docetaxel plus androgen deprivation therapy (ADT) in patients with high-volume, metastatic castration-naive prostate cancer (mCNPC). Materials and Methods The present study included 38 consecutive patients with mCNPC who did not have disease progression with ADT plus docetaxel between October 2022 and October 2023. Patients received a switch maintenance therapy with enzalutamide until progression, unacceptable toxicity, or patient withdrawal. Endpoints included time to prostate-specific antigen (PSA) progression and safety. Results Among the 38 patients, the median age was 68 years, and the most frequently observed metastatic site was bone (n=36), followed by lymph nodes (n=28), lung (n=8), and liver (n=1). The median duration of firstline docetaxel was 2.8 months (range, 2.7–5.0 months). At the time of commencing maintenance enzalutamide, the median PSA was 3.2 ng/mL (range, 0.01–258 ng/mL). Maintenance enzalutamide was generally welltolerated. A total of 11 patients (28%) discontinued enzalutamide, and the main reasons included adverse events (prolonged fatigue of grade 1 or 2, n=6), disease progression (n=3) and financial burdens (n=2). Median time to PSA progression was not reached, and 93% were PSA progression-free at 12 months. Conclusions Maintenance enzalutamide is a feasible treatment option with potential clinical benefit for patients with high-volume mCNPC who were progression-free after first-line ADT+docetaxel.

Keywords

• enzalutamide
• prostatic neoplasms
• castration-naive