Abstract 288P
Background
Enfortumab vedotin (EV) monotherapy is a last-line salvage therapy for unresectable and/or metastatic urothelial carcinoma (u/mUC) in Japan. However, the impact of the response of EV to metastatic sites on survival outcomes is not fully understood.
Methods
From the time of approval to May 2024, we identified 117 u/mUC patients treated with EV at 5 institutions. The median follow-up period was 9.6 months (range: 1.0-30.0 months). We evaluated the association between metastatic sites and the treatment response to EV, as well as overall survival (OS).
Results
Overall, the response rate (complete response, CR + partial response, PR) was 49.5%. The median OS and progression-free survival were 13.9 and 6.2 months, respectively. In 56 patients with single-organ metastases, 1, 15, 8, 2, and 30 patients had liver, lung, bone, peritoneal, and lymph node (LN) metastases, respectively. The organ-specific response rate of liver, lung, bone, peritoneal, and LN metastases to EV was 35.7%, 62.2%, 18.8%, 30.8%, and 47.6%, respectively. Among them, the median OS of patients with a response to EV was not reached, which was significantly longer than their counterparts (9.2 months, p<0.001). Furthermore, in 30 patients with single-organ metastasis of LN, the median OS of patients with a response to EV was not reached, which was significantly longer than that of those without a response to EV (11.6 months, p=0.003). In 26 patients with single-organ metastasis of non-LN, all patients with a response to EV survived, but the median OS of those without a response to EV was 7.0 months (p<0.001). In 57 patients with multiple-organ metastases, 39, 11, and 9 patients had two, three, and more than three-organ metastases, respectively. Among them, the median OS of patients with a response to EV was 15.3 months, which was significantly longer than their counterparts (7.9 months, p<0.001). Furthermore, in 25 patients with multiple-organ metastases and a response to EV, there was no difference in OS between patients with a CR at least one organ and those without a CR in any organs.
Conclusions
The response to EV is associated with longer survival in u/mUC patients, irrespective of having single or multiple-organ metastases.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
N. Hayakawa: Financial Interests, Personal, Invited Speaker: Astellas Pharma Inc., Daiichi Sankyo Company Ltd, Merck & Company, Inc., Takeda Pharmaceuticals, Nippon Kayaku Co., Ltd. G. Kaneko: Financial Interests, Personal, Invited Speaker: Astellas Pharma Inc. Y. Endo: Financial Interests, Personal, Invited Speaker: Astellas Pharma Inc., Merck & Company, Inc., Nippon Kayaku Co., Ltd. W. Obara: Financial Interests, Personal and Institutional, Research Grant: Astellas Pharma Inc., AstraZeneca, Pfizer Inc., Ono Pharmaceutical, Taiho Pharmaceuticals. Y. Kondo: Financial Interests, Personal, Invited Speaker: Astellas Pharma Inc., Nippon Kayaku Co., Ltd., Bristol Meyers Squibb. E. Kikuchi: Financial Interests, Personal, Invited Speaker: MSD, Bristol, Janssen, Astellas, Merck Biopham, Nippon Kayaku, Pfizer, AstraZeneca; Financial Interests, Personal, Advisory Board: Astellas, MSD, Bristol, Janssen, Merck Biopham; Financial Interests, Institutional, Research Grant: Takeda, Nippon Kayaku, Kyorin, Taiho, Nippon Shinyaku. All other authors have declared no conflicts of interest.