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

Corporate Presentation June 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 a publicly-traded biotechnology company focused on developing next-generation medicine in areas of high patient need ▪ Transformational ex vivo lentiviral gene therapy for XSCID licensed from St. Jude – Promising results in 2 ongoing clinical trials led by St. Jude & NIH Mustang Bio: ▪ 6 CAR-T programs from City of Hope & Fred Hutchinson Cancer Research Center, all potentially first in class Building a Fully – All in Phase 1 trials, with first Mustang IND program to start enrolling 2Q2020 Integrated Gene & Cell – Targets include: CD20, PSCA, IL13R α 2, CD123, CS1, and HER2 Therapy Company ▪ Phase 1 oncolytic virus from Nationwide to enhance CAR-T activity in glioblastoma ▪ Targeting 2 additional Mustang IND approvals in 2020 ▪ 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 John Bernard, MD Manuel Litchman, MD Brian Achenbach, MBA Lynn E. Bayless, MS VP, Human Resources President & Chief Chief Technology SVP, Finance & Senior Medical Head, Regulatory Officer Director Executive Officer Corporate Controller Affairs James Edinger, PhD Regan Flynn, SHRM-CP Scott Smith, MBA Greg Furrow, MS, FRQA 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 Gene & Cell Therapies Addressing Rare Conditions Therapeutic Target 2020 2021 2022 2023 Modality (Partner) Pivotal Phase 2 X-SCID newly diagnosed Ph 1 (Mustang IND) Ex-vivo IL2RG Gene Therapy (St. Jude) Pivotal Phase 2 X-SCID previously transplanted Ph 1 Ph 1 (Mustang IND) CD123 Pivotal Phase 1/2 Blastic plasmacytoid dendritic cell neoplasm (BPDCN) (Mustang IND) Hematologic Malignancies (COH) [acute myelogenous leukemia (AML) & high-risk myelodysplastic syndrome (hrMDS) may be added at higher dose levels] Pivotal Ph 1/2 NHL & chronic lymphocytic leukemia CD20 Phase 1 Non-Hodgkin lymphoma (Mustang IND) (FHCRC) (NHL) at FHCRC Ph 1 Multiple myeloma (MM) at Pivotal Phase 1/2 Multiple myeloma CS1 COH (Mustang IND) (COH) CAR-T Phase 1 GBM: CAR-T + nivolumab ± pretreatment with nivolumab and ipilimumab at COH* IL13Rα2 Therapy (COH) Phase 1 GBM: CAR-T for leptomeningeal disease at COH C134 OV Phase 1/2 GBM: Phase 1/2 GBM: CAR-T + oncolytic virus (OV) Tumors Phase 1 GBM at UAB* Solid (Nationwide) CAR-T + OV at COH (Mustang IND) PSCA Phase 1/2 Prostate & pancreatic cancer Phase 1 Prostate cancer at COH* (Mustang IND) (COH) Phase 1/2 Metastatic HER2+ cancer to brain HER2 Phase 1 GBM & metastatic HER2+ cancer to brain at COH* (Mustang IND) (COH) St. Jude = St. Jude Children’s Research Hospital Mustang files new IND GBM = Glioblastoma multiforme Nationwide = Nationwide Children’s Hospital COH = City of Hope National Medical Center COH files new IND FHCRC = Fred Hutchinson Cancer Research Center UAB = University of Alabama at Birmingham Topline data available 6 * Partially or totally supported by grants

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 2Q2020 Day -1 Day 0 Day 2 Day 3 Day 7 Day 15+ Day 19+ 8 day sterility Leukapheresis Enrichment Transduction Expansion Fill Shipment Infusion 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 AND ACADEMIC INSTITUTES Process Day ▪ Deep expertise of our people leveraged to also process XSCID patients’ cells starting 3Q2020 7

Mustang Milestones over Next 12 Months Therapy Type Asset (Target) Event Type Expected Event Timing 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 (PSCA) Data Potential first data from COH trial in prostate cancer Q4 Trial Start Initiate enrollment in Mustang IND multicenter trial for BPDCN, AML, & hrMDS Q2 MB-102 (CD123) CAR-T Data Potential follow-up data from COH trial in AML & BPDCN Q4 Data Potential first data from COH trial in multiple myeloma Q4 MB-104 (CS1) IND Filing Tech transfer from COH and prepare for Mustang IND filing for multiple myeloma Q1’21 MB-101 IND Filing Support COH IND filing for combination trial with MB-108 oncolytic virus for GBM Q4 (IL13R α 2) Oncolytic Virus MB-108 Data Potential first data from UAB trial for GBM as monotherapy Q4 Submit requests for Rare Pediatric Disease and Orphan Drug Designations for both target patient Reg Filing Q2 populations MB-107, MB- Gene Therapy Trial Start Begin patient accrual to newly diagnosed XSCID patients trial Q3 207 IND Filing File Mustang IND for multicenter trial in previously transplanted XSCID patients Q3 8

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 normal development, maturation and function of immune cells or 21 X ▪ Early diagnosis & treatment possible in areas with newborn IL-2, 4, Mutated 7, 9, 15 screening (NBS) or in patients with family history β  c chain Common ▪ In the absence of NBS, most patients (almost all males) are  chain diagnosed at 3 – 6 months when maternal immunity wanes – Recurrent bacterial, viral and fungal infections: Oral/diaper candidiasis, severe bacterial infections, opportunistic organisms such as Pneumocystis – 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. 9

XSCID Is the Most Common Form of Combined Immunodeficiency 1 Newly-diagnosed infants ▪ US estimated annual incidence of ▪ Rest of world annual incidence is similar to US ~1:225,000 live births ~1:225,000 live births ▪ ~20 new cases per year ▪ ~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. 10