First-in-class small-molecule anti-fibrotic and anti-cancer agents January 2021 Forward-looking statements This presentation contains forward-looking statements that involve substantial risks and uncertainties. All state

First-in-class small-molecule anti-fibrotic and anti-cancer agents January 2021

Forward-looking statements This presentation contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, contained in this presentation, including statements regarding Galecto, Inc.'s (the "Company") strategy, future operations, future financial position, projected costs, prospects, plans, and objectives of management, are forward-looking statements. The words anticipate,'' believe,'' continue,'' could,'' estimate,'' expect,'' intend,'' may,'' plan,'' potential,'' predict,'' project,'' target,'' should,'' would,'' and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. For such statements, we claim the protection of the Private Securities Litigation Reform Act of 1995. The Company may not actually achieve the plans, intentions, or expectations disclosed in these forward-looking statements, and you should not place undue reliance on these forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in these forward-looking statements. Factors that could cause actual results to differ materially from such statements include, without limitation: Drug development is expensive, time consuming, uncertain and susceptible to change, interruption, delay or termination; the timing and outcome of research, development and regulatory review and feedback is uncertain; we expect to need additional funds to advance all of our programs, and you and others may not agree with the manner in which we allocate our resources; the amount of our future losses is uncertain and could cause our stock price to fluctuate or decline; topline data may not accurately reflect the complete results of a particle study or trial; results of clinical trials and other studies are subject to different interpretation and may not be predictive of future results; new data may be unexpected or unfavorable; GB0139, GB1211, GB2064 or other drug candidate may not advance in development or be approve for marketing; clinal trial and other studies may not proceed at the time or in the manner expected or at all; enrolling patients in our ongoing and intended clinical trials is competitive and challenging; the duration and severity of the ongoing coronavirus disease (COVID-19) pandemic, including but not limited to the impact on our clinical and other operations, the operations of our suppliers, others and the capital markets, which in each case remains uncertain; clinical and nonclinical data is voluminous and detailed, and regulatory agency may interpret or weigh the importance of data differently and reach different conclusions than we or others, request additional information, have additional recommendations or change their guidance or requirements; data and information related to our program may not meet regulatory requirements or otherwise be sufficient for further development at all or on our projected timeline; other risks related to developing, seeking regulatory approval of and commercializing drugs, including regulatory, manufacturing, supply and marketing issues and drug availability; our and third parties' intellectual property rights; competition; reimbursement and pricing decisions; risk relating to relying on third parties; product liability and other litigation; and legislation and regulations. Additional factors that could cause results to differ materially from those stated or implied by our forward-looking statements are disclosed in our Securities and Exchange Commission (SEC) filings, including under the headings "Risk Factors." In addition, the forward-looking statements included in this presentation represent the Company's views as of the date of this presentation. The Company anticipates that subsequent events and developments will cause its views to change. However, while the Company may elect to update these forward-looking statements at some point in the future, it specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing the Company's views as of any date subsequent to the date of this presentation.

Investment Highlights 3

start Potentially registrational in US and EU Unique Pipeline Targeting Fibrosis and Cancer 2022 2022 2022 2022 4

Galectin-3 and LOXL2: Targeting Serious Fibrotic Diseases Through Two Different Mechanisms of Action 5 GB0139 and GB1211

(Galectin-3 inhibitors) GB2064

(LOXL2 Inhibitor) Feedback loop Galectin-3 activates macrophages and recruits and activates all key cell types in fibrosis LOXL2 drives cross-linking of collagen, forming the backbone of fibrosis

GB0139: Inhaled Galectin-3 Inhibitor for IPF 6

Approximately 100K patients in US

IPF is a progressive, irreversible, ultimately fatal lung disease characterized by decline in lung function (as measured by FVC)

Lung tissue scars and becomes non-functional

Median survival of 2-5 years

Death caused by respiratory failure

Unknown cause IPF is a Large Orphan Indication with Suboptimal Solutions 7 Only two approved drugs to slow disease progression: Pirfenidone and Nintedanib

Neither has been associated with improvements in overall survival

Both have significant side-effects that limit compliance and usage

Due to side effects, less than 50% of patients on treatment

Despite dose-limiting side effects, sales of pirfenidone and nintedanib in 2019 exceeded $2.8B in the aggregate

Disease Overview Limited Treatment Options

GB0139 Well tolerated in clinical trials and long-term toxicology studies to date

Existing therapies marred by significant side effects leading to approximately 50% discontinuations Unique and pluripotent MoA

GB0139 inhibits fibrosis by targeting macrophages, fibroblasts, and epithelial cells GB0139 reduced macrophage galectin-3 levels in lungs of IPF patients

Dose-response effects on several fibrosis plasma biomarkers

No other therapy in development has demonstrated similar consistent effects Inhaled therapy via generic inhaler delivers therapy directly to target tissue with low systemic exposure

Competing clinical development candidates given intravenously, subcutaneously and orally Superior delivery Pluripotent MoA Well Tolerated Confirmed Target Engagement GB0139: Inhalable, Once-Daily Treatment for IPF

Potential for Accelerated Approval 8

Phase 1 Trial Design

6 dose groups (0.15, 1.5, 3, 10, 20 and 50 mg)

4 active patients and 2 placebos in each group

Key Phase 1 SAD Study Results

Highly reproducible pharmacokinetic (PK) profile and dose-dependent exposure

Mild adverse events (AE) only (cough & headache)

All lab and other clinical parameters satisfactory

Generic inhaler performing well

GB0139: Results of Phase 1 SAD Study 9

24 patients in 3 dose groups

Double-blind, placebo-controlled, multicenter

Doses: 0.3, 3 and 10 mg per day

5 active patients and 3 placebos per group

Four centers in the UK

All patients completed 2 week dosing as planned

Evaluable bronchoalveolar lavages (BALs) obtained for all 48 bronchoscopies

GB0139: Phase 2a Patient Study in IPF Patients 10

GB0139: Phase 2a Result - Bioavailability & Target Engagement in IPF Patients 11 Exceptionally Consistent PK Data in IPF Patients GB0139 Reaches the Alveolar Macrophages Deep within Lung Extracellular Gal-3 Levels

Alveolar Macrophages GB0139 Concentration in Alveolar Macrophages Induces Profound Reduction of Gal-3 Levels on Alveolar Macs

GB0139: Phase 2a Study Showed Consistent, Dose-Dependent Effects on Highly Relevant Fibrosis Biomarkers 12 Biomarkers associated with IPF disease severity and progression had biggest impact

Biomarker effects cited by EMA as clinically relevant in IPF patients and basis for ODD

BAL fluid and plasma correlation indicates GB0139 directly impacts lung function PDGF-BB PAI-1 Galectin-3 CCL18 YKL-40

Comparison: GB0139 MoA to alternative programs 13

GB0139: Phase 2b IPF Study In Progress Randomized, placebo controlled 52 week study

450 IPF patients in 3 arms

First-patient, first-visit in Q1 2019

Expected completion in mid 2022

Primary outcome measure:

Annualised rate of FVC decline over 52 weeks

Study is also powered to see an effect in the patients on neither pirfenidone nor nintedanib

Key secondary outcomes:

Safety, DLCO , 6 minute walk test, Quality of Life

14 * DLCO - Diffusing Capacity for Carbon Monoxide (*)

Ground-breaking novel treatment of IPF, an orphan disease with poorly tolerated treatments

Inhaled, delivered directly to the site of active lung destruction

Well tolerated in trials to date

Reaches the target cell in the lung at high concentrations

Causes a dose-related reduction in cell surface galectin-3 deep within patient lungs

Promising biomarker trends observed in Phase 2a study - validated by EMA as clinically relevant in IPF patients and basis for ODD

Phase 2b study underway - FDA and Medicines and Healthcare Products Regulatory Agency (MHRA) approved design

Conditional approval possible after Phase 2b completion GB0139: Inhaled Galectin-3 Inhibitor Summary 15

GB2064: LOXL2 Inhibitor for Myelofibrosis and Other Fibrotic Diseases 16

GB2064: Oral LOXL2 Inhibitor in Myelofibrosis GB2064 (previously PAT-1251)

A small-molecule inhibiting LOXL2, an enzyme that catabolizes the formation of lysine cross-linking in fibrillar collagens

Potentially disease modifying

Opportunity in multiple fibrotic indications

Orphan indication: 16,000 - 18,500 patients in US

Current therapies (JAK inhibitors) are not disease modifying

Large market - Incyte's Jakafi achieved $1.7bn in 2019 sales

17 Overview and Treatment Opportunity LOX Family Gene Expression in Myelofibrosis Stromal Cells LOXL2 paralogue most upregulated in active myelofibrosis

GB2064: Demonstrated In Vitro Inhibition of LOXL2 GB2064 is a small-molecule inhibitor of the LOXL2 catalytic site, not an antibody approach

GB2064 therefore has the potential to avoid the in vivo target low tissue penetration and target engagement encountered by Gilead's simtuzumab

GB2064's superior efficacy to simtuzumab has been observed in cell-based assays and preclinical models 18 GB2064 fully inhibits LOXL2 activity using a variety of substrates GB2064 (Galecto)

Study to be led by Professor Srdan Verstovsek, MD Anderson

Single arm open label study, allowing real time read of safety and activity

Patients who are ineligible for JAK-inhibitors or who do not tolerate JAKi

bone marrow general histology and fibrosis

PK to show drug levels in target tissue

imaging for spleen and liver volume

MYLOX-1: GB2064 in Myelofibrosis 19

GB2064: Phase 2a in Myelofibrosis Summary Ample evidence for central role of LOXL2 in fibrosis

GB2064 potently inhibits LOXL2 and shows antifibrotic activity in numerous models

Upcoming Phase 2a could generate both target engagement and efficacy data in the same study as repeated biopsies are already standard practice

Opportunity for both orphan designation and fast track following data in this indication

IND approved October 2020, and Phase 2a to start in coming months

Phase 1 SAD/MAD study already completed

Chronic toxicology studies completed

Robust efficacy in lung, liver and kidney models

GB1211: Oral Galectin-3 Inhibitor for Cancer and Fibrosis 21

22 Galecto's Oral Galectin-3 Inhibitors Galectin-3 is a very attractive target for a series of currently poorly treated indications, including many cancer types and fibrosis

Galecto is pioneering galectin field and has developed a series of orally active, specific and potent inhibitors of galectin-3

These bind to the carbohydrate recognition domain and inhibit the galectin-3 related effects on several key cell types

The lead compound, GB1211, reduces fibrosis and cancer growth in several different animal models

Well tolerated in IND-enabling studies