Adoption of immune checkpoint inhibitors (ICI) for unresectable locally advanced or metastatic urothelial carcinoma (u/mUC): A retrospective assessment of community oncology practices.

Abstract

293 Background: ICI approval provided new treatment options for patients (pts) with u/mUC. We aimed to assess the adoption of ICI and describe 1L treatment patterns in the US community oncology setting. We hypothesized that most pts would receive ICI either as first- (1L) or second- line (2L) treatment given their FDA approval indications within the study period. Methods: This was a retrospective study of all study-eligible adult pts with u/mUC who initiated 1L treatment between 5/1/16 – 11/30/18 within The US Oncology Network. Data were sourced from structured and unstructured electronic health record data through 5/31/19 and assessed descriptively. Results: Among 750 eligible pts, 327 received 1L ICI (median age 74, 72.5% men, 77.1% white, 27.2% never smokers, 63.6% Eastern Cooperative Oncology Group performance status (ECOG PS] score of 0/1) and 423 1L non-ICI agents (median age 72, 74.0% men, 84.2% white, 26.0% never smokers, 60.5% ECOG PS score of 0/1). The most common treatment sequences were 1L ICI or 1L non-ICI without 2L treatment (n = 301 [40.1%] and n = 197 [26.3%], respectively), followed by 1L non-ICI and 2L ICI (n = 176, 23.5%). Platinum-based chemotherapy was the most common non-ICI therapy. Among a subset of patients randomly selected for chart review who received 1L ICI (n = 70), the most common reasons for 1L discontinuation were death (22.9%), transition to hospice (21.4%) and disease progression (11.4%). In contrast, the most common reason for 1L discontinuation among patients who received 1L non-ICI therapy selected for chart review (n = 133) were toxicity (27.8%), disease progression (22.6%) and completion of planned treatment (19.5%). Conclusions: As a retrospective observational study, limitations include lack of randomization, missing data, selection bias and unmeasured confounders. The high proportion of pts who received ICI during this period suggests enthusiasm for new therapies with less toxicity than chemotherapy. Nonetheless, the high attrition across treatment lines indicates an unmet need for tolerable and effective 1L u/mUC therapies, including switch maintenance ICI, which recently emerged as the new standard of care with level I evidence. Further investigation is needed to understand factors considered by pts and providers when determining treatment, as well as prognostic and predictive biomarkers.