%0 Journal Article
%T PD-1 inhibition with retifanlimab and/or arginase inhibition with INCB001158 in Japanese patients with solid tumors: A phase I study.
%A Kuboki Y
%A Koyama T
%A Matsubara N
%A Naito Y
%A Kondo S
%A Harano K
%A Yonemori K
%A Yoh K
%A Gu Y
%A Mita T
%A Chen X
%A Ueda E
%A Yamamoto N
%A Doi T
%A Shimizu T
%J Cancer Med
%V 13
%N 8
%D 2024 Apr
%M 38651187
%F 4.711
%R 10.1002/cam4.6980
%X <B>BACKGROUND: </B>Retifanlimab is a humanized monoclonal antibody targeting programmed death protein-1, and INCB001158 is an oral arginase inhibitor. This phase Ib study investigated retifanlimab, INCB001158, and their combination in Japanese patients with advanced solid tumors.<BR><B>METHODS: </B>Patients received retifanlimab (500 mg every 4 weeks [Q4W] i.v.) or escalating doses of INCB001158 (75 or 100 mg twice daily [BID]) monotherapy in Part 1 and combination of retifanlimab (500 mg Q4W) and INCB001158 (100 mg BID) in Part 2. Primary endpoints were safety, tolerability, dose-limiting toxicities (DLTs), and determination of recommended phase II doses in Japanese patients.<BR><B>RESULTS: </B>Eighteen patients (retifanlimab or INCB001158 monotherapy and combination; n = 6 each) were enrolled at 2 sites in Japan. There were no DLTs, fatal adverse events (AEs), or discontinuations due to AEs. Rash (all grade 1) was the most common treatment-emergent AE with retifanlimab (n = 6). Treatment-related AEs were reported with retifanlimab (n = 4) or INCB001158 (n = 2) monotherapy and with combination (n = 4); an immune-related AE (thyroid disorder, grade 2) was reported with combination. Two responses were observed with retifanlimab monotherapy (1 complete, 1 partial) and 1 stable disease (SD), for an overall response rate of 33.3% (95% confidence interval [CI], 4.3-77.7) and disease control rate (DCR) of 50% (95% CI, 11.8-88.2). Three patients had SD with INCB001158 monotherapy (DCR 50%; 95% CI, 11.8-88.2). No responses or SD were observed with combination therapy.<BR><B>CONCLUSIONS: </B>Retifanlimab, INCB001158, and their combination had acceptable safety profiles. Promising retifanlimab antitumor activity warrants further investigation in Japanese patients.