156P - The association between response to enfortumab vedotin therapy and primary tumor location in Japanese urothelial carcinoma patients

Background

Enfortumab vedotin (EV) was approved for patients with unresectable urothelial carcinoma who progressed after anti-cancer therapy on September 2021 in Japan based upon findings in the phase III EV-301 trial (NCT03474107). In the study upper tract urothelial carcinoma (UTUC) patients accounted for approximately 30% and the upper limit of hazard ratio of EV for progression-free survival was greater than 1. Therefore, we reviewed the association between response to EV therapy and primary tumor location in Japanese urothelial carcinoma patients using our real-world data.

Methods

We identified 27 patients treated with EV therapy for advanced unresectable carcinoma at our two institutions from the approval to June 2022. The median follow-up periods were 2.4 months (range: 1-7 months). We evaluated the difference on the response rate and incidence of adverse effects between UTUC patients (N=15, 55.6%) and bladder cancer (BC) patients (N=12, 44.4%).

Results

Median age of UTUC and BC patients were 74.5 and 76.2 years, respectively. No difference on the percentage of cisplatin-based 1^st line chemotherapy performed was observed between UTUC patients (69%) and BC patients (88%, p=0.340). Twenty-one patients could be assessed on the effect of EV therapy. Of them best overall effects in UTUC patients were complete response (CR) in 0, partial response (PR) in 5, stable disease (SD) in 6, and progressive disease (PD) in 2. Best overall effects in BC patients were CR in 1, PR in 2, SD in 4, and PD in 1. Subsequently, the overall response rate of UTUC and BC patients were 38.5% and 37.5%, respectively (p>0.9). The disease control of UTUC and BC patients were 87.5% and 84.6%, respectively (p>0.9). Grade 3 adverse effects was observed in 4 UTUC patients (30.8%) and 3 BC patients (37.5%) with no significant difference (p>0.9).

Conclusions

In a real-world setting, the response to and an adverse effect on EV therapy might be the same between UTUC and BC patients.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

N. Hayakawa: Non-Financial Interests, Personal, Speaker’s Bureau: Astellas Pharma Inc. Japan. E. Kikuchi: Non-Financial Interests, Personal, Speaker’s Bureau: Astellas Pharma Inc. Japan., Merck. All other authors have declared no conflicts of interest.