Corporate Presentation September 2020 Forward Looking Safe Harbor - PowerPoint PPT Presentation

Corporate Presentation September 2020

Forward Looking Safe Harbor Statement This presentation may contain “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, each as amended. These statements are often, but not always, made through the use of words or phrases such as “anticipates”, expects”, plans”, believes”, “intends”, and similar words or phrases. Such statements involve risks and uncertainties that could cause Mustang Bio’s actual results to differ materially from the anticipated results and expectations expressed in these forward-looking statements. These statements are only predictions based on current information and expectations and involve a number of risks and uncertainties. Actual events or results may differ materially from those projected in any such statements due to various factors, including the risks and uncertainties inherent in clinical trials, drug development, and commercialization. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement and Mustang Bio undertakes no obligation to update these statements, except as required by law. 2

▪ Mustang (NASDAQ:MBIO) is focused on developing next-generation therapies for patients with cancer and rare genetic diseases ▪ Transformational ex vivo lentiviral gene therapy for XSCID licensed from St. Jude – Highly compelling results in 2 ongoing clinical trials led by St. Jude & NIH – Targeting approval of Mustang INDs for both programs 4Q2020 Mustang Bio: ▪ Lead CAR-T targeting CD20 is generating early encouraging results in lymphoma Building a Fully – Targeting disclosure of phase 1 data in December at ASH Integrated Gene & Cell – Anticipate filing Mustang IND 1Q2021 for pivotal phase 1/2 trial in NHL & CLL – 5 COH CAR-Ts also in phase 1 trials; first Mustang IND trial targets CD123, now enrolling Therapy Company ▪ Phase 1 oncolytic virus from Nationwide to enhance CAR-T activity in glioblastoma ▪ 27,000 square foot cell processing & translational research facility on UMass Medical School campus with capacity to launch at commercial scale ▪ Team with extensive gene & cell therapy industry experience 3

Leadership Team with Extensive Gene, Cell & Rare Disease Therapy Experience Knut Niss, PhD Debra Manning, SPHR Manuel Litchman, MD Brian Achenbach, MBA Lynn E. Bayless, MS VP, Human Resources President & Chief Chief Technology SVP, Finance & Head, Regulatory Officer Executive Officer Corporate Controller Affairs James Edinger, PhD Regan Flynn, SHRM-CP Greg Furrow, MS, FRQA Scott Smith, MBA Executive Assistant / VP, Preclinical Senior Director, Alliance VP, Quality Sciences HR Generalist & Program Mgmt 4

R&D Collaborators: World Class Team of Scientific Experts ▪ Technology licensed from City of Hope (COH), Fred Hutch Cancer Research Center (FHCRC), Nationwide Children’s Hospital, & St. Jude Children’s Research Hospital ▪ Research based on pioneering work by: Dr. Stephen Forman Dr. Christine Brown Dr. Brian Till Dr. Kevin Cassady Dr. Brian Sorrentino SJCRH City of Hope City of Hope FHCRC Nationwide (1958-2018) 5

Robust Pipeline of Therapies Addressing Highly Challenging Diseases Therapeutic Target 2020 2021 2022 2023 Modality (Partner) Ex-vivo Ph 1 CMC Hold: Pivotal Phase 2 XSCID newly diagnosed (Mustang IND) IL2RG Gene (St. Jude) Therapy Pivotal Phase 2 XSCID previously transplanted (Mustang IND) Ph 1 at NIH Ph 1 CD123 (2019) Pivotal Phase 1/2 Blastic plasmacytoid dendritic cell neoplasm (Mustang IND) [AML & hrMDS may be added at higher dose levels] Hematologic (COH) CAR-Ts CD20 Pivotal Ph 1/2 Non-Hodgkin lymphoma & chronic lymphocytic leukemia (Mustang IND) Phase 1 NHL at FHCRC (FHCRC) IL13R α 2 Phase 1 Glioblastoma multiforme: CAR-T + nivolumab ± pretreatment with nivolumab and ipilimumab at COH* (COH) IL13R α 2 Phase 1 GBM: CAR-T for leptomeningeal disease at COH Solid Tumor (COH) CAR-Ts C134 OV Phase 1 GBM at UAB* Ph 1 + CAR-T at COH Phase 1/2 GBM: CAR-T + oncolytic virus (Mustang IND) (Nationwide) PSCA Phase 1 Prostate cancer at COH* Phase 1/2 Prostate & pancreatic cancer (Mustang IND) (COH) St. Jude = St. Jude Children’s Research Hospital XSCID = X-linked severe combined immunodeficiency Mustang files new IND NIH = National Institutes of Health AML = Acute myelogenous leukemia COH = City of Hope National Medical Center hrMDS = High-risk myelodysplastic syndrome COH files new IND FHCRC = Fred Hutchinson Cancer Research Center NHL = Non-Hodgkin lymphoma Nationwide = Nationwide Children’s Hospital Topline data available GBM = Glioblastoma multiforme UAB = University of Alabama at Birmingham OV = Oncolytic virus * Partially or totally supported by grants 6

Cell Processing: A Core Competency & Competitive Advantage ▪ Facility was built & fully operational prior to enrolling first patient on Mustang IND trial ▪ Universal platform process developed for autologous CAR-Ts; 1 st patient’s cells expected 3Q2020 Day -1 Day 0 Day 2 Day 3 Day 7 Day 15+ Day 19+ 8-day sterility Leukapheresis Infusion Enrichment Transduction Expansion Fill Shipment CoA Shipment Activation Wash Harvest Cryopreservation Thawing Direct Labor (h) for 10 processes Direct raw material cost (excl. LV) 120 90 100 80 70 % Company A 80 60 FTE Sum 50 60 40 40 30 CD123 CS1 20 20 10 0 0 A B C D E F MBIO 0 1 2 3 4 5 6 7 Leading Companies & Academic Institutions Process Day ▪ Deep expertise of our people leveraged to also process XSCID patients’ cells starting 4Q2020 7

Mustang’s Manufacturing Site – Current West Wing Space East Wing now office & storage space; clean rooms & labs to be build out in 2021 Landlord: UMass Lease Start: Oct 2017 Cleanroom space Duration: 9 years Labs (QC/PD and Research) Office Master Site File with FDA as part of MB-102 IND (open) 8

Mustang Milestones over Next 12 Months Therapy Asset Event Expected Event Timing Type (Target) Type Trial Start Resolve CMC hold, begin accrual to pivotal trial in newly diagnosed XSCID pts Q4 Gene MB-107, Therapy MB-207 IND Filing File Mustang IND for pivotal trial in previously transplanted XSCID patients Q4 Data Potential first data at ASH from FHCRC trial in NHL Q4 MB-106 (CD20) IND Filing Tech transfer from FHCRC and prepare for Mustang IND filing for NHL and CLL Q1’21 MB-105 Data Potential first data from COH trial in prostate cancer Q2’21 (PSCA) CAR-T Trial Start Treat first patient in Mustang IND multicenter trial for BPDCN, AML, & hrMDS Q3 MB-102 (CD123) Data Potential follow-up data from COH trial in AML & BPDCN Q2’21 MB-101 IND Filing Support COH IND filing for combination trial with MB-108 oncolytic virus for GBM Q4 (IL13R α 2) 9

X-Linked Severe Combined Immunodeficiency (XSCID): Profound deficiency of T, B & NK Cell Immunity Due to Mutations in the IL2RG Gene 1 XSCID ▪ IL2RG codes for common gamma chain (  c) – critical for development of normal immune cells or 21 X IL-2, 4, Mutated ▪ Early diagnosis & treatment possible in areas with newborn 7, 9, 15 β  c screening (NBS) or in patients with family history chain Common  chain ▪ In the absence of NBS, most patients (almost all males) are diagnosed at 3 – 6 months when maternal immunity wanes – Recurrent bacterial, viral and fungal infections – Diarrhea, protein-losing enteropathy, failure to thrive ▪ Death by age 1 if untreated ▪ Standard of care is immune reconstitution via allogeneic hematopoietic stem cell transplant (HSCT) Interleukin receptor 1. Fischer A et al. Nat Rev Dis Primers. 2015 (Oct 29);1:15061. 10

XSCID Is the Most Common Form of Combined Immunodeficiency 1 Newly-diagnosed infants: Worldwide annual incidence of ~1:225,000 live births ▪ US: ~20 new cases per year ▪ Rest of world: ~55 new cases per year in high/mid-income ex-US markets “ Reservoir ” (patients with XSCID who have been previously treated with allogeneic HSCT and who therefore might be eligible for gene therapy now or in the future) ▪ High/mid-income ex- US markets ≈ 650 patients ▪ US ≈ 400 patients ▪ Newborn screening for SCID is available in all 50 states, D.C., & Puerto Rico 2,3 ▪ Very few countries outside the US have nationwide newborn screening for SCID 4 1. Third-party analysis based on NBS data, medical literature, registry data & KOL interviews. Addressable ex-US markets include Canada & mid to high income countries in Europe, Asia, Latin America & Middle East. 2. https://primaryimmune.org/idf-advocacy-center/idf-scid-newborn-screening-campaign. 3. http://www.scid.net/the-scid-homepage/newborn-screening-where-it-began. 4. Meehan C et al. Rev Paul Pediatr. 2018;36:388-397. 11