Liquid Biopsy as a Biomarker in Patients Treated With PSMA Radioligand Therapy

Prostate cancer is the second most common cause of cancer death in men worldwide. After exhausting guideline-compliant therapies or in accordance with the approval of 177Lu-PSMA-617 (Pluvicto®), patients with metastatic castration-resistant prostate cancer (mCRPC) can be offered radioligand therapy (RLT) that targets the prostate-specific membrane antigen (PSMA). Despite an initially high response rate to PSMA-RLT, the disease often progresses rapidly again. The underlying mechanisms are still poorly understood.

Liquid biopsy (LBx) involves the collection and analysis of body fluids, particularly blood. Its major advantage compared to a tissue sample is its non-invasive nature, allowing for multiple samplings, as well as the examination of more than just a single punctured lesion. Among other things, circulating tumor DNA (ctDNA) can be detected in the blood.

The aim of this study is to apply LBx before, during, and after PSMA-RLT in patients with mCRPC to determine prognostic factors before therapy and to assess the value of LBx in evaluating treatment response. Furthermore, LBx will be used to gather information on the course of potential tumor heterogeneities and to determine resistance mechanisms against PSMA-RLT.

To this end, patients receiving PSMA-RLT will be enrolled in the study at three sites (University Hospital Wuerzburg, University Hospital Augsburg, Klinikum rechts der Isar Munich). The evaluation of clinical and imaging parameters will be carried out centrally at the University Hospital Wuerzburg, while the analysis of LBx will be performed at the University Hospital Augsburg.