Background
Patients with mUC have limited options after progression on PLT/ CPI. SG is an antibody-drug conjugate composed of a humanized IgG1 kappa anti–Trop-2 monoclonal antibody coupled to SN-38 via a unique hydrolyzable linker. TROPHY-U-01 cohort 1 interim results (n=35) reported a 29% objective response rate (ORR). FDA has granted fast track designation for SG (TRODELVY™) in mUC.
Methods
TROPHY-U-01 (NCT03547973) is a multicohort, global, open-label, phase 2 study evaluating SG clinical activity (10 mg/kg, days 1 and 8 of 21-day cycles) in patients with unresectable locally advanced or mUC with measurable disease, ECOG PS 0–1, and creatinine clearance ≥30 mL/min. Cohort 1 includes patients progressing after PLT and CPI, with unlimited prior lines of therapy. Primary objective was ORR evaluated by RECIST v1.1 via central review; secondary objectives were progression-free survival (PFS), overall survival (OS), duration of response (DOR), and safety. This cohort had a Simon two-stage design with 90% power to reject the null hypothesis of ORR ≤12%.
Results
113 patients (78% male; median age 66 y; 72% ECOG PS 1; Bellmunt score 0 [12%],1 [54%], 2 [27%],3 [6%]; 62% with visceral metastases) received a median of 3 prior therapies. Central review confirmed an ORR of 27% (31/113; 95% CI 19–37) with 6 complete responses, 25 partial responses and 25% (95% CI 11.5–43.4) ORR in patients with liver metastases. Median DOR was 5.9 mo (95% CI 4.7–8.6) and clinical benefit rate was 37% (42/113). Median PFS and OS were 5.4 mo (95 %CI 3.5- 6.9) and 10.5 mo (95 %CI 8.2–12.3), respectively. Key grade ≥3 treatment-related adverse events were neutropenia (35%), anemia (14%), febrile neutropenia (10%), and diarrhea (10%). There was no treatment-related grade >2 ocular toxicity, neuropathy or interstitial lung disease. There was 1 treatment-related death (neutropenic sepsis).
Conclusions
SG demonstrated meaningful efficacy with manageable toxicity. These results confirm interim findings, suggest that SG may be a treatment option for mUC, and support a randomized phase III trial.