Purpose: To increase awareness, outline strategies, and offer guidance on the recommended management of immune-related adverse events (irAEs) in patients treated with chimeric antigen receptor (CAR) T-cell therapy., Methods: A multidisciplinary panel of medical oncology, neurology, hematology, emergency medicine, nursing, trialists, and advocacy experts was convened to develop the guideline. Guideline development involved a systematic literature review and an informal consensus process. The systematic review focused on evidence published from 2017 to 2021., Results: The systematic review identified 35 eligible publications. Because of the paucity of high-quality evidence, recommendations are based on expert consensus., Recommendations: The multidisciplinary team issued recommendations to aid in the recognition, workup, evaluation, and management of the most common CAR T-cell-related toxicities, including cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, B-cell aplasia, cytopenias, and infections. Management of short-term toxicities associated with CAR T cells begins with supportive care for most patients, but may require pharmacologic interventions for those without adequate response. Management of patients with prolonged or severe CAR T-cell-associated cytokine release syndrome includes treatment with tocilizumab with or without a corticosteroid. On the basis of the potential for rapid decline, patients with moderate to severe immune effector cell-associated neurotoxicity syndrome should be managed with corticosteroids and supportive care.Additional information is available at www.asco.org/supportive-care-guidelines., Competing Interests: Reprint Requests: Bianca D. SantomassoConsulting or Advisory Role: Celgene, Janssen, Legend Biotech, Incyte, In8BioResearch Funding: ADC Therapeutics (Inst) Loretta J. NastoupilHonoraria: Celgene, Gilead Sciences, Novartis, Bayer, Janssen Oncology, Pfizer, Gamida Cell, TG Therapeutics, Bristol Myers Squibb, ADC Therapeutics, Morphosys, Epizyme, GenmabResearch Funding: TG Therapeutics, Janssen Biotech, Celgene, Genentech/Roche, LAM Therapeutics, Epizyme, Novartis, IgM Biosciences, Caribou Biosciences, Gilead Sciences, Allogene Therapeutics, Takeda Sherry AdkinsConsulting or Advisory Role: CelgeneTravel, Accommodations, Expenses: Celgene Bryan J. SchneiderResearch Funding: Merck Milan AnadkatStock and Other Ownership Interests: Anthem, Humana, Perrigo, Walgreens Boots Alliance, Abbott Laboratories, Merck, AbbVie, Amgen, Bristol Myers Squibb, Celgene, CVS Health, Gilead Sciences, Incyte, Johnson & Johnson, Lilly, Medtronic, Mylan, Pfizer, Procter & Gamble, United Health Group, Regeneron, Roche, Moderna Therapeutics, Dexcom, Quest DiagnosticsHonoraria: Adgero Biopharmaceuticals, Boehringer Ingelheim, Novocure, AbbVie, UCB, InnovadermConsulting or Advisory Role: Adgero Biopharmaceuticals, Boehringer Ingelheim, Novocure, Kintara TherapeuticsResearch Funding: AnaptysBio, Boehringer Ingelheim, Biogen, InflaRx, Lutris, Novartis, OnQuality Pharmaceuticals, Veloce Pharmaceuticals, XBiotech, UCB, AbbVie, Lilly Michael B. AtkinsStock and Other Ownership Interests: Werewolf Pharma, PyxisConsulting or Advisory Role: Genentech, Novartis, Bristol Myers Squibb, Merck, Exelixis, Eisai, Agenus, Arrowhead Pharmaceuticals, Werewolf Pharma, Surface Oncology, Iovance Biotherapeutics, Pyxis, Pneuma Respiratory, Leads Biolabs, Fathom Biotechnology, Aveo, Cota Healthcare, Neoleukin Therapeutics, Adagene, Idera, Ellipses Pharma, AstraZeneca, PACT Pharma, Seattle Genetics, Pfizer, Scholar Rock, Asher Bio, Calithera Biosciences, Takeda, SanofiResearch Funding: Bristol Myers Squibb Kelly J. BrassilEmployment: Pack HealthHonoraria: Oncology Nursing Society, WebMD, M Consulting, i3 HealthResearch Funding: AbbVie, Daiichi Sankyo, Astellas Pharma, Genentech, Sanofi, GlaxoSmithKlineTravel, Accommodations, Expenses: Pack Health Jeffrey M. CaterinoStock and Other Ownership Interests: Motive Medical IntelligenceConsulting or Advisory Role: Wellstat TherapeuticsResearch Funding: Stago, Entegrion, JDP Therapeutics, AstraZeneca Ian ChauHonoraria: Lilly, Eisai, ServierConsulting or Advisory Role: Lilly, Bristol Myers Squibb, MSD Oncology, Merck Serono, Roche/Genentech, AstraZeneca, Pierre Fabre, Boehringer Ingelheim, Incyte, OncXerna Therapeutics, Astellas Pharma, GlaxoSmithKline, Eisai, SotioResearch Funding: Janssen-Cilag, LillyTravel, Accommodations, Expenses: MSD, Merck Serono, Lilly, Bristol Myers Squibb, Eisai Marianne J. DaviesSpeakers' Bureau: AstraZeneca, Genentech/Roche, Merck, Bristol Myers Squibb Marc S. ErnstoffStock and Other Ownership Interests: GE Healthcare, Bristol Myers SquibbResearch Funding: Alkermes, EMD SeronoTravel, Accommodations, Expenses: ImmuNext, AlkermesOther Relationship: Bristol Myers Squibb Leslie FecherConsulting or Advisory Role: Via Oncology, Hoosier Cancer Research Network, ElsevierResearch Funding: Merck, Incyte, Bristol Myers Squibb, Pfizer/EMD Serono, Array BioPharma, Kartos TherapeuticsOther Relationship: Array BioPharmaUncompensated Relationships: NCCN, American Association of Clinical Endocrinology, ASCO Pauline FunchainConsulting or Advisory Role: EisaiResearch Funding: Pfizer, Bristol Myers Squibb, Taiho Oncology Jennifer S. MammenStock and Other Ownership Interests: Johnson & Johnson, Bristol Myers SquibbConsulting or Advisory Role: Five Prime Therapeutics Jarushka NaidooHonoraria: Bristol Myers Squibb, AstraZeneca/MedImmune, Merck, Daiichi Sankyo/Lilly, TakedaConsulting or Advisory Role: Bristol Myers Squibb, AstraZeneca/MedImmune, Roche/Genentech, Daiichi Sankyo/Lilly, Takeda, Pfizer, Kaleido BiosciencesResearch Funding: Merck, AstraZeneca, Roche/GenentechTravel, Accommodations, Expenses: Bristol Myers Squibb, AstraZeneca/MedImmune Aung NaingConsulting or Advisory Role: Novartis, CytomX Therapeutics, OncoSec, STCube Pharmaceuticals Inc, Kymab, Takeda (I), CSL Behring (I), Horizon Pharma (I), Genome & CompanyResearch Funding: NCI, EMD Serono, MedImmune, Atterocor, Amplimmune, ARMO BioSciences, Karyopharm Therapeutics, Incyte, Novartis, Regeneron, Merck, Bristol Myers Squibb, Pfizer, CytomX Therapeutics, Neon Therapeutics, Calithera Biosciences, TopAlliance BioSciences Inc, Healios, Lilly, Kymab, PsiOxus Therapeutics, Immune Deficiency Foundation (I), Arcus Biosciences, NeoImmuneTech, ImmuneOncia, Surface Oncology, Baxalta (I), Jeffrey Modell Foundation (I), Chao Physician-Scientist AwardsTravel, Accommodations, Expenses: ARMO BioSciences Tanyanika PhillipsTravel, Accommodations, Expenses: City of Hope Alexander SpiraLeadership: NEXT Oncology VirginiaStock and Other Ownership Interests: Eli LillyHonoraria: CytomX Therapeutics, AstraZeneca/MedImmune, Merck, Takeda, Amgen, Janssen Oncology, Novartis, Bristol Myers Squibb, BayerConsulting or Advisory Role: Array BioPharma (Inst), Incyte, Amgen, Novartis, AstraZeneca/MedImmune (Inst), Mirati Therapeutics, Gritstone Oncology, Jazz Pharmaceuticals, Merck (Inst), Bristol Myers Squibb (Inst), Takeda, Janssen Research & DevelopmentResearch Funding: Roche (Inst), AstraZeneca (Inst), Boehringer Ingelheim (Inst), Astellas Pharma (Inst), MedImmune (Inst), Novartis (Inst), Newlink Genetics (Inst), Incyte (Inst), AbbVie (Inst), Ignyta (Inst), LAM Therapeutics (Inst), Trovagene (Inst), Takeda (Inst), Macrogenics (Inst), CytomX Therapeutics (Inst), LAM Therapeutics (Inst), Astex Pharmaceuticals (Inst), Bristol Myers Squibb (Inst), Loxo (Inst), Arch Therapeutics (Inst), Gritstone (Inst), Plexxikon (Inst), Amgen (Inst), Loxo (Inst), Daiichi Sankyo (Inst), ADCT (Inst), Janssen Oncology (Inst), Mirati Therapeutics (Inst), Rubius (Inst) Maria Suarez-AlmazorConsulting or Advisory Role: Agile Therapeutics, AMAG Pharmaceuticals¸ Abbvie/Genentech, Avenue Therapeutics, Gilead Sciences, ChemoCentryx, Celgene/Bristol Myers Squibb Umang SwamiConsulting or Advisory Role: Seattle Genetics John A. ThompsonConsulting or Advisory Role: Calithera Biosciences, Clinical Care Options/NCCN, BJ Bioscience, Alpine Immune Sciences, Neoleukin Therapeutics, Academy for Continued Healthcare Learning, Meeting Sites Pro, Regeneron, AVEO, Bristol Myers SquibbResearch Funding: Roche, Pfizer, Agensys, Five Prime Therapeutics, Trillium Therapeutics, Merck, Novartis, Xencor, Five Prime Therapeutics, Incyte Praveen VikasStock and Other Ownership Interests: NovavaxResearch Funding: Sanofi Yinghong WangConsulting or Advisory Role: Tillotts Pharma, Azurrx Pharma Jeffrey S. WeberStock and Other Ownership Interests: CytomX Therapeutics, Biond, Protean Biodiagnostics, NeximmuneHonoraria: Bristol Myers Squibb, Merck, Genentech, AstraZeneca, Daiichi Sankyo, GlaxoSmithKline, Amgen, Roche, Celldex, CytomX Therapeutics, Novartis, Sellas Life Sciences, WindMIL, Takeda, Moderna Therapeutics, Jounce Therapeutics, Kirin Pharmaceuticals, Regeneron, Idera, OncosecConsulting or Advisory Role: Celldex, Bristol Myers Squibb, Merck¸ Genentech, Roche, Amgen, AstraZeneca, GlaxoSmithKline, Daiichi Sankyo, CytomX Therapeutics, Novartis, Sellas Life Sciences, WindMIL, Jounce Therapeutics, Moderna Therapeutics, Kirin Pharmaceuticals, Protean Biodiagnostics, Idera, OncosecResearch Funding: Bristol Myers Squibb, Merck, GlaxoSmithKline, Genentech, Astellas Pharma, Incyte, Roche, Novartis, NextCure (Inst), Moderna Therapeutics (Inst)Patents, Royalties, Other Intellectual Property: Named on a patent submitted by Moffitt Cancer Center for an IPILIMUMAB biomarker, named on a patent from Biodesix for a PD-1 antibody biomarker, and named on a patent for 41BB-induced TIL by Moffitt Cancer CenterTravel, Accommodations, Expenses: Bristol Myers Squibb, GlaxoSmithKline, Roche, Celldex, Amgen, Merck, AstraZeneca, Genentech, Novartis Monalisa GhoshResearch Funding: Celgene (Inst)No other potential conflicts of interest were reported.