Immune-Related Adverse Events and Clinical Outcomes in Advanced Urothelial Cancer Patients Treated With Immune Checkpoint Inhibitors

Background: In advanced urothelial cancers (UC), immune checkpoint inhibitors (ICI) show promise as a durable therapy. Immune-related adverse events (irAEs), a side effect of ICIs, may serve as an indicator of beneficial response. We investigated the relationship between irAEs and clinical outcomes in patients with advanced UC who received ICI.

Materials and methods: In this retrospective study, we investigated 70 patients with advanced UC treated with ICIs at Winship Cancer Institute from 2015 to 2020. Data on patients were collected through chart review. Cox's proportional hazard model and logistic regression were applied to estimate the association with overall survival (OS), progression-free survival (PFS), and clinical benefit (CB). The possible lead-time bias was handled in extended Cox regression models.

Results: The median age of the cohort was 68. Over one-third (35%) of patients experienced an irAE, with skin being the most frequent organ involved (12.9%). Patients that experienced at least one irAE had significantly enhanced OS (HR: 0.38, 95% CI, 0.18-0.79, P = .009), PFS (HR: 0.27, 95% CI, 0.14-0.53, P < .001), and CB (OR: 4.20, 95% CI, 1.35-13.06, P = .013). Patients who experienced dermatologic irAEs also had significantly greater OS, PFS, and CB.

Conclusion: Of patients with advanced UC that had undergone ICI therapy, those who had irAEs, especially dermatologic irAEs, had significantly greater OS, PFS, and CB. These results may suggest that irAE's may serve as an important marker of durable response to ICI therapy in urothelial cancer. The findings of this study need to be validated with larger cohort studies in the future.