Epidemiology and treatment patterns for locally advanced or metastatic urothelial carcinoma: a systematic literature review and gap analysis

BACKGROUND: Several immuno-oncology (IO) agents targeting programmed death-1 or programmed death-ligand 1 (PD-1/L1) are approved second-line therapy options for patients with locally advanced or metastatic urothelial carcinoma (la/mUC) previously treated with platinum-based chemotherapy or first-line options in patients ineligible for cisplatin whose tumors express PD-L1 or for any platinum-based chemotherapy regardless of PD-L1 expression levels. However, literature on the epidemiology of la/mUC is limited, and real-world treatment patterns are not well established, especially with respect to therapies used following IO. OBJECTIVES: To (a) report the epidemiology of urothelial carcinoma (UC) and la/mUC; (b) identify and summarize the published literature on la/mUC treatment patterns, including IO and post-IO treatment; and (c) identify evidence gaps. METHODS: A systematic literature review was conducted using Cochrane dual-reviewer methodology and the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. Literature databases and selected congress abstracts (2017-2018) were searched for retrospective studies published January 2013-August 2018 in English reporting epidemiological and treatment data (all lines of therapy) for adult patients with la/mUC. RESULTS: Among 6,584 database references and 1,832 congress abstracts screened, 45 publications (29 manuscripts, 1 poster, 15 abstracts; reporting 37 unique studies) were retained. All studies related to treatment patterns, and the majority were from the United States (n = 17), Japan (n = 8), and the United Kingdom (n = 5). Epidemiological data were not identified among the searches thus online registries were leveraged. Among the identified publications, 21 (20 unique) reported on cisplatin versus non-cisplatin regimens, 14 (8 unique) on IO, and 9 (7 unique) on vinflunine. Cisplatin use varied both within and among countries (ranging from 18.4% in 1 U.S. study to 87.9% in 1 Japanese study). The use of IO was higher in later lines of therapy, ranging from 1.4% to 7.9% as first-line therapy to 57.8% as second-line and 64.4% as third-line therapy. Among studies reporting IO discontinuation rates, 41.4%-71% of patients were reported to discontinue IO across the studies, and the median time to discontinuation ranged from 2.7 to 5.8 months. Only 25%-35.5% of patients received subsequent therapy following IO discontinuation; post-IO treatments varied widely. CONCLUSIONS: Additional published data on the country-specific epidemiology of UC and la/mUC are needed, including rates of progression from early-stage disease to la/mUC. There was large variation in treatment rates, particularly cisplatin use, within and across countries. The few published real-world IO studies reported high levels of discontinuation with only a small percentage of patients receiving subsequent therapy. As IO therapies continue to be granted regulatory approval in countries outside the United States and novel therapies gain approval in the post-IO setting, the treatment paradigm for patients with la/mUC is shifting, and future studies with more recent data will be required.