ALXO Corporate Presentation

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Certain information set forth in this presentation contains “forward-looking information” , under applicable laws collectively referred to herein as forward-looking statements. Except for statements of historical fact, information contained herein constitutes forward-looking statements and includes, but is not limited to the (i) results and cost and timing of our product development activities and clinical trials; (ii) completion of the Company’s clinical trials that are currently underway, in development or otherwise under consideration; (iii) our expectations about the timing of achieving regulatory approval and the cost of our development programs; (iv) projected financial performance of the Company; (v) the expected development of the Company’s business, projects, collaborations and joint ventures; (vi) execution of the Company’s vision and growth strategy, including with respect to future M&A activity and global growth; (vii) sources and availability of third-party financing for the Company’s research and development; (viii) future liquidity, working capital, and capital requirements; and (ix) industry trends. These and other risks are described more fully in ALX Oncology’s filings with the Securities and Exchange Commission (“SEC”), including ALX Oncology’s Annual Report on Form 10-K and other documents ALX Oncology files with the SEC from time to time. Although forward-looking statements contained in this presentation are based upon what management of the Company believes are reasonable assumptions, there can be no assurance that forward-looking statements will prove to be accurate. Actual results and future events could differ materially from those anticipated in such statements. The Company undertakes no obligation to update forward-looking statements if circumstances or management’s estimates or opinions should change except as required by applicable securities laws. This presentation concerns product candidates that are under clinical investigation, and which have not yet been approved for marketing by the U.S. Food and Drug Administration. These product candidates are currently limited by federal law to investigational use, and no representation is made as to their safety or effectiveness for the purposes for which they are being investigated. This presentation also contains estimates and other statistical data made by independent parties and by ALX Oncology relating to market size and growth and other industry data. This data involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. In addition, projections, assumptions, and estimates of ALX Oncology’s future performance and the future performance of the markets in which it operates are necessarily subject to a high degree of uncertainty and risk. Forward-looking Statements ALX Oncology Corporate Presentation2

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ALX Oncology Corporate Presentation3 ALX is Rapidly Advancing Novel Cancer Treatments Evorpacept ALX2004 • Leading CD47 program in development with potential to be next targeted immuno- oncology breakthrough • Unique design with inactive Fc is differentiated from past attempts to target CD47 • Demonstrated activity in five combinations to date and a targetable CD47 biomarker • Focused development strategy on track with ongoing trials in breast cancer and multiple myeloma* • Highly differentiated EGFR ADC now in Ph1 dose escalation in the US • Meticulously designed and developed in- house to maximize therapeutic window • Preclinical data support dose dependent activity and a differentiated safety profile • Targeting EGFR-expressing tumors in Ph1 including NSCLC, CRC, HNSCC, and ESCC * Sanofi-sponsored trial

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4 ALX Is Focused on Driving Toward Two Key Inflection Points in 2026 P R O G R A M I N D I C A T I O N A N T I C I P A T E D M I L E S T O N E S E V O R P A C E P T ASPEN-Breast Evorpacept, trastuzumab + chemotherapy ENHERTU®-Experienced HER2-Positive Breast Cancer FPI Q4 2025 Interim data – Q3 2026 A L X 2 0 0 4 ALX2004 Dose-escalation and expansion EGFR-Expressing Solid Tumors First patient dosed August 2025 Initial safety data – 1H 2026 Projected Cash Runway into Q1 2027 Cash, cash equivalents, and investments of $67M as of Sept 30, 2025 ALX Oncology Corporate Presentation

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M O D A L I T Y / T A R G E T P R O G R A M I N D I C A T I O N I N D E N A B L I N G P H A S E 1 P H A S E 2 P H A S E 3 S T A T U S E V O R P A C E P T P R O G R A M S Anti-cancer Antibodies ASPEN-Breast Evorpacept, Trastuzumab + chemotherapy ENHERTU®-Experienced HER2-Positive Breast Cancer FPI Q4’25 SARCLISA® + Dexamethasone1 + Evorpacept RRMM (Relapsed or Refractory Multiple Myeloma) Dose escalation complete, now in dose optimization ASPEN-06 Evorpacept, Trastuzumab, CYRAMZA® + Paclitaxel2 2L or 3L Advanced HER2-Overexpressing Gastric/Gastroesophageal Junction (GEJ) Completed, established POC Zanidatamab3 + Evorpacept HER2-Expressing Breast Cancer and Other Cancers Completed, data presented at SABCS ‘24 A L X 2 0 0 4 P R O G R A M EGFR ADC ALX2004 Dose-escalation and expansion EGFR-Expressing Solid Tumors First patient dosed August ‘25 ALX Oncology Corporate Presentation5 ALX Oncology is Pursuing a Focused Development Plan ALX Oncology retains worldwide rights to evorpacept 1. Sanofi sponsors SARCLISA® clinical trial. 2. Lilly supplies CYRAMZA® for ALX Oncology’s ASPEN-06 program 3. Jazz Pharmaceuticals sponsors zanidatamab clinical trial. ALX-sponsored trial Completed trial

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EVORPACEPT Advancing A Synergistic Approach to Cancer Treatment

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ALX Oncology Corporate Presentation7 Evorpacept Blocks the CD47-SIRPα Interaction, Enhancing the Targeted ADCP of Cancer Cells when Given in Combination with Anti-Cancer Antibodies M A C R O P H A G E C A N C E R C E L L Evorpacept Target antigen Anti-cancer antibody SIRP⍺ Don’t Eat Me CD47 Eat Me FcγR M A C R O P H A G E Don’t Eat Me M A C R O P H A G E Cancer cells overexpress CD47 in order to evade immune detection ADCP of anti-cancer antibodies is inhibited by CD47 Evorpacept blocks the “don’t eat me” signal and maximizes anti-cancer activity C A N C E R C E L L C A N C E R C E L L SIRP⍺ SIRP⍺ CD47 CD47 Eat Me Target antigen Anti-cancer antibody FcγR

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ALX Oncology Corporate Presentation8 Evorpacept Is the Only CD47 Blocker with an Inactive Fc Designed to Avoid Toxicities Seen with Conventional Anti-CD47 Fcγ R Fcγ R Evorpacept with inactive Fc Inactive Fc spares normal cells minimizing toxicity SIRP⍺ CD47 Fcγ Conventional Anti-CD47 M A C R O P H A G E R e d B l o o d C e l lEat me Due to CD47’s expression on red blood cells, this caused on-target, off-tumor toxicities Conventional anti-CD47 with active Fc

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ALX Oncology Corporate Presentation9 Evorpacept Has Demonstrated Consistent Tolerability and Robust Clinical Activity vs. Conventional CD47 Approaches Clinical Validation in a Randomized Trial Yes No Hematologic Toxicity Signal Low High Dosing Schedule Flexibility High Low Targeted Impact on Tumors High Low CD47 Affinity High Low/Medium Therapeutic Window Broad Narrow Inactive Fc domain Active Fc domain

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ALX is Driving a Unique Approach to Targeting CD47 and Is Leading Into a New Era of CD47 Biomarker Driven Targeted Oncology 2009 2014 2016 2018 2020 2022 2024 Demonstration of CD47 blocker without active Fc1 ALX Oncology incorporated Evorpacept First patient dosed Evorpacept Further increased benefit in CD47-high GC Preclinical data for CD47 in AML2 Forty Seven Bio FPI magrolimab Gilead acquires Forty Seven (magrolimab) for $4.9B FDA full clinical hold on magrolimab MDS and AML trials Pfizer acquires Trillum; (maplirpacept) for $2.3B Evorpacept Positive clinical data from combination with antibodies in gastric (GC), NHL and breast cancers (BC) Development halted for many conventional CD47 blockers with active Fc Evorpacept Ongoing Studies in BC and MM Pfizer pauses ph2 maplirpacept trial in DLBCL Evorpacept ALX / Sanofi collaboration in Multiple Myeloma (MM) with Sarclisa CD47 blocker w/ Inactive Fc (combination agent) The Competition Evorpacept Ongoing Ph1b antibody combinations tested 1. Garcia et al demonstrate decoupled CD47 blockade enhances ADCP of trastuzumab, cetuximab, rituximab 2. Weissman, et al, demonstrate preclinical data for drugging CD47 in AML 2025 ALX Approach Conventional CD47 blocker with active Fc (single agent) ALX Oncology Corporate Presentation10

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EVORPACEPT Clinical data with anti-cancer antibodies

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ALX Oncology Corporate Presentation12 Evorpacept Demonstrated a Manageable Safety Profile in ASPEN-06 and Consistently Across Trials • The incidence of adverse events due to any cause was comparable by arm • There were 12 patients with Grade 5 treatment emergent adverse events (5 for ETRP; 7 for TRP), only three of which were deemed to be treatment related: esophageal perforation and acute respiratory failure (ETRP), and pneumopathy (TRP). Neither event in ETRP was attributable to evorpacept. All causality adverse events, by grade Grade 5 Grade 4 Grade 3 Grade 2 Grade 1 All G5 TEAEs: ETRP (N=5): sepsis N=2, esophageal perforation N=1, respiratory failure N=1, acute respiratory failure N=1. TRP (N=7): sepsis N=1, pneumonia/pneumopathy/respiratory infection N=1 each, sudden death N=1, death from unknown cause N=1, esophageal hemorrhage N=1; data cutoff as of 15May 2025 Two G5 TEAEs due to disease progression were not included for ETRP Evo Evorpacept TrastuzumabT RamucirumabR PaclitaxelP N=63 ControlEvo T R P+ + + N=63 T R P+ + 100% 80% 60% 40% 20% 0 20% 40% 60% 80% 100% Evorpacept has been studied in >750 patients treated to date, with the overall safety profile being characterized by generally manageable and reversible adverse events

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ALX Oncology Corporate Presentation13 Evidence that Evorpacept Improves Upon Anti-Tumor Activity of Standard of Care Anti-Cancer Antibodies in Solid and Hematologic Tumors 26% 65% Gastric (CD47-high expression and retained HER2+1) ORR N = 23 N = 20 22% 56% Breast (R/R HER2+ by central assessment 2) ORR N = 9 18% 54% 34% 83% NHL (R/R Indolent) CR Rate N = 11 N = 18 Trastuzumab + ramucirumab + paclitaxel Evo + trastuzumab + ramucirumab + paclitaxel Margenza® + Chemo Benchmark3 Evo + Zanidatamab2 Rituximab Benchmark6 Evo + Rituximab4 R-squared Benchmark6 Evo + R-squared5 1. Above results are based on May 15, 2025 pre-planned exploratory analysis of ASPEN-06 gastric study. Retained HER2+ based on fresh biopsy or ctDNA amplification; CD47-high is ≥ 10% cells IHC3+; 2. SABCS 2024 #PS8-09; HER2+ by central assessment; 3. Margenza prescribing information; 4. ASPEN-01, Kim, Haematologica, 2025; 5. AACR 2024 #10285; 6. AUGMENT study, Leonard, JCO, 2019 ORR = overall response rate; CR = complete response; IST = investigator-sponsored trial ASPEN-06 subset, randomized Ph2 ASPEN-01 Ph1b and historic benchmark IST and historic benchmark Phase 1b/2 subset - Collaboration4 and historic benchmark

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ALX Oncology Corporate Presentation14 ASPEN-06 Phase 2: Evorpacept Plus Trastuzumab + Ramucirumab + Paclitaxel (TRP) in HER2+ Advanced/Metastatic GC/GEJ Adenocarcinoma Evorpacept T R P+ + + 1:1 VS. Control GC- gastric cancer, GEJ- gastroesophageal junction, TRP- trastuzumab, ramucirumab, paclitaxel. Retained HER2+: (1) Fresh HER2-positive is defined as biopsies that were HER2-positive after receiving prior HER2-targeted treatment, and (2) HER2 (ERBB2) plasma gene amplification from Guardant360® analysis; (3) 6 patients with confirmed HER2+ had missing CD47 samples or non-evaluable samples Evo Evorpacept (30 mg/kg Q2W) Trastuzumab (6 mg/kg > 4 mg/kg Q2W)T Ramucirumab (8 mg/kg Q2W)R Paclitaxel (80 mg/m2 on day 1, 8, 15 of 28-day cycle)P Key eligibility criteria • HER2+ GC or GEJ that has progressed on or after prior HER2- directed therapy (e.g. trastuzumab) • 2L or 3L • Prior trastuzumab deruxtecan (ENHERTU) and/or checkpoint inhibitors allowed • Prior CD47-agent, anti-SIRPα, or ramucirumab excluded • Patients enrolled with either a HER2+ fresh or archival biopsy Patients enrolled with either a HER2+ fresh or archival biopsy N=127 Retained HER2+ n=95 CD47 IHC assessment3 HER2+ on a fresh biopsy1 or by ctDNA2 CD47 high (≥10% IHC3+) n=43 CD47 low (<10% IHC3+) n=47 ITT 43 patients had retained HER2+ and were CD47-high ASPEN-06 Trial Design Study Flow Diagram T R P+ +

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15 CD47 Expression Acts as a Predictive Biomarker for Durable Patient Benefit from Evorpacept in the ASPEN-06 Trial 65.0 26.1 37.5 26.1 0 10 20 30 40 50 60 70 80 90 100 ORR in retained HER2+ (n=95) CD47-High (IHC3+ ≥10%) All Retained HER2+ CD47-Low (IHC3+ <10%) n=48 Evorpacept + TRP TRP 48.9 25.0 0 10 20 30 40 50 60 70 80 90 100Confirmed ORR, % n=20 By CD47 expression n=47 n=48 n=20 n=23n=23 n=24 ALX Oncology Corporate Presentation ORR by CD47 expression level in retained HER2+ Wainberg et al., The 2025 Society for Immunotherapy of Cancer (SITC) Annual Meeting, November 5–9, 2025. Abstract #496. Note: Above results are based on pre-planned exploratory analysis of ASPEN-06 gastric study. Retained HER2+ based on fresh biopsy or ctDNA amplification. Data Cutoff as of May 15, 2025. T = trastuzumab; R = ramucirumab; P = paclitaxel.

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Median DOR in Patients with CD47-High Expression was Longer for Evorpacept + TRP vs TRP Wainberg et al., The 2025 Society for Immunotherapy of Cancer (SITC) Annual Meeting, November 5–9, 2025. Abstract #496. Note: Above results are based on pre-planned exploratory analysis of ASPEN-06 gastric study. Retained HER2+ based on fresh biopsy or ctDNA amplification. Data Cutoff as of May 15, 2025. T = trastuzumab; R = ramucirumab; P = paclitaxel. 16 ALX Oncology Corporate Presentation 0 5 10 15 20 25 30 Median Duration of Response Months 25.5 11.2 9.1 8.4 12.0 15.7 Evorpacept + TRP TRPAll Retained HER2+ CD47-High (IHC3+ ≥10%) CD47-Low (IHC3+ <10%) By CD47 Expression

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The Addition of Evorpacept Reduced Risk of Disease Progression or Death by 61% for Patients with Retained HER2+ Disease and High CD47 Expression Hazard Ratio = 0.39 (95% CI: 0.17, 0.86) Median PFS (95% CI) Evo + TRP 18.4 mos (5.6, 31.0) TRP 7.0 mos (2.9, 9.0) Median Follow-Up: 19.4 months A. Progression-Free Survival Patients with CD47-High Expression and Retained HER2+ Evorpacept + TRPTRP Progression-Free Survival Events / N: 12/20 (60%) Events / N: 18/23 (78.3%) 17 ALX Oncology Corporate Presentation Wainberg et al., The 2025 Society for Immunotherapy of Cancer (SITC) Annual Meeting, November 5–9, 2025. Abstract #496. Note: Above results are based on pre-planned exploratory analysis of ASPEN-06 gastric study. Retained HER2+ based on fresh biopsy or ctDNA amplification; Data Cutoff as of May 15, 2025. T = trastuzumab; R = ramucirumab; P = paclitaxel. Evorpacept + TRP TRP

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The Addition of Evorpacept Led to Improved Overall Survival for Patients with Retained HER2+ and High CD47 Expression Patients with CD47-High Expression and Retained HER2+ Evorpacept + TRPTRP Overall Survival Events / N: 14/20 (70.0%) Events / N: 18/23 (78.3%) 18 ALX Oncology Corporate Presentation Wainberg et al., The 2025 Society for Immunotherapy of Cancer (SITC) Annual Meeting, November 5–9, 2025. Abstract #496. Note: Above results are based on pre-planned exploratory analysis of ASPEN-06 gastric study. Retained HER2+ based on fresh biopsy or ctDNA amplification; Data Cutoff as of May 15, 2025. T = trastuzumab; R = ramucirumab; P = paclitaxel. Hazard Ratio = 0.63 (95% CI: 0.30, 1.31) Median OS (95% CI) Evo + TRP 17.0 mos (8.5, NE) TRP 9.9 mos (7.2, 18.3) Median Follow-Up: 25.1 months Evorpacept + TRP TRP

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ALX Oncology Corporate Presentation19 Evorpacept + TRP Showed Consistent Benefit Across Multiple CD47 Cut-Points in Retained HER2+ and CD47+ Patients in the ASPEN-06 Study aCD47 cut-off defined by cell staining intensity: Medium = IHC2+; High = IHC3+. bThe HR is estimated from a Cox proportional hazards model with the treatment, region=Asia (Yes/No) and the use of prior T-DXd (Yes/No) as covariates CD47 Cut-offa % of HER2+ Subgroup (n=95) ORR PFS HRb (95% CI) OS HRb (95% CI)Evorpacept + TRP TRP No cut-off 100% 49% (n=47) 25% (n=48) 0.72 (0.44, 1.18) 0.95 (0.58, 1.56) ≥10% Med/High 57% 56% (n=25) 24% (n=29) 0.40 (0.19, 0.82) 0.75 (0.39, 1.46) ≥25% Med/High 40% 60% (n=20) 22% (n=18) 0.36 (0.15, 0.84) 0.65 (0.30, 1.41) ≥5% High 51% 64% (n=22) 23% (n=26) 0.38 (0.17, 0.84) 0.66 (0.32, 1.37) ≥10% High 45% 65% (n=20) 26% (n=23) 0.39 (0.17, 0.86) 0.63 (0.30, 1.31) Wainberg et al., The 2025 Society for Immunotherapy of Cancer (SITC) Annual Meeting, November 5–9, 2025. Abstract #496. Note: Above results are based on pre-planned exploratory analysis of ASPEN-06 gastric study. Retained HER2+ based on fresh biopsy or ctDNA amplification; Data Cutoff as of May 15, 2025. T = trastuzumab; R = ramucirumab; P = paclitaxel.

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EVORPACEPT Breast Cancer

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This study provides clinical data supporting further development of evorpacept with HER2-targeted agents in patients with breast cancer 21 Phase 1b/2 Trial Evaluating Safety and Efficacy of Evorpacept Plus Zanidatamab in Patients Who Have Progressed on Prior HER2-Directed Therapy Key eligibility criteria: Cohort 1 • HER2-positive breast cancer (IHC 3+ or IHC 2+/FISH-positive) • ≥3 prior regimens, must include trastuzumab, pertuzumab and either T-DM1, tucatinib, or T-DXd • Data were analyzed for all patients enrolled and based on central assessment Treatment1 1. Mandatory IRR prophylactic treatment included corticosteroids, antihistamines, and acetaminophen. Study conducted by Jazz Pharmaceuticals; Median follow-up (range) was 9.6 (0.6, 29.7) months, with six patients on treatment at data cutoff as of August 1, 2024; HER2-Low/Ultralow = IHC1+, IHC2+ / ISH-, IHC 0 Montero AJ et al., San Antonio Breast Cancer Symposium, December 2024, PS8-09 Evorpacept Zanidatamab+ 30 mg/kg Q2W 1200 mg (<70 kg) OR 1600 mg (≥ 70kg) Q2W ALX Oncology Corporate Presentation 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Confirmed ORR Confirmed ORR in patients treated with evorpacept + zanidatamab in Cohort 1 33% N=21 Cohort 1 All patients 56% N=9 Confirmed HER2+ by central assessment 17% N=12 HER2-low or ultralow by central assessment

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22 Strong expected benefit in CD47-high and HER2+ patients enables evorpacept-attributable benefit in single-arm study Key eligibility criteria ▪ HER2+ mBC (IHC3+ or IHC2+/ISH+) ▪ Measurable disease per RECIST 1.1 ▪ Prior trastuzumab deruxtecan (T-DXd) ▪ All approved treatments are allowed post T-DXd therapy ▪ ECOG 0-1 Evorpacept Trastuzumab+ Physician’s Choice Chemo1+ N=80 • Inclusion of both CD47-high and CD47-low patients enables evaluation of the value of CD47 as a biomarker for evorpacept and will inform the design of a registrational study #NCT07007559. 1) Capecitabine, eribulin, gemcitabine, paclitaxel, or vinorelbine ALX Oncology Corporate Presentation Interim data anticipated Q3 2026 Key objectives Primary ▪ ORR in HER2 ctDNA+ subpopulation Secondary ▪ ORR in HER2 ctDNA+ subpopulation by level of CD47 expression ▪ CBR, DOR, PFS, OS, and safety Exploratory ▪ ORR in HER2 ctDNA-negative subpopulation

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2L+ HER2+ 48K1 Confirmed HER2+ 60-80%2 CD47 High 50-70%3 HER2+ and CD47-High 2L+ BC Represents a Significant Initial Commercial Opportunity with Potential to Move into Earlier Lines of Therapy Annual market opportunity based on: 1) US, EU5, JPN addressable patients; ~18k patients in the US; (2) ALX advisory board feedback on breast cancer trial; (3) ALX analysis of Alhanafy, 2024; Sun, 2022; Kosaka, 2021; Chen, 2022; Yuan, 2019 and Tsao, 2025 ; (4) Monthly price estimate is based on benchmarks in US and extrapolated to core markets. ~20K addressable patients are CD47-high Represents $2-4B market opportunity in CD47- high, HER2+ 2L+ BC4 23 ALX Oncology Corporate Presentation

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ALX2004 EGFR ADC

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25 ALX2004 was Designed to Maximize the Therapeutic Window and Has the Potential to Establish Proof-of-Concept Early in Development Cycle EGFR antibody: Matuzumab-derived EGFR antibody selected to minimize off-tumor skin toxicity and to maximize therapeutic window Epitope distinct from that of FDA-approved EGFR antibodies Proprietary linker-payload: Lysosomal cleavage like deruxtecan ADCs with improved linker-antibody stability to minimize off- tumor payload release Proprietary top1i payload, DAR 8: Top1i with similar direct cytotoxic potency and enhanced bystander activity compared to deruxtecan ALX2004 EGFR-targeted ADC DAR 8 topoisomerase I Inhibitor payload (Top1i) ALX Oncology Corporate Presentation

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ALX Oncology Corporate Presentation26 Preclinical Data Support Dose Dependent Activity and Differentiated Safety Profile • Dose-dependent activity across a range of tumors, EGFR expression levels, and mutations • Potent anti-tumor activity in clinically relevant xenograft models • Demonstrated dose- dependent activity in patient-derived CRC model Safety profile in NHP toxicity studies support clinical development plans • Does not show EGFR-related skin toxicity at clinically relevant doses • No evidence of payload- related ILD in NHP toxicity studies, potentially due to linker stability A N T I-T U M O R A C T I V I T Y S A F E T Y NHP: Non-human primate; ILD: interstitial lung disease; CRC: colorectal cancer

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ALX Oncology Corporate Presentation27 Highly Differentiated Design for ALX2004 Optimizes Validated Payload and Antibody to Maximize the Potential for Success ALX2004 Design Approach • Select optimal linker and payload. Top1i most validated and tolerable payload • Use validated targets and drug designs • Maximize therapeutic window through binding epitope and affinity ALX2004 EGFR ADCs (monospecific) EGFR ADCs (bispecific) Payload tolerability Proprietary Top1i payload Mostly MMAE or eribulin (↑ toxic) Majority utilize Top1i payload Validated drug target Validated EGFR target Validated EGFR target Unvalidated secondary target / combination Optimized antibody Differentiated epitope and affinity Mostly cetuximab based Bispecific complexity

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ALX Oncology Corporate Presentation28 ALX2004 Linker-Payload Designed to Deliver Payloads to Tumors, Not the Periphery Less drug delivered to off-tumor, off- target tissues ▪ ALX2004 linker designed with improved stability in circulation to minimize off-tumor linker-payload release More drug delivered to the tumor ▪ ALX2004 linker-payload shows improved extracellular stability over industry-standard deruxtecan linker- payload Analysis of drug-to-antibody ratio over time in NHP model ALX’s proprietary linker-payload conjugated to trastuzumab shows improved stability compared to in-house generated trastuzumab-deruxtecan Wong et al., AACR-NCI-EORTC 2025. Abstract #A119

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ALX Oncology Corporate Presentation29 ALX Proprietary Linker-Payload Shows Superior Activity Compared to Deruxtecan ADCs in CDX Mouse Models Comparator is an in-house generated ADC comprising the ALX2004 antibody conjugated to the deruxtecan linker -payload ▪ ALX2004 performed as well or better vs. deruxtecan comparator in high-mid EGFR-expressing mouse models ▪ ALX2004 outperformed deruxtecan comparator in bystander effect model ▪ Improved bystander effect also demonstrated in cell-based bystander effect assay Percent of tumor-free mice in models with varying levels of EGFR expression (N=5 mice / bar) NCI-H292 (~80k/cell) mixed with SW620 (~2k/cell) in vivo High EGFR expressing CDX models MDA-MB468 (TNBC) ~ 441k / cell FaDu (HCC) ~ 111k /cell H292 (NSCLC) ~ 80k /cell in vivo Bystander Effect CDX Model % Tumor Free Mice Wong et al., AACR-NCI-EORTC 2025. Abstract #A119 % Tumor Free Mice ALX2004 ALX2004_mAb-deruxtecan

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ALX Oncology Corporate Presentation30 ALX2004 Shows Potent Anti-Tumor Activity Across Multiple Tumor Types, Varying Levels of EGFR Expression and Mutational Status NCI-H1975 (NSCLC) EGFR L858R/T790M mt, EGFR: 50,000/cell surface HCC827 (NSCLC) EGFRdel19 mt EGFR: 145,000/cell surface COLO205 (CRC) wt EGFR, BRAF V600E EGFR: 12,000 /cell surface HCT116 (CRC) wt EGFR, KRAS G12D EGFR: 20,000/cell surface CFPAC-1 (PDAC) wt EGFR, KRAS G12V EGFR: 62,000/cell surface FaDu (HNC) wt EGFR P53 R248L mutation EGFR: 111,000/cell surface MDA-MB-468 (TNBC) wt EGFR, P53 R273C EGFR: 441,000 EGFR /cell surface Wong et al., AACR-NCI-EORTC 2025. Abstract #A119 A549 (NSCLC) wt EGFR, KRAS G12S EGFR: 27,000 / cell surface NCI-H292 (NSCLC) wt EGFR EGFR: 80,000 / cell surface Vehicle control ALX2004, 10 mg/kg ALX2004, 3 mg/kg ALX2004, 1 mg/kg

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ALX Oncology Corporate Presentation31 Safety Profile Findings in NHP Toxicity Support Clinical Development Plans Design 6-week repeat dose (Q3W dosing) with 6-week recovery period at 5, 10 and 20 mg/kg Key Findings 10 mg/kg dose (n=10) NOAEL (No Observed Adverse Effect Level) 20 mg/kg dose (n=10) HNSTD (Highest Non Severely Toxic Dose) ▪ All findings are minimal to moderate and fully recoverable ▪ No dose limiting major target organ toxicity, including on- target toxicity (i.e. skin or other EGFR expressing cells) ▪ No evidence of ILD GLP NHP Toxicology Study Wong et al., AACR-NCI-EORTC 2025. Abstract #A119; NHP = non-human primate

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ALX Oncology Corporate Presentation32 Phase 1 Clinical Development Plan in EGFR-Expressing Tumors HNSCC: head and neck squamous cell carcinoma; CRC: colorectal cancer; NSCLC: non -small cell lung cancer; ESCC: esophageal squamous cell carcinoma; RDE: recommended dose for expansion First patient dosed August 2025 Initial safety data anticipated 1H 2026 Dose Level 4 n=3+ Dose Level 3 n=3+ Dose Level 2 2 mg/kg Q3W n=3+ Dose Level 1 1 mg/kg Q3W n=3 Dose Level 5 n=3+ Dose Escalation Dose Finding (Phase 1a) ALX2004 IV Q3W in NSCLC, HNSCC, CRC, and ESCC Dose Exploration (optional) Explore cohorts at different doses and schedules to identify the RDE(s) 1 or 2 tumor types selected from Dose Escalation at up to 2 different doses and/or schedules For each selected tumor, if 2 doses or schedules are selected, patients will be randomized to the 2 groups BOIN Dose Escalation Dose Expansion (Phase 1b) n = up to 80 Potential to expand into Phase 2 single-arm study to support accelerated approval RDE(s) ✓

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ALX Oncology Corporate Presentation33 Phase 1 Trial Rationally Designed Around Tumor Types with Established Sensitivity to EGFR Directed Therapies HNSCC CRC NSCLC ESCC High EGFR expression Sensitivity to Top1i Sensitivity to EGFR therapeutics Significant unmet need representing over 450k patient prevalence in the metastatic setting across these tumor types in the US1 HNSCC: head and neck squamous cell carcinoma; CRC: colorectal cancer; NSCLC: non -small cell lung cancer; ESCC: esophageal squamous cell carcinoma; (1) Prevalent patient population across all lines of metastatic treatment according to Clarivate Decision Resources Guides.

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ALX is Rapidly Advancing Two Novel Cancer Treatments with Multiple Near- Term Catalysts in 2026 35 ALX Oncology Corporate Presentation 3 ALX2004 is a highly differentiated ADC in development for EGFR-expressing solid tumors now enrolling in a phase 1 trial 2 The addition of Evorpacept led to a compelling benefit for patients with high CD47 expression and retained HER2+ gastric cancer with the potential to translate to HER2+ breast cancer when combining with Trastuzumab and chemo 1 ALX is focused on driving toward multiple inflection points in 2026 across both our programs – Evorpacept and ALX2004 4 Our projected cash runway extends into Q1 2027 driving key milestones: ALX2004 initial safety (1H’26), ASPEN-Breast data (Q3’26)

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