Treatment Rechallenge With Immune Checkpoint Inhibitors in Advanced Urothelial Carcinoma.

OBJECTIVES: To examine patient and disease characteristics, toxicity, and clinical outcomes for patients with advanced urothelial carcinoma (aUC) who are rechallenged with immune checkpoint inhibitor (ICI)-based therapy. PATIENTS AND METHODS: In this retrospective cohort, we included patients treated with ICI for aUC after having prior ICI treatment. Endpoints included the evaluation of radiographic response and disease control rates with first and second ICI courses, outcomes based on whether there was a change in ICI class (anti-PD-1 vs. anti-PD-L1), and assessment of the reasons for ICI discontinuation. RESULTS: We identified 25 patients with aUC from 9 institutions who received 2 separate ICI courses. ORR with first ICI and second ICI were 39% and 13%, respectively. Most patients discontinued first ICI due to progression (n = 19) or treatment-related toxicity (n = 4). Thirteen patients received non-ICI treatment between the first and second ICI, and 12 patients changed ICI class (anti-PD-1 vs. anti-PD-L1) at rechallenge. Among 10 patients who changed ICI class, 8 (80%) had progressive disease as best response with second ICI, while among 12 patients re-treated with the same ICI class, only 3 (25%) had progressive disease as best response at the time of rechallenge. With second ICI, most patients discontinued treatment due to progression (n = 18) or patient preference (n = 2). CONCLUSIONS: A proportion of patients with aUC rechallenged with ICI-based regimens may achieve disease control, supporting clinical trials in that setting, especially with ICI-based combinations. Future studies are needed to validate our results and should also focus on identifying biomarkers predictive of benefit with ICI rechallenge.

Association of the Time to Immune Checkpoint Inhibitor (ICI) Initiation and Outcomes With Second Line ICI in Patients With Advanced Urothelial Carcinoma.

BACKGROUND: Early progression on first-line (1L) platinum-based therapy or between therapy lines may be a surrogate of more aggressive disease and poor outcomes in advanced urothelial carcinoma (aUC), but its prognostic role regarding immune checkpoint inhibitor (ICI) response and survival is unclear. We hypothesized that shorter time until start of second-line (2L) ICI would be associated with worse outcomes in aUC. PATIENTS AND METHODS: We performed a retrospective multi-institution cohort study in patients with aUC treated with 1L platinum-based chemotherapy, who received 2L ICI. Patients receiving switch maintenance ICI were excluded. We defined time to 2L ICI therapy as the time between the start of 1L platinum-based chemotherapy to the start of 2L ICI and categorized patients a priori into 1 of 3 groups: less than 3 months versus 3-6 months versus more than 6 months. We calculated overall response rate (ORR) with 2L ICI, progression-free survival (PFS) and overall survival (OS) from the start of 2L ICI. ORR was compared among the 3 groups using multivariable logistic regression, and PFS, OS using cox regression. Multivariable models were adjusted for known prognostic factors. RESULTS: We included 215, 215, and 219 patients in the ORR, PFS, and OS analyses, respectively, after exclusions. ORR difference did not reach statistical significance between patients with less than 3 months versus 3-6 months versus more than 6 months to 2L ICI. However, PFS (HR 1.64; 95% CI 1.02-2.63) and OS (HR 1.77; 95% CI 1.10-2.84) was shorter among those with time to 2L ICI less than 3 months compared to those who initiated 2L ICI more than 6 months. CONCLUSION: Among patients with aUC treated with 2L ICI, time to 2L ICI less than 3 months was associated with lower, but not significantly different ORR, but shorter PFS and OS compared to 2L ICI more than 6 months. This highlights potential cross resistance mechanisms between ICI and platinum-based chemotherapy.

Association Between Sites of Metastasis and Outcomes With Immune Checkpoint Inhibitors in Advanced Urothelial Carcinoma.

BACKGROUND: Sites of metastasis have prognostic significance in advanced urothelial carcinoma (aUC), but more information is needed regarding outcomes based on metastatic sites in patients treated with immune checkpoint inhibitors (ICI). We hypothesized that presence of liver/bone metastases would be associated with worse outcomes with ICI. METHODS: We identified a retrospective cohort of patients with aUC across 26 institutions, collecting demographics, clinicopathological, treatment, and outcomes information. Outcomes were compared with logistic (observed response rate; ORR) and Cox (progression-free survival; PFS, overall survival; OS) regression between patients with/without metastasis beyond lymph nodes (LN) and those with/without bone/liver/lung metastasis. Analysis was stratified by 1st or 2nd+ line. RESULTS: We identified 917 ICI-treated patients: in the 1st line, bone/liver metastases were associated with shorter PFS (Hazard ratio; HR: 1.65 and 2.54), OS (HR: 1.60 and 2.35, respectively) and lower ORR (OR: 0.48 and 0.31). In the 2nd+ line, bone/liver metastases were associated with shorter PFS (HR: 1.71 and 1.62), OS (HR: 1.76 and 1.56) and, for bone-only metastases, lower ORR (OR: 0.29). In the 1st line, LN-confined metastasis was associated with longer PFS (HR: 0.53), OS (HR:0.49) and higher ORR (OR: 2.97). In the 2nd+ line, LN-confined metastasis was associated with longer PFS (HR: 0.47), OS (HR: 0.54), and higher ORR (OR: 2.79); all associations were significant. CONCLUSION: Bone and/or liver metastases were associated with worse, while LN-confined metastases were associated with better outcomes in patients with aUC receiving ICI. These findings in a large population treated outside clinical trials corroborate data from trial subset analyses.