The Vanishing Clinical Value of PD-L1 Status as a Predictive Biomarker in the First-Line Treatment of Urothelial Carcinoma of the Bladder

Simple Summary Bladder cancer is the sixth most common cancer in the world. With 73 years, bladder cancer has the highest age-at-diagnosis of all cancers. While the surgical removal of the bladder remains the standard-of-care treatment for advanced muscle-invasive disease, around half of patients still metastasize. Then, platinum-based chemotherapy is recommended as the first-line treatment. However, only about half of those patients are eligible to receive chemotherapy, and novel immune-checkpoint inhibitors are restricted to biomarker (PD-L1)-positive patients. In our study, we demonstrate that PD-L1-positive patients show slower progression. However, there is no benefit in overall survival, emphasizing the need for novel and more reliable biomarkers in the future.Abstract Background: Our study endeavors to elucidate the clinical implications of PD-L1 positivity in individuals afflicted with advanced urothelial carcinoma of the bladder (UCB). Methods: Patients with advanced UCB were prospectively enrolled following a radical cystectomy (RC) performed within January 2017 to December 2022 at our tertiary referral center. The clinical outcome, defined as the progression-free survival (PFS) and overall survival (OS) on systemic treatment, was analyzed using an chi 2-test, Mann-Whitney U-test, the Kaplan-Meier method, and a log-rank test. Results: A total of 648 patients were included following an RC performed within January 2017 to December 2022. Their PD-L1 status was analyzed with the primary PD-L1-specific antibody (clone SP263, Ventana) and defined both by the CPS and IC-score in 282 patients (43.5%) with a high risk (pT3-pT4 and/or lymph node involvement) or metastatic UCB. While the median PFS was significantly prolonged 5-fold in PD-L1+ patients, we found no difference in OS, regardless of PD-L1 status, or treatment regimen. Conclusions: While PD-L1 positivity indicates prolonged PFS, the presence of PD-L1 does not influence OS rates, suggesting its limited usefulness as a prognostic biomarker in bladder cancer. However, the positive correlation between an PD-L1 status and a sustained response to ICI treatments indicates its potential role as a predictive biomarker. Further research is required to understand how the predictive value of PD-L1 positivity may extend to the use of ICIs in combination with antibody-drug conjugates.