Ineffectiveness of immune checkpoint inhibitors in prostate cancer: is it just a question of '-mabs'?

Prostate cancer (PCa) is the second most common type of neoplasm, currently treated with a variety of therapeutic agents. Although advances in treatment over the past decade have improved overall survival, patients with advanced PCa eventually progress from hormone-sensitive PCa to metastatic castration-resistant PCa. For this reason, other therapeutic strategies, including immunotherapy, are being investigated. Despite initial enthusiasm, these approaches have not yet produced significant improvements in either progression free survival or overall survival. Several factors may have contributed to the consistently disappointing results of immune checkpoint inhibitors in PCa, despite their more successful results in other tumor types. In this review, we discuss the potential reasons for these disappointing clinical results. © 2026 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.