Responses to chemotherapy in patients with metastatic urothelial cancer (MUC) after frontline immunotherapy.

Abstract

e16004 Background: The effect of prior immune checkpoint inhibition therapy (CI) on the efficacy of subsequent chemotherapy is largely unknown in MUC. The identification of the optimal sequence of chemotherapy and IO is yet to be determined, but may influence outcomes. Methods: A retrospective audit and comparison of patients who progressed after first and second line CI and received subsequent standard chemotherapy was performed. Date was collected across a broad spectrum of CI. We report on patient’s characteristics and response rates of 28 sequential patients collected from two institutions who received chemotherapy after CI. Patients were separated into 2 cohorts. Cohort A had not previously received chemotherapy (n = 14), cohort B had previously received at least 1 chemotherapy regimen (n = 14). Central radiology review was performed. We assessed objective response rate by RECIST v 1.1. Kaplan Meier method was used. Results: Median age for the whole cohort was 64 yrs (45-80). ECOG was 0/1 in 89,3% and 2 in 10,7% at the time of starting chemotherapy. The commonest chemotherapy regimen in cohort A and B were carboplatin-gemcitabine (71%) and carboplatin paclitaxel (50%) respectively. 75% of the patients were intermediate risk group. In Cohort A 63% responded to chemotherapy whereas in cohort B only 3 patients showed response. The median change in target lesions in the front line immunotherapy cohort was -60% (-81 to +1%). Both patients who responded to 2nd line chemotherapy after CI had a long interval between first and 2nd line chemotherapy (9-24 months). Conclusions: Chemotherapy maintains its efficacy after front line CI with deep responses. Although numbers are modest, results strongly suggest patients should be offered chemotherapy in this setting.