Background: FGFR2/3, MTAP and ERBB2 genomic alterations have treatment targets in advanced urothelial carcinoma (aUC). These alterations may affect tumor microenvironment and outcomes with immune checkpoint inhibitors (ICIs) in aUC., Patients and Methods: We identified patients with available genomic data in our multi-institution cohort of patients with aUC treated with ICI. Outcomes (observed response rate [ORR], progression-free and overall survival [PFS, OS]) with ICI were compared between patients with and without FGFR 2/3, MTAP, ERBB2 alterations. We compared ORR using logistic regression and PFS/OS using Cox proportional hazards., Results: Out of 1,514 patients, 276 (18%), 174 (11%) and 208 (14%) patients had known FGFR2/3, MTAP and ERBB2 alteration status, respectively. and were treated with ICI in 1L or 2 + L. In patients with (vs. without) FGFR2/3 alteration, ORR with ICI was 21% vs. 32% (OR 0.54; [95%CI 0.32-0.91]), PFS was significantly shorter in patients with FGFR2/3 alterations (HR = 1.36 [95%CI 1.03-1.80]; P=0.03); OS was not significantly different (HR = 1.22 [95%CI 0.86-1.47]). In patients with (vs. without) MTAP alteration, ORR with ICI was 25% versus 40% (OR 0.52 [95%CI 0.20-1.38]); PFS and OS were nonsignificantly different. In patients with (vs. without) ERBB2 alteration, ORR with ICI was similar (37% vs. 35%; OR 1.06; 95%CI 0.57-1.97); PFS and OS were significantly longer in patients with ERBB2 alteration [HR 0.63 (95%CI 0.41-0.95); P=0.03; HR 0.66, [95% CI 0.44-0.97]), respectively., Conclusion: Our results support further evaluation of FGFR2/3, MTAP and ERBB2 alterations as putative biomarkers in patients with aUC treated with ICI., Competing Interests: Disclosure Rafee Talukder, Dimitra Rafailia Bakaloudi, Dimitrios Makrakis, Leonidas N. Diamantopoulos, Thomas Enright, Jacob Leary, Ruben Raychaudhuri, Nishita Tripathi, Tanya Jindal, Charles B. Nguyen, Roubini Zakopoulou, Aristotelis Bamias, David Marmorejo, David J Pinato, James Korolewicz,Lucia Alonso Buznego, Clara Castro Carballeira, Tyler F. Stewart, Pedro Barata, Vadim S. Koshkin: No conflicts to disclosure. Neeraj Agarwal (lifetime disclosures): No personal COIs since April 15, 2021. Consultancy to Astellas, Astra Zeneca, Aveo, Bayer, Bristol Myers Squibb, Calithera, Clovis, Eisai, Eli Lilly, EMD Serono, Exelixis, Foundation Medicine, Genentech, Gilead, Janssen, Merck, MEI Pharma, Nektar, Novartis, Pfizer, Pharmacyclics, and Seattle Genetics. Research funding to Neeraj Agarwal's institution: Arnivas, Astellas, Astra Zeneca, Bavarian Nordic, Bayer, Bristol Myers Squibb, Calithera, Celldex, Clovis, Crispr, Eisai, Eli Lilly, EMD Serono, Exelixis, Genentech, Gilead, Glaxo Smith Kline, Immunomedics, Janssen, Lava, Medivation, Merck, Nektar, Neoleukin, New Link Genetics, Novartis, Oric, Pfizer, Prometheus, Rexahn, Roche, Sanofi, Seattle Genetics, Takeda, and Tracon. Jason R. Brown: Received funding from EMD–Serono for a Speaker's Bureau. Yousef Zakharia: Advisory Board: Bristol Myers Squibb, Amgen, Roche Diagnostics, Novartis, Janssen, Eisai, Exelixis, Castle Bioscience, Genzyme Corporation, Astrazeneca, Array, Bayer, Pfizer, Clovis, EMD serono, Myovant. Grant/research support from: Institution clinical trial support from NewLink Genetics, Pfizer, Exelixis, Eisai. DSMC: Janssen Research and Development.Consultant honorarium: Pfizer, Novartis. Alexandra Drakaki has served as consultant for Bristol–Myers Squibb, AstraZeneca, RADMETRIX, Seattle Genetics, Janssen, PACT Pharma, Merck, Roche/Genentech, Exelixis, Dyania Health, has received research funding from Kite/Gilead, AstraZeneca, Genentech/Roche, BMS, Merck Sharp & Dohme, Jounce Therapeutics, Infinity Pharmaceuticals, Seattle Genetics/Astellas, and has received travel expenses from Lilly, AstraZeneca and Seattle Genetics. Ignacio Duran: Research Grant to institution: Roche, AstraZeneca, Honoraria: Bristol Myers Squibb, MSD, Ipsen, Roche–Genentech, Janssen, Astellas Pharma, EUSA Pharma, Bayer, Novartis, Gilead, Bayer. Support for attending meetings and/or travel: Merck–Pfizer, Ipsen, Jansen, Bayer, AstraZeneca. Advisory board: Bristol Myers Squibb, MSD, Ipsen, Roche–Genentech, Astellas Pharma, EUSA Pharma, Bayer, Novartis, Eisai, Debio Pharma, Pharmacyclycs, Gilead. Rafael Morales–Barrera has served as consultant/advisor for Sanofi, AstraZeneca, Astellas Pharma and MSD, has been in the speaker's Bureau for Astellas Pharma, Merck/Pfizer and MSD Oncology, and has received travel accommodations from Sanofi, Pfizer, MSD, Astellas Pharma, Astra Zeneca, Bayer, Roche/Genentech. Macarena Rey–Cárdenas: Pfizer, Bayer. Pfizer; Pierre Fabre; Ipsen; BMS; AstraZeneca; MSD; Roche; Kyowa Kirin; Accord. Daniel Castellano: Consulting or Advisory Role: Janseen Oncology, Roche/Genentech, Astellas Pharma, AstraZeneca, Pfizer, Novartis, Ipsen, Bristol–Myers Squibb, MSD Oncology, Bayer, Lilly, Sanofi, Pierre Fabre, Bpehringer Ingelheim. Research funding: Janseen Oncology. Travel, Accomondations, Expenses: Pfizer, Roche, Bristol–Myers Squibb, AstraZeneca Spain. Ajjai Alva: Dr. Ajjai Alva serves as a consultant for Merck, AstraZeneca, Bristol–Myers Squibb, and Pfizer/EMD Serono. Dr. Ajjai Alva receives research funding through the University of Michigan from Merck, Genentech, Prometheus Laboratories, Mirati Therapeutics, Roche, Bayer, Progenics, Astellas Pharma, Arcus Biosciences, AstraZeneca, Bristol–Myers Squibb, and Clovis Oncology. Rana R. McKay: Consulting/Advisory Board – Aveo, AstraZeneca, Bayer, Bristol Myers Squib, Calithera, Caris, Denderon, Exelixis, Esiai, Janssen, Lilly, Merck, Myovant, Novartis, Pfizer, Sanofi, SeaGen, Sorrento Therapeutics, Telix, Tempus. Institutional Research Funding – Bayer, Tempus, AstraZeneca, Oncternal, Exelixis, BMS. Tyler Stewart: Advisory Board/Consulting- Seagen/Astellas, AstraZeneca and received research support from GRAIL. Shilpa Gupta has received personal fees from Bristol Myers Squibb, Merck, Janssen, Seattle Genetics, EMD Sorono and Pfizer, and has received grants from Astellas, BMS and Bristol Myers Squibb. Evan Yu: Consulting fees from Aadi Bioscience, Advanced Accelerator Applications, Bayer, Janssen, Merck, Oncternal. Research funding to institution from Bayer, Blue Earth, Daiichi–Sankyo, Dendreon, Lantheus, Merck, Seagen, Surface, Taiho, Tyra Ali Raza Khaki has received institutional research funding from 23andMe, Janssen, and Pfizer. Petros Grivas: consulting for Aadi Bioscience, Abbvie, Asieris Pharmaceuticals, Astellas, AstraZeneca, Bicycle Therapeutics, Bristol Myers Squibb, CG Oncology, Daiichi Sankyo, EMD Serono, Fresenius Kabi, Gilead, G1 Therapeutics, ImmunityBio, Janssen, MSD, Pfizer, Replimune, Roche, Strata Oncology; research funding: Acrivon Therapeutics, ALX Oncology, Bristol Myers Squibb, EMD Serono, Genentech, Gilead, G1 Therapeutics, Mirati Therapeutics, MSD, QED Therapeutics., (Copyright © 2024 Elsevier Inc. All rights reserved.)