Combined Next-generation Sequencing and Flow Cytometry Analysis for an Anti-PD-L1 Partial Responder over Time: An Exploration of Mechanisms of PD-L1 Activity and Resistance in Bladder Cancer.

Anti-PD-L1/PD-1 immunotherapy has improved survival for certain patients with metastatic urothelial carcinoma. However, the mechanisms of resistance to these agents have not been fully elucidated. We report the first combined analysis using RNA sequencing, whole-exome sequencing (WES), and flow cytometry of multiple tumor specimens over a 5-yr period for a patient undergoing anti-PD-L1 therapy. Initial sensitivity to anti-PD-L1 immunotherapy was associated with conversion to a basal molecular subtype and a rising tumor mutational burden. We found that as the tumor became more resistant to anti-PD-L1, the proportion of regulatory T cells and CD8+ T cells expressing alternative immune checkpoints including CTLA-4, TIM-3, and LAG-3 increased. This suggests that alternative immune checkpoint upregulation may be one form of anti-PD-L1 resistance in urothelial carcinoma. These data support the concept of combined immune checkpoint blockade for urothelial carcinoma, a concept that is being evaluated in prospective clinical trials. PATIENT SUMMARY: In this study we characterized how a patient with metastatic urothelial cancer became resistant to anti-PD-L1 immunotherapy. By tracking changes in protein and gene expression over time, we found that as urothelial carcinoma becomes resistant to PD-L1 blockade, additional immune checkpoints may be upregulated. These data support the concept of combined checkpoint blockade for urothelial carcinoma.

European urology oncology. 2019 Feb 26 [Epub ahead of print]

Max Kates, Thomas R Nirschl, Alex S Baras, Nikolai A Sopko, Noah M Hahn, Xiaoping Su, Jiexin Zhang, Christina M Kochel, Woonyoung Choi, David J McConkey, Charles G Drake, Trinity J Bivalacqua

Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD, USA; Sydney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA; Greenberg Bladder Cancer Institute, Johns Hopkins Medical Institutions, Baltimore, MD, USA. Electronic address: ., Sydney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA., Sydney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA; Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD, USA., Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD, USA., Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD, USA; Sydney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA; Greenberg Bladder Cancer Institute, Johns Hopkins Medical Institutions, Baltimore, MD, USA., Department of Bioinformatics and Computational Biology, MD Anderson Cancer Center, Houston, TX, USA., Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD, USA; Greenberg Bladder Cancer Institute, Johns Hopkins Medical Institutions, Baltimore, MD, USA., Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY, USA.