Targeting STEAP1 as an anticancer strategy

Precision Targeting in Metastatic Prostate Cancer: Molecular Insights to Therapeutic Frontiers

Metastatic prostate cancer (mPCa) remains a significant cause of cancer-related mortality in men. Advances in molecular profiling have demonstrated that the androgen receptor (AR) axis, DNA damage repair pathways, and the PI3K/AKT/mTOR pathway are critical drivers of disease progression and therapeutic resistance. Despite the established benefits of hormone therapy, chemotherapy, and bone-targeting agents, mPCa commonly becomes treatment-resistant. Recent breakthroughs have highlighted the importance of identifying actionable genetic alterations, such as BRCA2 or ATM defects, that render tumors sensitive to poly-ADP ribose polymerase (PARP) inhibitors. Parallel efforts have refined imaging-particularly prostate-specific membrane antigen (PSMA) positron emission tomography-computed tomography-to detect and localize metastatic lesions with high sensitivity, thereby guiding patient selection for PSMA-targeted radioligand therapies. Multi-omics innovations, including liquid biopsy technologies, enable the real-time tracking of emergent AR splice variants or reversion mutations, supporting adaptive therapy paradigms. Nonetheless, the complexity of mPCa necessitates combination strategies, such as pairing AR inhibition with PI3K/AKT blockade or PARP inhibitors, to inhibit tumor plasticity. Immuno-oncological approaches remain challenging for unselected patients; however, subsets with mismatch repair deficiency or neuroendocrine phenotypes may benefit from immune checkpoint blockade or targeted epigenetic interventions. We present these pivotal advances, and discuss how biomarker-guided integrative treatments can improve mPCa management.

[Bispecific antibodies in prostate cancer therapy]

Prostate cancer (PC) is the second most common cancer in men. As soon as androgen deprivation therapy fails, treatment options are limited. Despite intense efforts, hardly any of the T cell-based immunotherapeutic strategies that have revolutionized oncological treatment in other cancer entities are yet established for the treatment of PC. This includes immune checkpoint inhibition, which generally reinforces T cell-immunity but failed to achieve broad activity in PC, as well as chimeric antigen receptor T (CART) cells and bispecific antibodies (bsAbs), which specifically mobilize T cells against tumor cells. Compared to CART cells, bsAbs have the advantage of being readily available "off-the-shelf" reagents. Currently several bispecific constructs are in development for PC. While development of some was discontinued due to substantial side effects or development of anti-drug antibodies, others have yielded promising results. These include in particular bsAbs directed against six-transmembrane epithelial antigen of the prostate 1 (STEAP1) and prostate-specific membrane antigen (PSMA), which are currently being evaluated in both patients with metastasized disease and biochemical relapse. The concepts underlying the different constructs, the current status of clinical development, and future perspectives are discussed.