Immunotherapeutic Treatment for Metastatic Prostate Cancer: A Review of Recent Clinical Trials

Metastatic prostate cancer (PC) immunotherapy targets tumor-specific antigens, also known as tumor-associated antigens (TAAs), commonly present in cancer cells. Advancements in PC immunotherapy research studies have shown distinctive and innovative prospective immunotherapy interventions for metastatic PC. Sipuleucel-T, the first immunotherapeutic treatment to treat cases of metastatic castration-resistant PC (mCRPC), is one of these notable, unique, and innovative immunotherapies. This review examines the types of immunotherapies for metastatic PC, along with immunotherapy and combination treatments with immunotherapy, with a particular emphasis on immunotherapy in clinical trials. The goal of immunotherapeutic treatments is to restore the host immune system’s ability to combat PC cells, primarily through natural mechanisms (e.g., the action of cytotoxic T cells on cancer cells) and a variety of mechanisms of action that elicit the desired effect through targeting TAAs, ligand binding, and immune checkpoint inhibitors (ICIs). Researchers have also linked multiple gene mutations and expressions to metastatic PC susceptibility, such as CDK12 mutations. The ability of immunomodulators to enhance the immunoreactivity of PC patients has suggested their use in combination therapeutic approaches with immunotherapy for PC treatment. Recent immunotherapy treatments for metastatic PC have focused on exploring different immune system checkpoint inhibitors, genetic alterations, and PC biomarkers to improve the clinical progression of metastatic PC patients, their overall survival rate, and the partial or complete remission of cancer cells. Furthermore, ongoing clinical research studies on immunotherapy treatment for metastatic PC are currently investigating not only monotherapy immunotherapy treatments but also various combination therapies that can enhance the immunotherapy treatment’s effectiveness.