inhibrxpresentationoctob

Outcomes Focused Innovation Driven October 2021

2 This presentation contains forward-looking statements. In some cases, you can identify forward-looking statements by the words “will,” “expect,” “intend,” “plan,” “objective,” “believe,” “estimate,” “potential,” “continue” and “ongoing,” or the negative of these terms, or other comparable terminology intended to identify statements about the future. These statements are based on management’s current beliefs and expectations. These statements include but are not limited to statements regarding Inhibrx, Inc.’s (the “Company”) business strategy, the Company’s plans to develop and commercialize its product candidates, the safety and efficacy of the Company’s product candidates, the Company’s plans and expected timing with respect to clinical trials and regulatory filings and approvals, and the size and growth potential of the markets for the Company’s product candidates. These statements involve substantial known and unknown risks, uncertainties and other factors that may cause the Company’s actual results, levels of activity, performance or achievements to be materially different from the information expressed or implied by these forward- looking statements. Additional information regarding the Company’s risks and uncertainties are described from time to time in the “Risk Factors” section of our Securities and Exchange Commission filings, including those described in our Annual Report on Form 10-K as well as our Quarterly Reports on Form 10-Q, and supplemented from time to time by our Current Reports on Form 8-K. The Company may not actually achieve the plans, intentions or expectations disclosed in its forward-looking statements, and you should not place undue reliance on the Company’s forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements the Company makes. The forward-looking statements 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, the Company has no current intention of doing so except to the extent required by applicable law. You should, therefore, not rely on these forward-looking statements as representing the Company’s views as of any date subsequent to the date of this presentation. The investigational product candidates discussed in this presentation have not been approved or licensed by the U.S. Food and Drug Administration or by any other regulatory authority, and they are not commercially available in any market. This presentation also contains estimates and other statistical data made by independent parties and by the Company relating to market size and growth and other data about its industry. 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 the Company’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. This presentation shall not constitute an offer to sell or the solicitation of an offer to buy securities. Presentation disclaimer

3 Inhibrx at a glance + Experienced leadership team + Proven innovation and execution VALIDATION FROM INDUSTRY LEADING PARTNERS All platforms and programs developed in-house with strong patent protection Inhibrx’s modular sdAb platform + Ability to precision engineer to specific target biology + Smaller than conventional antibodies + Antibody-like PK profile + Readily manufactured at high yields using standard processes

4 Four differentiated clinical programs INBRX-109 Tetravalent DR5 agonist + Single agent activity in chondrosarcoma and mesothelioma + Potential rapid path to approval in chondrosarcoma, registration study initiated + First combination cohorts: mesothelioma, pancreatic adenocarcinoma and Ewing sarcoma with data in H1 2022 INBRX-106 Hexavalent OX40 agonist + Potential across numerous tumors, including cold tumors + Strong mechanistic rational for PD-1 combination + Key data readouts in combination expansion cohorts in 2H 2022 INBRX-105 PD-L1 x 4-1BB tetravalent conditional agonist + Potential across all PD-L1 expressing tumors + 4-1BB agonism is clinically validated + Strong mechanistic rational for PD-1 combination + Key data readouts in combination expansion cohorts in 2H 2022 INBRX-101 AAT-Fc fusion protein + Potential for first meaningful advancement for patients in 35 years + Estimated ~$2B+ market size + Interim results show favorable safety and tolerability profile and potential to achieve normal AAT levels with monthly dosing + Registration study could start in late 2022 Oncology Cell death pathway Immuno-oncology Rare diseases

5 Why invest in Inhibrx? Backed by solid institutional investor base with substantial internal ownership Four differentiated clinical programs with value-creating readouts in 2H 2021/2022 KEY FINANCIAL HIGHLIGHTS* 37.8M $125.7M 42.1MRobust emerging pre-clinical pipeline Potential to reach financial sustainability with minimal dilution $20-25M per Qtr Cash Average burn rate Common stock outstanding Fully diluted outstanding *As of 6/30/2021 reported in last Form 10-Q

INBRX-101 Recombinant Alpha-1 Antitrypsin Fc-fusion Protein AAT Fc

7 Alpha-1 antitrypsin deficiency (AATD) Disease overview ⁺ AATD is an inherited orphan respiratory disease characterized by deficient levels of alpha-1 antitrypsin (AAT) causing loss of lung function and decreased life expectancy ⁺ A small percentage of patients also develop liver disease Current standard of care ⁺ Plasma-derived AAT (pdAAT) does not maintain patients in the normal AAT range, requires frequent once-weekly IV dosing, and requires plasma collection practices that might not be sustainable AAT Serum levels in patients receiving weekly pdAAT 60 M ea n Se ru m A AT le ve l ( μM ) 40 20 0 0 7 14 21 28 Day Normal AAT serum range (20 - 50 μM) Below normal AAT serum range (<20 μM) Dosing

8 Potential advantages of recombinant AAT Fc-fusion protein INBRX-101 Potential to extend the dosing interval from weekly to monthly Goal is to maintain patients in the normal serum range of AAT and to normalize the functional activity of AAT Recombinant manufacturing provides unlimited supply and less pathogen risk Potential advantages of INBRX-101

9 THERAPIES STATUS Plasma-Derived AAT Aralast Approved Glassia Prolastin-C Zemaira Inhaled AAT Phase 2 Oral Neutrophil Elastase Inhibitor Alvelestat Phase 2 Small Molecule Corrector ZF874 Phase 2 Competitive comparison Applicable to all patients THERAPIES STATUS ARO-AAT Phase 2 DCR-A1AT Phase 2 15% 100% Applicable to ~15% of patients with liver issues

10 INBRX-101 - Initial results from Phase 1, Part 1 N=24 Complete N= 6 10 mg/kg N= 6 40 mg/kg N= 6 120 mg/kg N= 6 80 mg/kg Single ascending dose escalation (SAD) PART 1 + Favorable safety and tolerability profile with no drug-related SAEs at doses up to and including 120 mg/kg SAD and 80 mg/kg MAD + Dose related increases in maximal and total exposure occurred across entirety of SAD range of 10-120 mg/kg + Revealed potential to achieve normal AAT levels with monthly dosing Key functional AAT levels by dose INBRX-101 single ascending dose (mg/kg) Fu nc tio na l A AT le ve ls (μ M ) 10 40 80 120 20 0 40 60 Baseline AAT Max AAT Day 21 AAT

11 Complete Initiated Remainder of Phase 1, Part 2 expected H1 2022 INBRX-101 - Initial results from Phase 1, Part 2 - 40 mg/kg N=18 * bronchoalveolar lavage N= 6 40 mg/kg N= 6 80 mg/kg* N= 6 120 mg/kg* INBRX-101 Initial Results - 40 mg/kg (Q3W) Initial data from 40 mg/kg predicts a dose of 80-120 mg/kg of INBRX-101 should meet the goal of maintaining normal serum AAT range (> 20 μM) and monthly dosing PART 2 Time (days) Fu nc tio na l A AT le ve ls (μ M ) 0 21 42 63 20 0 30 40 10 Multiple ascending dose escalation (MAD) *Indicates timing of each dose

INBRX-109 Tetravalent DR5 Agonist

13 Tetravalent DR5 agonist + Death receptor 5 (DR5) is a receptor for the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) + DR5 activation naturally eliminates damaged and neoplastic cells DR5: sdAb DR5: sdAbDR5: sdAb DR5: sdAb 105 kDa Fc: effector function disabled

14 INBRX-109 is a best-in-class DR5 agonist CANDIDATE VALENCY SIZE (KDA) STATUS INBRX-109 Tetravalent 105 Phase II TAS-266 Tetravalent 60 Discontinued1 Eftozanermin alpha (TRAIL-Fc fusion) Hexavalent 167 Phase I GEN10292 Dodecavalent 150 ka (2x mAbs) Phase I IGM-8444 Decavalent3 ~950 Phase I Dulanermin (recombinant TRAIL) Trivalent 150 Discontinued Tigatuzumab Bivalent 150 Discontinued LBY-135 Discontinued Conatumumab Discontinued Drozitumab Discontinued Lexatumumab Discontinued 1. Hepatoxicity – likely ADA hyper-crosslinking 2. Two hexamerizing non-competing mAbs 3. Size and rigidity of IgM may prevent effective clustering of DR5

15 Fast to market opportunity ~1,400 cases per year Incidence rate of ~1 in 200,000 persons per year USA Worldwide Chondrosarcoma *The figures on this slide represent market research estimates. No approved therapeutic for the treatment of chondrosarcoma Therapeutic IPI-926 (HH) Control arm Placebo Subject number 100 (2:1) Placebo arm PFS 2.9 months Therapeutic Regorafenib Control arm Placebo Subject number 46 (2:1) Placebo arm PFS 2 months PFS from placebo-controlled studies

16 Best Response 3mo 4mo 6mo 9mo 12mo SD (-20%) 62wks ► SD (-7%) 62wks PD SD (-11%) 54wks ► PR (-60%) PD SD (-13%) PD SD (+4%) ► PR (-32%) PD SD (-4%) ** SD (+5%) PD SD (+3%) * SD (-3%) * SD (-4%) * SD (+6%) PD SD (+7%) PD PD PD PD PD Weeks 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 45 46 47 48 49 50 51 52 53 54 55 INBRX-109 preliminary Phase 1 data in unresectable or metastatic conventional chondrosarcoma + Time on treatment in weeks + Data cut point 01-Jun-2021, data from Ph1 INBRX-109 study, study ongoing + Response per RECISTv1.1 per Investigator assessment, data subject to change (e.g., some data raw and not verified) PFS for placebo patients in comparative studies + PR=Partial Response, SD=Stable Disease, PD=Progressive Disease + ► Subject ongoing + *Off-study per subject request (e.g., resection) or **Investigator discretion

17 Endpoints Primary: Progression free survival Secondary: Overall survival, overall response rate, duration of response, disease control rate, quality of life INBRX-109 Phase 2 registration-enabling study design in chondrosarcoma Randomization Conventional chondrosarcoma, grade 2 and 3, unresectable or metastatic Stratification by line of therapy & Grade INBRX-109 Placebo Until PD or toxicity with cross-over *Including interim analysis N=134* N= 67 * 3 mg/kg every three weeks H2 2023 Initiated in Q2 2021

18 Best Response 3mo 4mo 6mo 9mo SD (-24%) * SD (-17%) SD (-12%) PR (-100%) SD (-22%) SD (-20%) sd (-12%) SD (-5%) SD (-2%) SD (+9%) SD (+13%) SD (+16%) SD (+1%) * PD PD PD PD (+25%) PD (+33%) PD (+33%) Weeks 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 Combination study Mesothelioma with Cis-/Carboplatin & Pemetrexed N=20 + Time on treatment in weeks + Data cut point 24-N0V-2020, data from Ph1 INBRX-109 study, study ongoing, single agent mesothelioma cohort closed + Response per RECISTvi.ior modified RECIST, and per Investigator assessment, data subject to change (e.g., some data raw and not verified) Preliminary Phase 1 data-malignant pleural mesothelioma, epithelioid subtype H1 2022 PART 3 + Efficacy population (subjects who completed 2 cycles and had at least one tumor assessment, or discontinued early due to PD); three subjects not evaluable for efficacy were excluded + PR=Partial Response, SD=Stable Disease, PD=Progressive Disease + * Off-study per subject or Investigator request

19 Initiated Ongoing FUTURE POTENTIAL OPPORTUNITIES Solid tumors + IAP antagonists Hematologic tumors + Bcl-2 inhibitors NSCLC + various combo agents Gastric and colon cancer + various combo agents Additional sarcoma indications INBRX-109 on the horizon Combination studies Pancreatic adenocarcinoma 2nd line with FOLFIRI N=20 Mid-2022 Ewing sarcoma with Irinotecan N=20 PART 3

INBRX-106 Hexavalent OX40 Agonist

21 Hexavalent OX40 agonist OX40 is a co-stimulatory receptor on activated T-cells: + Provides co-stimulation to activated T-cells + Reverses regulatory T-cell induced immune suppression + Enhances T-cell functionality + Additional benefit in combination with PD-1 blockade T T T T T T T T T OX40: sdAb OX40: sdAb OX40: sdAbOX40: sdAb OX40: sdAb OX40: sdAb Fc 129 kDa

22 INBRX-106 is a best-in-class OX40 agonist CANDIDATES VALENCY ISOTYPE LIGAND BLOCKING STATUS INBRX-106 Hex- IgG1 N Ph 1 (2019) MOXR-0916 Bi- IgG1 Y Discontinued GSK-3174998 Ph 1 (MM, 2019) BMS-986178 Ph 1 (2016) INCAGN-1949 Ph 1 (2016) ABBV-368 Ph 1 (HNSCC, 2020) IBI-101 Ph 1 (2018) MEDI-0562 Discontinued PF-04518600 Bi- IgG2 Y Discontinued BGB-A445 Bi- IgG1 N Ph 1 (2020)

23 INBRX-106 Phase 1 trial design No pre-screening, all-comers Dose optimization study OngoingOngoingCompleteSingle agent dose escalation Dose escalation with Keytruda™ Single agent dose expansion N=80N= 24 N= 13N=20 N=20 PD-L1+NSCLC N=20 Melanoma N=20 PD-L1+Basket N=20 PD-L1+NSCLC, CPI naїve PART 1 PART 2 PART 3 PART 4 + Well-tolerated with mild or moderate immune-related toxicities + Patients were not pre-screened for PD-L1 positivity + Longest duration as of June 1, 2021= 63 weeks + Greatest reduction in tumor volume= 23%(by RECIST v1.1) + Maximum administered dose was 3 mg/kg and no MTD reached H2 2021 H2 2022 Dose expansion with Keytruda™ Planned

INBRX-105 PD-L1 x 4-1BB Multispecific

25 PD-L1 x 4-1BB multispecific + Designed to provide spatially-restricted 4-1BB agonism at sites of PD-L1 expression + Highly expressed on tumor infiltrating immune cells, 4-1BB signaling promotes prolonged T-cell survival memory formation + Constitutive 4-1BB agonism has achieved anti-tumor responses, but was limited by immune-related toxicities PD-L1: sdAb 4-1BB: sdAb Fc Effector Disabled PD-L1: sdAb 4-1BB: sdAb 105 kDa

26 INBRX-105 is a best-in-class 4-1BB agonist CANDIDATE FORMAT 4-1BBL BLOCKING STATUS INBRX-105 Bivalent/Bivalent No Phase I Gen-1064 Monovalent/Monovalent n/a Phase II MCLA-145 Monovalent/Monovalent Yes Phase I FS222 Bivalent/Bivalent n/a Phase I PRS-343 Bivalent/Bivalent No Phase I ND021 Monovalent/Monovalent n/a Phase I CANDIDATE IGG SUBCLASS 4-1BBL BLOCKING STATUS Urelumab IgG4 Yes Discontinued Utomilumab IgG2 No Discontinued CTX-471 IgG4 No Phase I ADG106 IgG4 Yes Phase I ATOR-1017 IgG4 Yes Phase I AGEN2373 IgG1 No Phase I LVGN6051 unknown n/a Phase I PD-L1 x 4-1BB Bispecifics Monoclonal 4-1BB Antibodies

27 PlannedInitiatedOngoingComplete INBRX-105 Phase 1 trial design Single agent: PD-L1+ Basket Single agent dose escalation Single agent dose expansion N=80N= 32 N= 12N=32 No pre-screening, all-comers + 8/18 (44%) at dose levels ≥ 0.1 mg/kg achieved stable disease + Patients were not pre-screened for PD-L1 positivity + Longest duration= 41 weeks + Greatest reduction in tumor volume = 20% (by RECIST v1.1) + MTD= 1 mg/kg N=20 PD-L1+NSCLC N=20 Melanoma N=20 PD-L1+Basket N=20 PD-L1+NSCLC, CPI naїve N=8 PD-L1+NSCLC N=8 PD-L1+Melanoma N=8 PD-L1+NSCLC N=8 PD-L1+Basket H2 2021 H2 2022 PART 1 PART 2 PART 3 PART 4 Dose expansion with Keytruda™ Dose escalation with Keytruda™

28 Near term expected clinical milestones Q4 2021 H1 2022 H2 2022 (OX40) / Keytruda dose escalation data (OX40) / Keytruda dose expansion cohort data(AAT) Additional Phase 1 data (PD-L1 x 41BB) Keytruda dose escalation data (DR5) Initial pancreatic and mesothelioma combination study data (PD-L1 x 41BB) Keytruda dose expansion cohort data (DR5) Ewing sarcoma combination study data INBRX-105 INBRX-109 INBRX-109 INBRX-105 INBRX-106 INBRX-101 INBRX-106 INBRX-101 (AAT) Potential start to registration study

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