Sequential enfortumab vedotin (EV) after platinum-based chemotherapy in metastatic or locally advanced urothelial cancer: Complete response, bladder preservation and survival.

Abstract

529 Background: For metastatic or unresectable invasive urothelial cancer (UC), standard first-line platinum-based chemotherapy achieved progression-free survival (PFS) of 4–7 months. Complete response (CR) rate is <10%. The minority of patients downstaged after chemotherapy followed by cystectomy still suffer from loss of bladder function and a high risk of recurrence. To improve PFS, CR, and bladder preservation, we explored the use of EV after platinum-based chemotherapy in patients with metastatic or locally advanced UC who desired bladder preservation. Methods: Patients with metastatic or locally advanced unresectable UC who desired bladder preservation and received EV after platinum-based chemotherapy were identified. CR was defined as no evidence of disease identified on both radiology (MRI+CT) and cystoscopy; PFS were calculated from the date of initial treatment (first-line chemotherapy) to the date of last follow-up/death or recurrence via Kaplan-Meier analysis. Results: A total of 12 patients were identified: median age was 69.5 years (range, 52–83); 10 (83%) were men; 9 (75%) partial response and 3 (25%) disease progression were observed from platinum-based chemotherapy. EV was given after platinum-based chemotherapy to all 12 patients who subsequently achieved 100% of response: CR was achieved in 7 (58%) patients, and 4 (33%) remained disease free without ongoing treatment, their disease-free survival (DFS) was 9 months (range, 4–18); 2 patients who achieved CR then recurred as carcinoma in situ (CIS), one of whom had a cystectomy with TisN0 confirmed on final pathology. 2 (17%) patients received radiation to bladder and nodal area. Eleven (92%) patients retained their bladders and no patients died. Median follow-up was 19 months (range, 3.4–53.6). The median duration of EV was 7.5 months (range, 2–20). One-year PFS with bladder intact was 83%. Detailed clinical characteristics and outcome listed on Table. Conclusions: For patients with locally advanced or metastatic UC who desired bladder preservation, platinum-based chemotherapy followed by EV with or without pembrolizumab showed encouraging CR and PFS and deserves to be explored further. [Table: see text]