Abstract 289P
Background
Maintenance avelumab (mAve) is recommended for patients with unresectable, metastatic, advanced urothelial carcinoma (aUC) achieving at least stable disease (SD) on first-line platinum-based chemotherapy (1L-PCT). However, second-line pembrolizumab monotherapy (2L-Pem) is an alternative therapeutic avenue for this patient cohort in real-world clinical practice. We investigated real-world data, addressing the correlation between response to 1L-PCT and survival of following immune checkpoint inhibitor (ICI) therapy with mAve or 2L-Pem.
Methods
A multicenter database registered 172 patients who showed partial response (PR) or SD to 2-6 cycles of 1L-PCT and treated by subsequent ICI therapy. Pembrolizumab monotherapy was not approved as maintenance setting after 1L-PCT in Japan. 2L-Pem patients were followed-up without any systemic treatment after completion of the planned 1L-PCT or discontinued 1L-PCT due to intolerable side effects and treated with 2L-Pem after radiographic detection of tumor relapse. Patients were categorized based on response to 1L-PCT using the Response Evaluation Criteria in Solid Tumors (v1.1) into three subgroups: PR (response, -30% or less), SD (response, from -29% to +19%), favorable SD (tumor shrinkage, from -29% to 0%), and unfavorable SD (tumor enlargement, from +1% to +19%) groups. Objective response rate, progression to ICI-free survival (ICI-PFS), and overall survival from start of 1L-PCT were compared between 34 patients treated with mAVe and 138 patients treated with 2L-Pem in each response subgroup.
Results
Objective response rate was higher and ICI-PFS was longer in patients achieving PR or SD on 1L-PCT and subsequently receiving 2L-Pem compared to those receiving mAve. In contrast, overall survival did not differ between patients treated with mAve versus 2L-Pem. Similar findings were discerned in the subanalysis of patients having favorable SD and unfavorable SD on 1L-PCT.
Conclusions
The finding provides real-world evidence regarding difference of oncological efficacy between subsequent mAve and 2L-Pem in patients with aUC who achieved PR or SD on 1L-PCT.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
M. Miyake: Financial Interests, Personal and Institutional, Speaker, Consultant, Advisor: Janssen Pharmaceutical K.K., Merck Biopharma Co., Ltd., MSD K.K., Ono Pharmaceutical Co., Ltd., Astellas Pharma Inc., AstraZeneca K.K., Olympus Corporation, Nippon Kayaku Co., Ltd.; Financial Interests, Personal and Institutional, Research Funding: Marukai Corporation, SBI Pharmaceuticals Co., Ltd. K. Fujimoto: Financial Interests, Personal and Institutional, Speaker, Consultant, Advisor: Merck Biopharma Co., Ltd., MSD K.K., Ono Pharmaceutical Co., Ltd.; Financial Interests, Personal and Institutional, Research Funding: MSD K.K., Ono Pharmaceutical Co., Ltd. All other authors have declared no conflicts of interest.