Prognostic Role of PD-L1 Expression in Renal Cell Carcinoma. A Systematic Review and Meta-Analysis

Intratumoral expression of programmed death ligand 1 (PD-L1) in patients with clear cell renal cell carcinoma (ccRCC)

The immunological checkpoints of programmed death 1 and its ligand (PD-L1) are currently in focus as novel therapeutic targets in renal cell carcinoma (RCC). The aim of this study was to evaluate the prognostic association of PD-L1 expression in clear cell (cc) RCC with clinical parameters, tumor aggressiveness and overall survival (OS). Patients who underwent renal surgery due to RCC between 1994 and 2003 were retrospectively evaluated. Tumor specimens were analyzed for PD-L1 expression by immunohistochemistry. One hundred and seventy-seven ccRCC patients were eligible for analysis, in which 140 (79.1 %) were negative and 37 (20.9 %) were positive for PD-L1 expression. PD-L1 positivity was associated with female gender (p = 0.001), lymph node metastasis (p = 0.004), distant metastasis (p = 0.002), higher AJCC stage (p = 0.004), as well as advanced disease (pT3/4 and/or N+ and/or M1) (p < 0.001). Kaplan-Meier analysis revealed a significantly diminished 5- and 10-year overall survival of 46.7 and 28.3 % for PD-L1(+) compared to PD-L1(-) tumors with 66 and 53.4 % (p = 0.005), respectively. Univariate analysis showed a significant negative association of OS with PD-L1 positivity [p = 0.005; HR: 2 (95 % CI 1.2-3.3)], even though PD-L1 positivity only tends to predict independently the OS using multivariate analyses [p = 0.066; HR: 1.6 (95 % CI 0.98-2.7)]. PD-L1 expression in ccRCC is associated with parameters of aggressiveness, as well as with poor OS, even though PD-L1 status was not identified as a significant independent prognostic parameter. However, further studies in larger cohorts are warranted.

Checkpoint Blockade - a New Treatment Paradigm in Renal Cell Carcinoma

Nivolumab is the first checkpoint inhibitor for the treatment of renal cell carcinoma (RCC), which is in line for approval in Europe. Despite its novelty in the treatment algorithm of RCC, it offers a whole new strategy of therapy management with safe applicability. The aim of this work was to review current data on checkpoint inhibitors in RCC and discuss future perspectives for this novel approach in RCC. A selective literature search was performed in the Pubmed database: Nivolumab is a first-in-class agent for the treatment of RCC, and its European label is anticipated for 2016. Contrary to many other agents, nivolumab was able to show a benefit in overall survival and health-related quality of life when compared to everolimus. Current trials focus on optimizing and expanding its use to metastatic RCC. In conclusion, nivolumab has already acquired a role in the treatment algorithm of RCC. However, which patient population derives the most benefit as well its optimal use in the treatment algorithm remain to be determined. A number of ongoing trials will provide novel insights and might help to untangle this novel network of therapy management for immunotherapies.

Immune Checkpoint Inhibitors and Prostate Cancer: A New Frontier?

Despite recent advances in the treatment of metastatic castration-resistant prostate cancer (mCRPC), agents that provide durable disease control and long-term survival are still needed. It is a fact that a tumor-induced immunosuppressive status (mediated by aberrant activation of inhibitory immune checkpoint pathways as a mechanism to evade host immune surveillance) plays a crucial role in the pathogenesis of cancer, including prostate cancer (PC), making CRPC patients suitable candidates for immunotherapy. Therefore, growing interest of anticancer research aims at blocking immune checkpoints (mainly targeting CTLA-4 and PD1/PD-L1 pathways) to restore and enhance cellular-mediated antitumor immunity and achieve durable tumor regression. In this review, we describe the current knowledge regarding the role of immune checkpoints in mediating PC progression, focusing on CTLA-4 and PD1 pathways. We also provide current clinical data available, an update on ongoing trials of immune checkpoint inhibitors in PC. Finally, we discuss the necessity to identify prognostic and predictive biomarkers of immune activity, and we analyze new immune checkpoints with a role as promising targets for PC therapy.