Macrogenics, Inc. the Incyte Logo Is a Registered Trademark of Incyte Corporation

Developing Breakthrough Biologics, Life-changing Medicines

Corporate Update June 5, 2019 Legal Notices The information in this slide deck is current as of June 5, 2019, unless otherwise noted. The information in this slide deck is qualified in its entirety by reference to MacroGenics’ Annual, Quarterly and Current Reports filed with the SEC. MacroGenics undertakes no obligation to update any of the information herein. Cautionary Note on Forward-Looking Statements Any statements in these materials about future expectations, plans and prospects for MacroGenics (“Company”), including statements about the Company’s strategy, future operations, clinical development of the Company’s therapeutic candidates, milestone or opt-in payments from the Company’s collaborators, the Company’s anticipated milestones and future expectations and plans and prospects for the Company and other statements containing the words “subject to”, "believe", “anticipate”, “plan”, “expect”, “intend”, “estimate”, “project”, “may”, “will”, “should”, “would”, “could”, “can”, the negatives thereof, variations thereon and similar expressions, or by discussions of strategy constitute forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including: the uncertainties inherent in the initiation and enrollment of future clinical trials, expectations of expanding ongoing clinical trials, availability and timing of data from ongoing clinical trials, expectations for regulatory approvals, other matters that could affect the availability or commercial potential of the Company's product candidates and other risks described in the Company’s filings with the Securities and Exchange Commission. In addition, the forward- looking statements included in this presentation represent the Company's views only as of the date hereof. The Company anticipates that subsequent events and developments will cause the Company's views to change. However, while the Company may elect to update these forward- looking statements at some point in the future, the Company specifically disclaims any obligation to do so, except as may be required by law. These forward-looking statements should not be relied upon as representing the Company’s views as of any date subsequent to the date hereof. Trademarks DART, TRIDENT, MacroGenics, the MacroGenics logo and “Breakthrough Biologics, Life-Changing Medicines” are trademarks or registered trademarks of MacroGenics, Inc. The Incyte logo is a registered trademark of Incyte Corporation. The Merck logo is a trademark of Merck Sharp & Dohme Corp. Investigational Agents All Company product candidates described or mentioned herein are investigational and have not yet been approved for marketing by any regulatory authority.

2 June 5, 2019 Committed to Developing Life-changing Medicines

Innovative Combinatorial Approaches Resourced for Success

Nine immuno-oncology clinical candidates $320M Cash @ 03/31/19(a)

Multiple alliances with Fc optimization platform to enhance antibodies’ immune activation leading biopharma companies

Commercial scale GMP Leading bispecific DART® platform to exploit multiple mechanisms manufacturing facility

~366 Employees Multi-program “franchises” around high-value targets (B7-H3, PD-1) (Rockville, MD & SF Bay Area)

(a) Includes cash equivalents and marketable securities.

3 June 5, 2019 Our Growing Immuno-Oncology Pipeline Retains major market commercial rights for 8 of 9 development candidates

Program (Target) Potential Indication Pre-IND Phase 1 Phase 2 Phase 3 Collaborator Our Commercial Rights

Margetuximab (HER2) Breast (HER2+) “SOPHIA” Zai Lab, Worldwide, excluding South Korea GC Pharma and Greater China Gastric (+anti-PD-1)

Enoblituzumab (B7-H3) Solid Tumors (+anti-PD-1) — Worldwide

MGD009 (B7-H3 × CD3) Solid Tumors — Worldwide

H3 -

B7 Solid Tumors (+MGA012)

MGC018 (B7-H3)(a) Solid Tumors — Worldwide

MGA012 (PD-1) Solid Tumors Incyte(b) — 1

- MGD013 (PD-1 × LAG-3) Solid Tumors/Heme Mal. Zai Lab Worldwide, excluding Greater China PD

MGD019 (PD-1 × CTLA-4) Solid Tumors — Worldwide

Flotetuzumab (CD123 × CD3) AML Servier North America, Japan, Korea, India

AML (+MGA012)

MGD007 (gpA33 × CD3) Colorectal (+MGA012) — Worldwide

“MGD” = DART “MGA” = Antibody “MGC” = ADC

(a) MGC018 is an antibody-drug conjugate (ADC) based on a duocarmycin payload with cleavable peptide linker that was licensed from Synthon Biopharmaceuticals. (b) MacroGenics retains rights to develop its pipeline assets in combination w/MGA012 (INCMGA0012) and to manufacture a portion of global clinical and commercial supply needs of MGA012. All Company product candidates described or mentioned herein are investigational and have not yet been approved for marketing by any regulatory authority.

4 June 5, 2019 Margetuximab Margetuximab: Novel Investigational Anti-HER2 mAb with Phase 3 Data at ASCO Engineered to enhance activation of immune system

• Inhibits HER2 signaling (similar to trastuzumab) Function/ MoA • Fc region optimized to enhance immune response, including ADCC

HER2 HER2

Fab Ongoing • HER2+ metastatic breast cancer (Ph. 3 SOPHIA) Region Studies • HER2+ gastric cancer (Ph. 2 combo study with PD-1)

• Positive Ph. 3 SOPHIA study PFS results; OS immature • BLA Submission expected in 2H19 Fc Region Status • Initiate Phase 2/3 MAHOGANY gastric study (w/checkpoint inhibitor) anticipated 2H19

MacroGenics’ Retained • Global rights (excl. Greater China, South Korea) Rights

5 June 5, 2019 Margetuximab Phase 3 Study Demonstrated Superiority to Trastuzumab in Primary Endpoint SOPHIA clinical trial met its first primary endpoint of improved progression-free survival (PFS)

Data presented at 2019 ASCO Annual Meeting Arm 1 margetuximab + HER2+ mBC Investigator’s Choice of chemotherapy 1–3 Prior Treatment Lines Chemotherapy in Metastatic Setting 1:1 Randomization (N = 536) (capecitabine, eribulin, R (including prior treatment with gemcitabine or vinorelbine) multiple other anti-HER2 agents)(a) Arm 2 trastuzumab + chemotherapy

• Sequential primary endpoints: PFS and OS − First interim analysis of OS at time of PFS analysis; second interim analysis planned at 270 events; final analysis planned at 385 events

• Patients carrying CD16A (FcγRIIIa) 158F allele were pre-specified Global sites: ~200 exploratory subpopulation PFS (N=257, HR=0.67, α=0.05, power=90%) OS (N=385, HR=0.75, α=0.05, power=80%)

(a) All study patients had previously received trastuzumab and pertuzumab, and approximately 90% had previously received ado-trastuzumab emtansine.

6 June 5, 2019 Margetuximab PFS Analysis in ITT Population PFS analysis was triggered by last randomization on October 10, 2018, after 265 PFS events occurred

24% Risk Reduction of Disease Progression 30% Risk Reduction of Disease Progression Central Blinded Analysis (Primary Endpoint) Investigator Assessed (Secondary Endpoint)

Margetuximab Trastuzumab Margetuximab Trastuzumab + Chemotherapy + Chemotherapy + Chemotherapy + Chemotherapy (n=266) (n=270) (n=266) (n=270) # of events 130 135 # of events 160 177 Median PFS 5.8 months 4.9 months Median PFS 5.6 months 4.2 months (95% CI) (5.52–6.97) (4.17–5.59) (95% CI) (5.06–6.67) (3.98–5.39) HR by stratified Cox model, 0.76 HR by stratified Cox model, 0.70 (95% CI, 0.59–0.98) (95% CI, 0.56–0.87) Stratified log-rank P=0.033 Stratified log-rank P=0.001

ITT population: N=536. CI=confidence interval. (Presented ASCO 2019)

7 June 5, 2019 Margetuximab PFS Subgroup Analyses

Median PFS (95% CI), Months HR by Unstratified Margetuximab + Trastuzumab + Unstratified 95% CI Log-Rank Chemotherapy Chemotherapy Cox Model P Value All patients, n=536 5.8 (5.52–6.97) 4.9 (4.17–5.59) 0.78 (0.61–0.99) 0.044 Capecitabine, n=143 8.3 (5.55–11.50) 5.5 (4.17–8.28) 0.77 (0.47–1.26) 0.302 Eribulin, n=136 6.0 (3.81–8.05) 4.2 (3.38–5.55) 0.66 (0.42–1.05) 0.080 Gemcitabine, n=66 5.4 (4.07–11.01) 3.5 (1.45–7.16) 0.58 (0.29–1.18) 0.128 Vinorelbine, n=191 5.6 (4.24–6.97) 5.1 (3.42–6.67) 0.90 (0.60–1.35) 0.606 >2 metastatic sites, n=254 6.3 (5.42, 8.08) 4.2 (3.38, 5.55) 0.63 (0.44–0.89) 0.009 ≤2 metastatic sites, n=282 5.7 (4.47, 6.97) 5.5 (4.24, 5.85) 0.94 (0.67–1.31) 0.702 Hormone Receptor-, n=200 5.8 (4.80, 7.23) 4.2 (2.83, 5.55) 0.58 (0.39–0.86) 0.007 Hormone Receptor+, n=334 5.7 (5.52, 8.18) 5.5 (4.24, 7.03) 0.88 (0.64–1.19) 0.393 HER2 IHC 3+, n=291 6.9 (5.55, 8.31) 5.6 (3.98, 5.85) 0.64 (0.46–0.90) 0.011 HER2 ISH amplified, n=245 5.5 (4.01, 6.60) 4.6 (4.07, 5.55) 1.01 (0.71–1.42) 0.972 Age >60 years, n=170 6.9 (5.52, 10.51) 5.6 (4.14, 5.85) 0.58 (0.36–0.92) 0.020 Age ≤60 years, n=366 5.6 (4.24, 6.97) 4.6 (4.01, 5.59) 0.87 (0.66–1.16) 0.337 Prior (neo)adjuvant Tx: yes, n=303 6.3 (5.55–8.05) 5.4 (4.01–5.59) 0.67 (0.48–0.93) 0.014 Prior (neo)adjuvant Tx: no, n=233 5.6 (3.71–6.97) 4.9 (4.07–7.16) 0.99 (0.68–1.42) 0.935 0.0 0.5 1.0 1.5 2.0 Margetuximab Better Trastuzumab Better

Hormone receptor positive=ER+ and/or PgR+; hormone receptor negative=ER- and PgR-; IHC=immunohistochemistry; ISH=in situ hybridization; Tx=treatment. (Presented ASCO 2019)

8 June 5, 2019 Margetuximab Planned* Exploratory PFS Analyses by FcR Genotype (by CBA) Margetuximab benefit appears to be increased in low-affinity CD16A-158F allele carriers

*Non-alpha allocating, exploratory analysis. † CD32B/TT not included on forest plot because n=9 is too small (5 on margetuximab, 4 on trastuzumab) to make analysis meaningful. (Presented ASCO 2019)

9 June 5, 2019 Margetuximab Planned Exploratory PFS Analysis by CD16A Genotype (by CBA) 506 patients genotyped (94%)

FF or FV, n=437 of 506 (86%) VV, n=69 of 506 (14%)

Margetuximab + Trastuzumab + Margetuximab + Trastuzumab + Chemotherapy Chemotherapy Chemotherapy Chemotherapy (n=221) (n=216) (n=37) (n=32) # of events 103 112 # of events 21 13 Median PFS 6.9 months 5.1 months Median PFS 4.8 months 5.6 months (95% CI) (5.55–8.15) (4.14–5.59) (95% CI) (2.46–5.65) (2.86–11.04) HR by unstratified Cox model, 0.68 HR by unstratified Cox model, 1.78 (95% CI, 0.52–0.90) (95% CI, 0.87–3.62) Unstratified log-rank P=0.005 Unstratified log-rank P=0.110

(Presented ASCO 2019)

10 June 5, 2019 Margetuximab October 2018 Interim OS* for ITT vs CD16A-158F Carriers 158 (41%) of 385 events needed for final OS analysis

ITT population, n=536 CD16A/FF or FV, n=437 of 506 (86%) Margetuximab + Trastuzumab + Margetuximab + Trastuzumab + Chemotherapy Chemotherapy Chemotherapy Chemotherapy (n=266) (n=270) (n=221) (n=216) # of events 78 80 # of events 59 65 Median OS 18.9 months 17.2 months Median OS 23.6 months 16.9 months (95% CI) (16.16–25.07) (15.80–33.31) (95% CI) (16.56–NA) (15.41–20.53) HR by stratified Cox model, 0.95 HR by unstratified Cox model, (95% CI, 0.69–1.31) 0.82 (95% CI, 0.58–1.17)

*First interim overall OS analysis at time of PFS analysis (Oct 10, 2018) was immature with 41% of 385 deaths needed for final OS analysis; stopping boundary was not crossed. Second interim OS analysis will occur after 270 deaths. Final OS analysis will occur after 385 deaths. NA=not achieved. (Presented ASCO 2019)

11 June 5, 2019 Margetuximab Overall Response and Clinical Benefit Rates Complement PFS

Margetuximab + Trastuzumab + P Value Chemotherapy (n=262) Chemotherapy (n=262)

Objective Response Rate 58 (22.1%) [17.3–27.7] 42 (16.0%) [11.8–21.0] 0.060* (CR+PR), n (%) [95% CI]

Clinical Benefit Rate 96 (36.6%) [30.8–42.8] 65 (24.8%) [19.7–30.5] 0.003* (CR+PR+SD>6 months), n (%) [95% CI] Best Overall Response, n (%) Complete Response 7 (2.7%) 4 (1.5%) Partial Response 51 (19.5%) 38 (14.5%) Stable Disease 149 (56.9%) 147 (56.1%) Progressive Disease 35 (13.4%) 46 (17.6%) Not Evaluable/Not Available 20 (7.6%) 27 (10.3%) Duration of Response 6.1 (4.11–9.13) 6.0 (4.01–6.93) 0.541† (CR, PR), median months (95% CI)

Response evaluable population (randomized patients with baseline measurable disease): N=524. *Stratified Mantel-Haenszel test P value (2-sided). †Unstratified log-rank P value (2-sided). (Presented ASCO 2019)

12 June 5, 2019 Margetuximab Summary of Adverse Events (AEs) Similar overall safety profiles

Margetuximab + Trastuzumab + Chemotherapy (n=264) Chemotherapy (n=265) Any grade AE, n (%) 258 (97.7) 255 (96.2) Grade ≥3 AE, n (%) 138 (52.3) 128 (48.3) SAE, n (%) 39 (14.8) 46 (17.4) AE leading to treatment discontinuation, n (%) 8 (3.0) 7 (2.6) AEs resulting in death,* n (%) 2 (0.8)† 2 (0.8)‡

Safety Population (randomized patients who received any study treatment): N=529. *No AEs resulting in death were considered related to anti-HER2 study therapy. †Pneumonia (n=1), pneumonia aspiration (n=1). ‡Pneumonia (n=1), acute kidney injury (n=1). SAE=serious AE. (Presented ASCO 2019)

13 June 5, 2019 Margetuximab AEs Regardless of Causality

Margetuximab + Trastuzumab + Chemotherapy (n=264) Chemotherapy (n=265) Most common AEs, n (%) All Grade* Grade ≥3† All Grade* Grade ≥3† Fatigue 103 (39.0) 12 (4.5) 92 (34.7) 7 (2.6) Nausea 81 (30.7) 3 (1.1) 84 (31.7) 1 (0.4) Neutropenia 73 (27.7) 51 (19.3) 51 (19.2) 30 (11.3) Diarrhea 59 (22.3) 6 (2.3) 62 (23.4) 5 (1.9) Anemia 48 (18.2) 12 (4.5) 55 (20.8) 17 (6.4) Neutrophil count decreased 32 (12.1) 22 (8.3) 35 (13.2) 25 (9.4) Febrile neutropenia 8 (3.0) 8 (3.0) 12 (4.5) 12 (4.5) AEs of special interest, n (%) All Grade Grade ≥3 All Grade Grade ≥3 Infusion-related reaction (IRR)‡ 34 (12.9) 4 (1.5) 10 (3.8) 0 Left ventricular dysfunction 6 (2.3) 3 (1.1) 7 (2.6) 1 (0.4) Discontinuation due to IRRs, n (%) 3 (1.1) 2 (0.8) 0 0

Safety Population: N=529. *Incidence ≥20% in either treatment group. †Incidence ≥5% in either treatment group. ‡All patients received prior trastuzumab. In pivotal trials of trastuzumab, IRRs occurred in 21% to 40% of patients (US package insert). (Presented ASCO 2019)

14 June 5, 2019 Margetuximab Capturing Full Potential of Margetuximab Planned development strategy

3 Future Opportunities • Neoadjuvant breast cancer • Other HER2+ populations

2 Follow-on Indications • 1st Line Gastric Cancer (w/checkpoints) − IND active, CFDA engaged − Phase 2/3 MAHOGANY initiation in 2H19 1 Potential Approval • BLA submission planned in 2H19 • 3rd/4th Line mBC (w/chemo)

15 June 5, 2019 Margetuximab Fully Enrolled Phase 2 Study in Advanced Metastatic Gastric Cancer Data from gastric cancer (HER2 3+) cohort disclosed at ASCO GI 2019

Dose Escalation Dose Expansion #1 Dose Expansion #2 (n=3-6 per margetuximab dose) (margetuximab 15 mg/kg q3W (margetuximab 15 mg/kg q3W + pembrolizumab 200 mg q3W) + pembrolizumab 200 mg q3W) Margetuximab 10 – 15 mg/kg q3w + pembrolizumab 200 mg q3w Data presented at ASCO GI 2019 Gastric and Gastroesophageal (n=60)

Gastric (HER2 3+) (n=25) Clinical Supply Agreement

• Potential for chemotherapy-free regimen Treatment • Margetuximab and pembrolizumab administered day 1 of every 3 week cycle • Received ≥ 1 prior line of chemotherapy treatment Inclusion/Exclusion Criteria • No prior immunotherapy • Primary: safety, tolerability and efficacy (as evaluated by objective response rate (ORR)) of combo Endpoints • Secondary: PFS, OS, immunogenicity

16 June 5, 2019 Margetuximab Promising Activity in Gastric Cancer Population(a) 33% ORR in HER2 3+ gastric cancer PD-L1 Negative 120 PD-L1 Positive 100 Status Unknown 80 Ongoing 60 40 20 0 -20

-40 Change from Baseline (%) Baseline from Change -60 Gastric Cancer N ORR DCR mPFS mOS -80 HER2 IHC 3+(b) 55 32.7% (18/55) 69.1% (38/55) 4.70 (2.66, 7.49) NR (12.48, NR) -100 IHC3+/PD-L1+(c) 23 52.2% (12/23) 82.6% (19/23) 4.14 (2.60, 15.54) NR (6.74, NR)

(a) Data cut-off January 8, 2019. Includes patients who received at least one margetuximab and pembro dose in expansion phase, and had baseline measurable disease and at least one post-baseline disease assessment. (b) Immunohistochemistry (IHC) test gives score of 0 to 3+ that measures amount of HER2 receptor protein on surface of cells in cancer tissue sample. Score of 0 to 1+ is called “HER2 negative”, score of 2+ is called "borderline“, score of 3+ is called “HER2 positive.” (c) “PD-L1 Positive” reflects Combined Positive Score (per standard FDA approved assay) ≥1% (PD-L1 tested on archival tissue by IHC; clone 22C3 pharmDx).

17 June 5, 2019 Margetuximab Margetuximab + Anti-PD-1 Data in 2L Presents Opportunity to Advance to 1L HER2+ gastric cancer benchmarks 1st Line 2nd Line 3rd Line SOC SOC Ongoing Study Failed Ongoing Study Trastuzumab + Ramucirumab Margetuximab+ Agent Pembrolizumab(d) Chemo(a) + Paclitaxel(b) Pembrolizumab(c) DS-8201(e) (Study) (KEYNOTE-61) (TOGA) (RAINBOW) (Ongoing Ph. 2) 33% 15.8% ORR 47% 28% 43% (52% in PD-L1+) (PD-L1+)

Median PFS 6.7 mos. 4.4 mos. 4.7 mos. 1.5 mos. 5.6 mos.

16.8 mos. IHC 3+ GC; Median OS 13.1 mos. 9.6 mos. (IHC3+/PD-L1+ 9.1 mos. NA not reached) Overall: N/A 41% Neutropenia 18% ≥ Grade 3 TRAEs 68% 14.3% 50.2%(e) 15% Hypertension (All GC+GEJ) 12% Fatigue

Gastric/GEJ 100%/0% 80/20% 80/20% Not disclosed NA Patient Mix (All IHC 3+ Gastric)

SOC = Standard of Care (a) Data from Herceptin package insert; Bang, et al., Lancet, 2010; (b) Data from Cyramza package insert; Wilkes, et al., Lancet Oncology, 2014; (c) Data presented at ASCO GI 2019; Median OS for HER2 IHC 3+ gastric cancer as of April 2019. (d) Data presented at ASCO 2018, Abstract 4062. (e) Powell, et al., SABCS 2018, Poster P6-17-06, at 5.4 mg/kg dose in breast cancer patients (n=269), 5 cases of ILD reported, 2 x Gr1, 2 x Gr2, and 1 x Gr5; ILD is a well-characterized risk.

18 June 5, 2019 Margetuximab MAHOGANY Phase 2/3 Study: Registration Path in 1L Gastric & GEJ Cancer Margetuximab in HER2-positive Gastric Cancer

Margetuximab + Anti-PD-1 (Chemo-free Regimen)

(n=40) (add’l patients to support potential AA) HER2+ (IHC 3+) Primary Single Experimental Arm: Single Experimental Arm: Go/ Endpoint: and margetuximab + MGA012 No Go margetuximab + MGA012 ORR Module A Module PD-L1+ (≥1% CPS) ORR and Tolerability

Margetuximab + Chemo + MacroGenics Checkpoint Inhibitor (n=50 per arm) Standard of Care: trastuzumab+ chemo (n=250 per arm) HER2+ Experimental Arm #1: Standard of Care: (IHC 3+ or margetuximab + chemo + MGA012 Trastuzumab + chemo Primary Futility Endpoint: BLA IHC 2+/FISH+) R Analysis R regardless of Experimental Arm #2: Experimental Arm: OS

ModuleB marge + chemo + CPI* PD-L1 status margetuximab + chemo + MGD013 Assess Safety/efficacy of Experimental Arm #3: Experimental margetuximab + chemo Arms #1 and #2

* Pending chronic tox study (if regimen with MGD013 is selected).

19 June 5, 2019 MGA012 MGA012: Initial Activity Profile Similar to Approved Anti-PD-1 mAbs Global collaboration with Incyte; significant development effort across multiple studies

Function/ • Humanized, hinge-stabilized IgG4 mAb MoA • Inhibits PD-1

PD-1 PD-1 • Eleven monotherapy/combo studies ongoing • Initial monotherapy data projected in 2020(a) Status • Planned combination with margetuximab ± chemo in Phase 2/3 MAHOGANY study in gastric cancer

• $150M Upfront cash payment Global Incyte • Up to $750M in milestones ($15M received in 2018) Transaction • Tiered royalties of 15-24% on future MGA012 sales

MacroGenics’ • Develop pipeline assets in combination with MGA012 Retained Rights • Manufacture portion of global MGA012 supply

(a) Ongoing studies in MSI-high endometrial cancer, Merkel cell carcinoma and anal cancer are potentially registration-directed.

20 June 5, 2019 MGA012 MGA012: Building a Pipeline within a Product Monotherapy Studies Combination Studies Registration Intent(a) Multiple tumors

MSI-High Merkel Cell Anal Epacadostat Parsaclisib Endometrial Cancer Carcinoma Cancer (IDO1) (PI3Kδ)

~8,500 ~1,300 ~5,000 Pemigatinib INCB01158 patients/year patients/year patients/year (FGFR) (Arginase)

Pembro Avelumab Pembro/Nivo Initiated provides POC provides POC provide POC MGD007 MGD009 Data Expected Data Expected Data Expected (gpA33 × CD3) (B7-H3 × CD3) 2020 2020 2021

Multiple Benchmarking Studies Ongoing Margetuximab Enoblituzumab (HER2) (B7-H3) Non-small Cell Lung Melanoma Renal Carcinoma Urothelial Cancer Cancer ± Chemo Cervical Cancer Soft Tissue Sarcoma Endometrial Cancer

Flotetuzumab MGC018 Planned (CD123 × CD3) (B7-H3 ADC)

(a) Epidemiological estimates are for US, EU and Japan. Source: Incyte Corporation.

21 June 5, 2019 MGD013 MGD013: First Bispecific Checkpoint Molecule in Clinic

• Simultaneous and/or independent blockade of two Function/ MoA checkpoint molecules • Reactivation of exhausted T cells LAG-3 LAG-3

PD-1 PD-1 • Patients with solid and liquid tumors: Clinical – Progressed on prior checkpoint inhibitor Development – Checkpoint-naïve

• Ongoing Ph. 1 dose expansion in nine tumor types • Exploring correlative biomarkers (with Nanostring) Status • Initiating Phase 2/3 MAHOGANY study with margetuximab and chemotherapy in gastric cancer

MacroGenics’ Retained • Global rights (excl. Greater China) Rights

22 June 5, 2019 MGD013 Rationale for MGD013 in MAHOGANY Phase 2/3 Study: High LAG-3 Expression

• LAG-3 positivity: 88% (30/34) observed across gastric cancer samples*

H&E and LAG-3 IHC profile for gastric cancer patient sample 20x H&E LAG-3 IHC Isotype Control

• cPR in 67 y.o. gastric cancer patient in MGD013 monotherapy Phase 1 study − Refractory to nivolumab − Complete resolution of target lesions − Treatment ongoing as of May 2019 for ~31 weeks

* IHC performed using anti-LAG-3 mAb EPR43292(2); Positivity defined as detection of at least one LAG-3 positive Tumor Infiltrating Lymphocyte (TIL)

23 June 5, 2019 Enoblituzumab Enoblituzumab: Potential Leading Anti-B7-H3 mAb Leveraging immune modulation through Fc optimization

• Fc region optimized to enhance immune response, Function/ including ADCC MoA • Evidence of T-cell immunomodulation B7-H3 B7-H3 • 1st Line SCCHN cancer Fab Clinical Region • 1st Line NSCLC (including PD-L1 negative) Development • Others under consideration

• Planning to initiate Phase 2 study in SCCHN in Status Fc Region combination w/ MGA012 (anti-PD-1 mAb) in 2H19

MacroGenics’ Retained • Global rights Rights

24 June 5, 2019 Enoblituzumab Antitumor Activity in SCCHN Patients (Anti-PD-1/PD-L1 Naïve) Induction of tumor regression in SCCHN patients, irrespective of HPV status HPV- 60 HPV+ First new lesion 40 Treatment ongoing 20 0 HPV- -20 50 HPV+ -40 40 * Treatment ongoing -60 30 -80 20 Change from Baseline (%) -100 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 10 Weeks Since Treatment Indication 0 -10 * -20 -30 -40 -50 All Patients B7-H3 (Tumor) ≥ 10% -60 * -70 N= 18 15 -80 CR+PR 6/18 (33.3%) 6/15 (40.0%) -90 * CR+PR+SD 11/18 (61.1%) 11/15 (73.3%) -100 * Source: SITC 2018 Oral Presentation O24; Data cut-off date: October 12, 2018

25 June 5, 2019 Enoblituzumab Antitumor Activity in NSCLC Patients (Anti-PD-1/PD-L1 Naїve) Induction of tumor regression in NSCLC patients with <1% PD-L1

100 Squamous 80 Non-squamous 60 First new lesion Treatment ongoing 40 20 0 50 Squamous -20 40 Non-squamous -40 Treatment ongoing -60 30 -80

* Change from Baseline (%) 20 -100 0 5 10 15 20 25 30 35 40 45 50 55 60 65 10 Weeks Since Treatment Indication 0 -10 -20 * -30 -40 * -50 All Patients B7-H3 (Tumor) ≥ 10% -60 * -70 N= 14 11 -80 CR+PR 5/14 (35.7%) 5/11 (45.4%) -90 CR+PR+SD 13/14 (92.9%) 10/11 (90.9%) -100 *

Source: SITC 2018 Oral Presentation O24; Data cut-off date: October 12, 2018

26 June 5, 2019 Enoblituzumab Encouraging Enoblituzumab + Anti-PD-1 Combo Data

SCCHN Study Results Agent Enoblituzumab Nivolumab Pembrolizumab Pembrolizumab (Study) + Pembrolizumab (CM-141)(a) (KN-012)(b) (KN-040)(c) N 18 240 174 247 ORR 33.3% 13% 16% 15%

NSCLC Study Results Agent Enoblituzumab Nivolumab Nivolumab Pembrolizumab (Study) + Pembrolizumab (CM-057)(d) (CM-017)(e) (KN-001)(f) Histology Both Non-Squamous Squamous Both PD-L1 Status PD-L1<1% PD-L1<1% PD-L1<1% PD-L1<1% N 14 108 54 87 ORR 35.7% 9% 17% 8%

(a) Ferris, et al., 2016, N Eng J Med (b) Keytruda® package insert (c) Cohen, et al., 2017, ESMO LBA45 (d) Borghaei, et al., 2015, NEJM (e) Brahmer, et al., 2015, NEJM (f) Garon, et al., 2015, NEJM

27 June 5, 2019 Flotetuzumab Flotetuzumab: CD123 × CD3 DART Molecule

• Redirected T-cell killing against leukemia cells Function/ – Eliminates leukemic stem cells MoA – Spares normal hematopoietic stem cells – Engages any T-cell without HLA-restriction

• Acute Myeloid Leukemia (AML) CD123 CD3 Clinical Development • Other hematologic neoplasms, including B-cell ALL under consideration

• ASH 2018 oral presentation • Ongoing/future studies will: Status – Enrich for primary refractory and biomarker- selected AML patients – Evaluate combo with MGA012 (anti-PD-1 mAb)

MacroGenics’ • MacroGenics: exclusive rights in North America, Japan, Retained Korea and India Rights • Servier: exclusive rights in other territories

28 June 5, 2019 Flotetuzumab Primary Refractory AML Patients Have Been Most Responsive to Flotetuzumab Dose expansion #1 data presented at ASH 2018

50 Primary Refractory 40 Relapsed Median Duration of 30 Failed 2 Cycles of HMA Response = 3.1 mos. 20 10 SD SD SD SD SD SD SD SD SD SD SD PR(b) MLF CR CR CR CRi CRi(a) 0 -10 PD PD PD PD PD PD PD -20 -30 -40 -50 Benchmark AML Population ORR CR/CRi CR/CRi -60 -70 Primary Refractory 6/17 (35.3%) 5/17 (29.4%) 13%(c) -80 -90 Relapse 1/7 (14.3%) 0/7 (0%) —

Bone Marrow Blast Change from Baseline (%) Baseline from Change Marrow Blast Bone -100 • 31 Patients treated at RP2D: 27 response evaluable (2 PD on PB blasts), 25 pts in waterfall plot • 3 Patients non-evaluable pts (2 pts withdrew consent, 1 pt. withdrawn due to TRAE); 1 pt. ongoing • Acceptable safety: primarily low-grade CRS, w/Grade 3=12.9% (4/31 patients)

Source: ASH 2018 Oral Presentation #764; Data cut-off date: Nov. 1, 2018 CR=Complete Response; CRi=Complete Response with incomplete hematological improvement; MLF=Morphologic Leukemia-free state; PR=Partial Response; SD=Stable Disease; PD=Treatment Failure (a) Patient subsequently underwent HSCT in remission (b) Patient with PR had duration of response = 1.4 months (c) CR/CRp rate reported by Kantarjian, et al. (Cancer 2018) in large-scale analysis of chemotherapy-based salvage therapy in primary refractory AML patients

29 June 5, 2019 Financial Overview

• $320M Cash, cash equivalents and marketable securities as of March 31, 2019 • Historical financial details: Qtr. Ended March 31, $ in Millions 2014 2015 2016 2017 2018 2019 2018 Total Revenues $48 $101 $92 $158 $60 $10 $5 R&D Expense 70 98 122 147 191 47 46 Total Operating Expenses 86 121 152 180 231 57 55 Cash & Investments 158 339 285 305 233 320 260

• Revenues from collaborative and government agreements (>$450M since 2013 IPO):

$150

$100

$50 $ in Millions in $

$0 2014 2015 2016 2017 2018

30 June 5, 2019 Anticipated Development Progress of Core Product Candidates in 2019

Margetuximab Enoblituzumab (Anti-HER2 mAb) (Anti-B7-H3 mAb)

✓ Positive Topline SOPHIA PFS data  Initiate MGA012 combo study (2H) ✓ Updated gastric combo data  Initiate gastric combo study (2H)

MGA012(a) MGD013 Flotetuzumab (Anti-PD-1 mAb) (PD-1 × LAG-3 DART) (CD123 × CD3 DART)

(Subject to Incyte’s disclosure)  Present clinical update  MGA012 combo study planned  Present additional mono. data

(a) MacroGenics retains rights to develop its pipeline assets in combination with MGA012 and to manufacture a portion of global clinical and commercial supply needs of MGA012.

31 June 5, 2019 Thank You!

Investor Relations Inquiries: Jim Karrels – Senior Vice President, CFO 301-354-2681 | [email protected] Anna Krassowska, Ph.D. – Vice President, Investor Relations and Corporate Communications 301-461-4042 | [email protected]

Business Development Inquiries:

Eric Risser – Senior Vice President, Chief Business Officer 301-354-2640 | [email protected]

www.macrogenics.com Link to our latest presentations: http://ir.macrogenics.com/events.cfm

32 June 5, 2019