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

• Published in: European urology oncology Vol. 4; no. 1; pp. 117 - 120
• Main Authors: Kates, Max, Nirschl, Thomas R., Baras, Alex S., Sopko, Nikolai A., Hahn, Noah M., Su, Xiaoping, Zhang, Jiexin, Kochel, Christina M., Choi, Woonyoung, McConkey, David J., Drake, Charles G., Bivalacqua, Trinity J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.02.2021
• Subjects: B7-H1 Antigen - antagonists & inhibitors; Bladder cancer; Carcinoma, Transitional Cell; CD8-Positive T-Lymphocytes; Flow Cytometry; High-Throughput Nucleotide Sequencing; Humans; Immune checkpoint blockade; Immune Checkpoint Inhibitors - therapeutic use; Prospective Studies; T-Lymphocytes, Regulatory; Urinary Bladder Neoplasms - drug therapy; Immune checkpoint blockade; Bladder cancer
• ISSN: 2588-9311; 2588-9311
• DOI: 10.1016/j.euo.2019.01.017

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. 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. As urothelial carcinoma becomes resistant to PD-L1 blockade, additional immune checkpoints may be upregulated, leading to anti-PD-L1 resistance. These data support the concept of combined checkpoint blockade for urothelial carcinoma.