Dr Vlachou on Primary Tumor Responses With Enfortumab Vedotin in Upper Tract Urothelial Cancer

“These numbers show us that we need to further assess the efficacy of enfortumab vedotin and enfortumab vedotin/pembrolizumab in the perioperative setting [through] larger, prospective studies.”

Evangelia Vlachou, MD, postdoctoral research fellow, Departments of Medical Oncology and Urology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins, discusses findings from a retrospective study investigating primary tumor responses with enfortumab vedotin-ejfv (Padcev) with or without pembrolizumab (Keytruda) in patients with upper tract urothelial cancer.

This study evaluated response rates and disease control rates (DCRs) in patients with high-grade, locally advanced or metastatic upper tract urothelial cancer and intact primary tumors who were treated with enfortumab vedotin alone or in combination with pembrolizumab. Between December 2017 and June 2024, investigators identified 22 patients with intact primary tumors. Patients had a median age of 72 years, 59.1% of patients were male, 77.3% of patients were White, and 86.4% of patients had pure urothelial cancer histology. In total, 59.1% of patients received enfortumab vedotin monotherapy, and 40.9% of patients received the antibody-drug conjugate in combination with pembrolizumab. Patients received a median of 4 cycles (range, 0.5-14) of enfortumab vedotin. The median duration of treatment was 3.3 months (range, 0.5-10).

Response rates were evaluated by 2 radiologists using RECIST 1.1 criteria among patients with or without target or measurable lesions at baseline scans. The overall response rate was 35.0%, with best responses including partial response (PR; 35.0%), stable disease (SD; 35.0%), and progressive disease (PD; 30.0%). The DCR was 70.0%. Two patients had only non-target lesions at baseline; neither of these patients achieved a complete response (CR) or PD with therapy.

The primary lesion response rate was 25.0%, with best responses including PR (25.0%), SD (45.5%), and PD (12.5%). The DCR was 87.5%. Six patients had only non-target primary tumor lesions at baseline; none of these patients experienced a CR or PD with therapy.

These findings demonstrate the importance of continuing to evaluate the efficacy of enfortumab vedotin with or without pembrolizumab in the perioperative setting through large, prospective clinical trials, Vlachou concludes.