SALVAGE RADIOTHERAPY IN COMBINATION WITH PEMBROLIZUMAB IN PATIENTS WITH PSA PERSISTENCE OR BIOCHEMICAL RECURRENCE AFTER RADICAL PROSTATECTOMY DUE TO PROSTATE CANCER

• Published in: Urologic oncology Vol. 42; p. S17
• Main Authors: Grabbert, Markus, Zamboglou, Constantinos, Spohn, Simon, Jilg, Cordula, Sigle, August, Himmelsbach, Ruth, Liakos, Nikolaos, Astheimer, Sophie, Schäfer, Henning, Sprave, Tanja, Grosu, Anca-Ligia, Gratzke, Christian
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-03-2024
• ISSN: 1078-1439; 1873-2496
• DOI: 10.1016/j.urolonc.2024.01.076

The combination of immunotherapy (IO) with radiation therapy might provide a clinical benefit to our patients due to a synergistic effect. Radiation therapy of the location of recurrence might lead to an increase in the immunogenic potential and;a systemic immunological reaction is described that leads to an increased activity of the immune system against cancerous tissue (abscopal effect). The goal of our study is to evaluate the efficacy and safety of immunotherapy in combination with standard salvage radiation therapy (SRT) in patients with biochemical recurrence (BCR) of prostate-specific antigen (PSA) persistence after radical prostatectomy (RP). Primary endpoint is complete biochemical response (PSA level below detection level) 60 weeks after start of trial treatment, which further defines prognosis of patients and the further course of disease. Further explorative endpoints like radiographic progression-free survival, PSA-nadir level and time to PSA-nadir, time to initiation of subsequent therapy (secondary ADT or NHA).
The trial is as a phase II, open-label, single arm monocenter trial which evaluates the combination of pembrolizumab;in combination with SRT. Pembrolizumab will be administered in a three-weekly scheme up to one year of treatment. A concomitant ADT is administered in high-risk patients only (PSA >0.7ng/ml or cN+ in imaging studies). All patients will be staged with PSMA PET-CT, if applicable. Additionally, blood and urine samples will be collected for correlative biomarker studies.Imaging within 30 days prior to study inclusion is mandatory (([68Ga] or [18F] PSMA PET-CT as standard imaging modality, alternatively CT abdomen and full-body bone scan) is one of the important inclusion crtieria.Prior systemic anti-cancer therapy including investigational agents within 4 weeks prior to registration (like neo-adjuvant androgen deprivation therapy (ADT), secondary hormone ablation or taxan-based chemotherapy) and distant metastases or suspicious lymph nodes outside the lower pelvis;are important exclusion criteria.
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