©2021 GlycoMimetics, Inc. All rights reserved. Glycobiology-based therapeuticsTransforming livesOctober 2022 Corporate Presentation NASDAQ: GLYC

•To the extent that statements contained in this presentation are not descriptions of historical facts, they are forward-looking statements reflecting the current beliefs and expectations of the management of GlycoMimetics, Inc. (“GlycoMimetics,” “we,” “us,” or “our”). Forward-looking statements contained in this presentation may include, but are not limited to: (i) the expected or projected timing of events and data readout from ongoing Phase 3 clinical trials of uproleselan; (ii) the planned or potential clinical development and potential benefits and impact of our drug candidates, including uproleselan; (iii) the timing of receipt of clinical data for our drug candidates; (iv) the potential safety, efficacy or clinical utility of our drug candidates; (v) the size of patient populations targeted by drug candidates we or our collaborators develop,and market adoption of our potential drug candidates by payors, physicians and patients; (vi) the likelihood and timing of regulatory filings, approvals or other anticipated interactions with regulatory authorities; (vii) our business and product development strategies, including our cash needs and expected cash runway; and (viii) any other statement containing terminology such as “may,” “will,” “should,” “expects,” “plans,”“anticipates,” “believes,” “estimates,” “predicts,” “potential,” “intends,” or “continue,” or the negative of these terms or other comparable terminology. •Forward-looking statements are subject to known and unknown risks, uncertainties, and other factors that may cause our or our industry’s actual results, levels of activity, performance, or achievements to be materially different from those discussed, implied or otherwise anticipated by such statements. You are cautioned not to place undue reliance on such forward-looking statements, which are current only as of the date of this presentation. Examples of risks, uncertainties and factors that may cause differences between our expectations and actual results include unexpected safety or efficacy data, unexpected side effects observed during preclinical studies or in clinical trials, lower than expected enrollment rates in clinical trials, whether results of early clinical trials will be indicative of results from later clinical trials, changes in expected or existing competition or additional market research that may cause our expectations about market opportunity to change, changes in the regulatory environment for our drug candidates, failure of our collaborators to support or advance our collaborations or drugcandidates, our need for future capital, the inability to protect our intellectual property, and the risk that we become a party to unexpected litigation or other disputes. For a further description of the risks associated with forward-looking statements, as well as other risks facing GlycoMimetics, please see the risk factors described in the Company’s Annual Report on Form 10-K filed with the U.S. Securities and Exchange Commission on March 3, 2022, as well as other reports we file with the U.S. Securities and Exchange Commission from time to time, including thosefactors discussed under the caption “Risk Factors” in such filings. Forward-looking statements speak only as of the date of this presentation, andGlycoMimeticsundertakes no obligation to update or revise these statements, except as may be required by law.Forward Looking StatementsOctober 20222

Pioneers in glycobiology-based therapies for cancers and other rare diseasesStrongFoundation with Near-Term Catalysts and Broad Pipeline Uproleselan: Multiple Late-Stage Clinical Trials•Fully enrolled Phase 3 trial in R/R AML (n=388), OS events trigger currently projected for mid-2023•Fully enrolled Phase 2 trial in front-line AML (n=267) ongoing, NCI-sponsored•Ongoing ISTs in other AML populations•Novel MOA potential broad utility withBreakthrough Therapy, Fast Track, and Orphandesignations Broad Early-Stage Pipeline•Novel small molecules inhibit carbohydrate signaling•GMI-1687 •Targets sickle cell pain crises•Cleared FDA 30-day IND review •GMI-2093•Targeting fibrotic diseases•First oral Galectin-3 antagonist Targeted Operational Execution •4 Key Leadership Hires in Last Year purpose-driven biotechnology team•Deep expertise in regulatory, medical and commercialization across hem/onctherapies October 20223

•Edwin Rock, MD, PhD –Chief Medical Officer•Prior CMO at Partner Therapeutics,VP at MacroGenics, Clinical project leader for successful BLA of margetuximab. Ex-Astex, Otsuka, GSK•Former FDA Medical Officer, serving as medical reviewer for >50 active INDs and 7 approved anticancer drugs•Prior buyside analyst at LeerinkSwann and Company, reporting to Jeffrey Leerink•Bruce Johnson –Chief Commercial Officer •Former VP, Global Head Malignant Hematology, Novartis and Former VP and Head, Global Commercial Development, AbbVie•>10 launches at the Global, US or regional level including Rydapt, Jakavi, Tasignaand Zometa•Led lifecycle management and portfolio strategy for Venetoclax•Lisa DeLuca, PhD –Vice President, Regulatory Affairs and Quality Assurance•Former VP, Regulatory Affairs at Celator Pharmaceuticals responsible for taking Vyxeosthrough clinical development, manufacturing optimization, NDA preparation, and the acquisition by Jazz Pharmaceuticals•>27 years in Regulatory Affairs at both large pharma and small biotech companies working across multiple solid and liquid tumor types, including AML•Deepak Tiwari, PhD –Vice President, Technical Operations•Former VP and Head of CMC Operations at Rafael Pharmaceutical working on development of devimistatin multiple indications including R/R AML•>25 years experience in both large and small molecules, including pre-formulation, formulation development, analytical characterization, process development, scale-up, technology transfer and process validation.October202244 leadership hires in last 12 months to build team with commercialization expertise

Unmet need continues to be high in AML, with low survival rates1.Short, Rytting, and Cortes. Lancet 2018; 392: 593–606;2.American Cancer Society, AML Key Statistics (accessed April 2022);3.American Caner Society Cancer Facts & Figures 2022, 5-year age-adjusted relative survival rates4.Gattaet al., Burden and centralised treatment in Europe of rare tumours: results of RARECAREnet –a population-based study. Lancet Oncol. 2017, doi: 10.1016/S1470-2045(17)30445-X. 5.Blood cancer UK, Facts and information about blood cancer, August 2019 (accessed April 2022)6.Megías-VericatJE et al. Salvage regimens using conventional chemotherapy agents for relapsed/refractory adult AML patients: a systematic literature review, Ann Hematol. 2018;5 AML is a heterogeneous malignant disorder of hemopoietic stem cells1 Aggressive, rapidly progressive, and fatal if untreated 20k new cases>11k deaths / year AML has lowest survival rate of all leukemias Low 5-year survival rate: <30% in US3and Europe4 vs. >85%for CML/CLL5 Survival across all ages and risk groups is poor, particularly in R/R AML patients Overall survival in R/R AML measured in months62022 Estimated AML Statistics for the US2October2022One of the most common types of leukemia

6 E-selectin:Adhesion molecule constitutively expressed in bone marrow microvasculatureUp-regulated by Leukemic Stem Cells and AML blasts via secreted inflammatory mediators CD62EUproleselan: First-in-Class E-Selectin Antagonist to Address Resistance Pathways in AML Uproleselan, an E-Selectin Antagonist:Releases AML blasts from vascular sequestration, agnostic to AML mutational status Disrupts NF-kB mediated chemoresistance pathwaysPotentialbroad utility across AML E-selectin/E-selectin Ligand Interaction:Enables AML blast sequestration in bone marrow Activates pro-survival NF-kB pathwaysE-selectin ligand sLexup-regulated on AML cells via multiple distinct drug resistance mechanismsOctober2022

October 20227February 2022 Blood data with corresponding commentary by MD Anderson experts highlight uproleselanearly clinical activityPhase 1/2 study of uproleselanadded to salvage chemotherapy for relapsed or refractory AML

•Meta-analysis of 81 studies (N >11,000)•MRD negativity prognostic forsuperior OS•Average OS MRD HR 0.36•Independent of age, subtype,timing,methodMinimal Residual Disease (MRD) negativity and hematopoietic stem cell transplantation (HSCT) both favorably prognosticOctober 20228Short, et al. JAMA Oncology2020 6(12): 1890-1899 OverallSurvivalby MRD status •UproleselanPhase 1/2 overall survival by HSCT •N=54 R/R AML patients at 10 mg/kg RP2D•10 longest survivors all MRD-negative•Overall MRD-negative: 56% 1L, 69% R/RDeAngelo et al, Blood 2022 139(8):1135-1146. OverallSurvivalby HSCT

UPROLESELANRelapsed / Refractory AML Phase 3 Study Design KEY ELIGIBILITY•AML•primary refractory or•first or second relapse•≥18 and ≤75 years in age •Eligible for intensive chemo•< 1 prior HSCT Placebo plus MEC or FAI (n=190) Placebo plus HiDAC or IDAC Uproleselan plus MEC or FAI(n=190) Uproleselanplus HiDAC or IDAC1:1 Randomization (stratified by age, disease status and backbone chemo)Induction(1 Cycle)Consolidation(Up to 3 Cycles) Follow-Up for Overall SurvivalMEC: Mitoxantrone, etoposide and cytarabine FAI: Fludarabine, cytarabine and idarubicin HiDAC/IDAC: High-or Intermediate-dose cytarabine Randomize 1:1(N=380) Overall survival not censored for transplant•90% power to detect Hazard ratio of 0.68 with one-sided 0.025 Type I error rate•Total of 388 patients were enrolled in the trial as of November 2021PRIMARY ENDPOINT 9October 2022

10UPROLESELANPhase 3 Patient Characteristics Mostly Comparable to Phase 2 Relapsed/Refractory Patient Demographics301 StudyN=388201 StudyN=66Age, median (range)58 (20-75)59 (26-84)Refractory, n (%)130 (33.5%)22 (33%)Relapsed, n (%)258 (66.5%)44 (67%)Duration of prior remission ≤6 mos49 (19%)18 (41%)Prior TherapiesHSCT70 (18%)12 (18%)≥2 Induction Regimens63 (16%)22 (33%)ELN Risk CategoryAdverse40%50%Intermediate21%17%Favorable22%11%Unknown17%22%October 2022

10%20%30%40%50%60%70%80%90%RCTProspective cohort study Retrospective study Phase I or II study Note: outcomes with intensive chemotherapy may be heavily impacted by patient characteristics including age, ELN risk, disease status and prior therapy, and that patient numbers are small for some of the data shown. Size of bubble is proportional to sample size. 18mo16mo 14mo 12mo 10mo 8mo 6mo 4mo2mo 0% Median OSHSCT Rates Single center (Italy); N=55; 51y Single center (Germany); N=132; 52y AlloHSCTrates in R/R AML are highly variable and depend largely on efficacy of salvage regimen and patient/disease characteristics. Intensive Chemotherapy (IC) in R/R AML Typical ~6-7 months mOSand HSCT rates ~25-30%October 202211

5.2 3.36.35.46.87.70246 8101214Lintuzumab + MEC vs. MECElacytarabine vs. Inv. ChoiceIDAC +clofarabine vs IDACGuadecitadine vs Inv. choiceVarious salvage regimensIdasanutlin + IDAC vs. IDAC UproPhase 1/2 ≈ 8.8 mos.1 October202212Historical Intensive Chemotherapy benchmarks for mOSare ~6 monthsPhase 3, RCTN=97Feldman et al, JCO 2005Phase 3, RCTN=191Robozet al, JCO 20143Phase 3, RCTN=157Faderlet al, JCO 2011Retrospective ReviewN=850+ 4Megias-Vericatet al, Ann Hematol2018Phase 3, RCTN=154Robozet al, Blood 20213Phase 3, RCTN=146Konoplevaet al, Blood Advances 2022mOS Historical IC benchmark ≈ 6 mos.2Note: patient outcomes for IC eligible populations often vary depending upon patient and disease characteristics1 Follow-up period cutoff at 9.7 mons to focus on Phase 3. 15 patients (28%) in RP2D population were censored for OS2 Historical OS reflects control arms3 Control group includes patients on MEC and FLAG-IDA4 All patients in this analysis received MEC

Duration of Follow-Up and Outcomes in Key AML TrialsOctober 202213 Sanofi –Clofarabine(CLASSIC I Trial) Roche –Idasanutlin(MIRROS Trial) Astellas -XOSPATA (Gilteritinib) –ADMIRAL Trial Jazz -VYXEOS (CPX-351)6.2 mos6.7 mos17.8 mos20.7 mos Succeeded on OSFailed on OS Uproleselan301 TrialCurrent projected events trigger mid-2023≥19 months median follow-up (as of September 15, 2022) Clavis–Elacytarabine(CLAVELA Trial ) Sunesis–Vosaroxin(VALOR Trial) <6 mos*~6 mos*R/RN=388R/RN=447R/RN~320R/RN=711R/RN=381FLT3+ R/RN=371sAMLN=309* Median follow-up derived from protocol and/or final results as it was not included in the publication

GMI-1687 Potential on-demand treatment for SCD Acute VOC

Significant Unmet Need Remains in SCD15 Prevalence~100K SCD patients in the US~1 in 365 Black Americans affected at birth25-30yrReduction in average life expectancy SymptomsVaso-occlusive crises (VOCs), also referred to as pain crises, arethe clinical hallmark of SCD>90%of hospitalizations due to VOC↑Risk of StrokeAcute Chest Syndrome Renal failure Treatments<1 VOC improvement per yr(From 3.19 to 2.77 VOCs/yr) Centers for Disease Control and Prevention. Sickle cell disease (SCD) accessed May 4, 2021 LanzkronS, et al. Pub Health Rep. 2013;128:110-116. Ballas, S.K. American Journal of Hematology DOI: 10.1002/ajh.21443. Centers for Disease Control and Prevention. Sickle cell disease (SCD) accessed Aug, 2022; Sins JWR, et al.,.Blood Adv. 2017;1(19):1598–616~1 VOC improvement per yr(From 3 to 1.6 VOCs/yr) October 2022VoxeletorCrizanlizumab-tmca

Even with Prophylactic and Gene Therapy Approaches, Acute VOC Will Remain A Significant Unmet Medical Need16 Prophylactic Therapies (Approved & Selected In Development) 220,000 –450,000 VOCs/year(in the era of prophylactic therapies)Dampier et al. 2017 American Society of Hematology Annual Meeting. Abstract# 4660.N EnglJ Med 2019; 381:509-51; N EnglJ Med 2017; 376:429-439 SUBCLINICALOngoing, Silent VOCs0-1 VOC CLINICALLY VISIBLE VOCs2-5 VOCs6+ VOCs 20%50%30%30% reduction in VOC(ASH 2021 Real World Data)50% reduction in VOC45% reduction in VOC(SUSTAIN Study)Gene Therapies (Selected In Development) E-selectin mAb(Phase 1)P-selectin mAb(Likely 45% reduction in VOC)PF-07209326 (Pfizer) Vertex/CRISPREXA-CEL EDITASEDIT-301 On-Demand Acute VOC Therapies (Selected In Development)IntelliaBCL11ASangamoBCL11A GMI-1687 E-selectin antagonist Use impacted by disparities in access to care, socioeconomic factors and toxicity (e.g. HU-myelosuppression; Advakeo–liver pathologies)October 2022VoxeletorHydroxyurea InclacumabCrizanlizumab-tmca

October 2022For patients treated within first quartile of treatment timeliness (< 26.4hrs), a meaningful, statistically significant benefit was seen across study endpointsRESETEarly Intervention Resulted In Clinical Benefit 17 TTRD = time to readiness for discharge; TTD = time to discharge; TTDIVO = time to discontinuation of IV opioids; CIVO = cumulative IV opioid useT. Wun, ASH 2020

October 2022181 Morikis et al, Frontiers in Immunology, April 2021, Vol. 12, Article 663886GMI-1687 leverages years of research to empower patients to take control of their disease Lessons LearnedGMI-1687 E-selectin drives acute VOC1•Fast-acting, small molecule inhibitor against E-selectin to block endothelial activation and multicellular adhesion that are the foundation of acute VOC•> 500-fold more potent than rivipanselTreatment early during VOC is critical •Patients (or caregiver) can potentially self-administerGMI-1687 via an autoinjector upon recognition of an acute VOC episode •100% bioavailable following subcutaneous administration Too little, too late -must give full doses•Optimize dose and regimen based on reductions in sE-selectin –drive and sustain •Agreed to as part of FDA Pre-IND Meeting Potentially changing the treatment paradigm to convenient, early, on-demand disease modifying therapy FDA “Safe to Proceed” Clearance for IND in June 2022