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

Abstract

377 Background: The effect of prior immune checkpoint inhibition therapy (CI) on the efficacy of subsequent chemotherapy is largely unknown in MUB. 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 20 sequential patients collected from one institution who received chemotherapy after CI. Patients were separated into 2 groups. Group A had not previously received chemotherapy (n=10), group B had previously received at least 1 chemotherapy regimen (n=10). 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). The commonest chemotherapy regimen in group A and B were cisplatin-gemcitabine (80%) and carboplatin paclitaxel (70%) respectively. Results are summarised in the table. The median change in target lesions in the front line immunotherapy cohort was -49% (-81 to +8%). Only two patients (20%) in group B responded to chemotherapy and both presented a long interval between first and 2ndline chemotherapy (9-12 months); compared to 56% responding in group A. 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. [Table: see text]