Apalutamide in prostate cancer: clinical evidence, disease modification hypothesis, and emerging treatment de‑intensification strategies

INTRODUCTION: Apalutamide is a potent androgen receptor pathway inhibitor with established efficacy in non-metastatic castration-resistant and metastatic hormone-sensitive prostate cancer. Emerging evidence has also raised questions regarding the biological impact of early treatment, depth of response, and the potential for response-adapted treatment strategies. AREAS COVERED: This narrative review summarizes randomized clinical trials and real-world evidence evaluating apalutamide across the prostate cancer continuum, with particular emphasis on efficacy, safety, PSA kinetics, comparative effectiveness, and treatment de-intensification. PubMed/MEDLINE and the Cochrane Library were searched from database inception through July 2026, supplemented by reference-list screening and relevant conference proceedings. EXPERT OPINION: Apalutamide provides robust evidence of clinical benefit in established indications, while deep PSA responses represent an important prognostic marker that requires prospective validation before being used to guide treatment intensity. The concept of disease modification remains biologically plausible but unproven, and treatment de-intensification should currently be considered investigational. Future studies should integrate longitudinal response assessment, molecular biomarkers, imaging, patient-reported outcomes, and long-term clinical endpoints to identify patients who may safely benefit from treatment adaptation.