RAG-1

uBriGene (Boston) Biosciences to acquire Mustang Bio’s Worcester manufacturing facility for total consideration of up to $11 million and enters into strategic manufacturing partnership to support MB-106 and future pipeline Company optimizes resources to focus on advancing lead CD20 CAR T program, GBM program, and in vivo CAR T platform technology from Mayo Clinic Transaction and partnership with uBriGene, portfolio optimization, restructuring and recent loan repayment expected to significantly reduce annualized operating and interest expense by at least $28 million and ensure focus on data readouts for key programs WORCESTER, Mass., May 18, 2023 (GLOBE NEWSWIRE) --Mustang Bio, Inc. (“Mustang” or the “Company”) (Nasdaq: MBIO), a clinical-stage biopharmaceutical company focused on translating today’s medical breakthroughs in cell and gene therapies into potential cures for difficult-to-treat cancers and rare genetic diseases, today announced a strategic update, including anticipated milestones for 2023. Mustang intends to optimize the allocation of its resources and focus on MB-106, MB-109, and in vivo CAR T platform technology. Additionally, Mustang announced a partnership with uBriGene (Boston) Biosciences Inc. (“uBriGene”), the U.S. subsidiary of uBriGene Group, a leading cell and gene therapy contract development and manufacturing organization (“CDMO”), which includes the sale of the Company’s development, manufacturing and analytical testing facility in Worcester, Massachusetts to uBriGene. Under the terms of an asset purchase agreement between Mustang and uBriGene, uBriGene will acquire Mustang’s state-of-the-art clinical- and commercial-scale cell and gene therapy manufacturing facility in Worcester, Massachusetts, for a total consideration of $11 million. This consideration includes $6 million payable upfront plus an additional $5 million payable upon Mustang raising $10 million in gross proceeds from equity raises following the closing of the transaction. The closing of the transaction is subject to the satisfaction of certain conditions, including approval of transfer of the Company’s lease to uBriGene by the owner of the building (an affiliate of the University of Massachusetts Chan Medical School) and the acceptance of offers of employment with uBriGene or its affiliates by certain key current Mustang employees. Subject to satisfaction of conditions, the Company expects the transactions to close in June 2023. Subject to closing, the parties will enter into a manufacturing supply agreement, under which uBriGene will manufacture Mustang’s lead product candidates, including continuing to support MB-106 manufacturing for the ongoing multi-center Phase 1/2 trial. Mustang’s Worcester facility is a 27,000 square foot, cutting edge cGMP facility supporting process development, manufacturing and analytical testing, designed with the flexibility to expand and support various cell and gene therapy production requirements and capacities. uBriGene intends to expand the Worcester site’s capabilities while leveraging Mustang’s experienced staff and robust quality and operating systems to manufacture a broader portfolio of advanced modalities. uBriGene will also offer their expertise in preclinical research services and late-stage and commercial manufacturing of advanced therapy products with respect to product and process characterization, and regulatory inspections. Manuel Litchman, M.D., President and Chief Executive Officer of Mustang, commented, “We are very pleased to have found a great partner for the manufacturing of our CAR T cell and gene therapies, and we believe that this strategic partnership with uBriGene will meet our portfolio manufacturing needs to reach critical upcoming data inflection points, while extending our cash runway. I want to thank our manufacturing team for their dedication in building and growing our Worcester facility since it opened in 2018. While we are optimizing our resources at Mustang, we look forward to continuing to work with many of our colleagues in this new capacity, as our CDMO.” “This acquisition is important to uBriGene’s commitment to support the development, clinical, and commercial supply of cell and gene therapies to sustain industry demand and provide new CDMO options,” said Alex Chen, President of uBriGene. “We look forward to working together with the University of Massachusetts Chan Medical School and local biotechnology companies to continue to advance the manufacturing ecosystem in the Greater Boston region. This partnership enables us to expand rapidly to create a North American presence and offer the same high-quality cell and gene therapy development and manufacturing capabilities for the U.S. that we currently provide in Asia, including to support Mustang Bio’s lead clinical-stage CAR-T program.” Mustang Bio Strategic Portfolio Updates CAR T Cell Therapies After a review of its portfolio of product candidates to determine the future strategy of its programs and the proper allocation of its resources, Mustang will discontinue development of its MB-102, its CD123-targeted CAR T cell therapy, as well as its HER2-, CS1- and PSCA-targeted CAR T cell therapy programs, comprising a portion of the Company’s portfolio of CAR T cell therapies being developed by the Company in partnership with City of Hope. Mustang will continue to work with Fred Hutchinson Cancer Center (“Fred Hutch”) to develop MB-106 (CD20-targeted CAR T cell therapy) and with Mayo Clinic to develop its in vivo CAR T platform technology. Mustang will also continue to work with City of Hope and with Nationwide Children’s Hospital on the development of MB-109 (MB-101 CAR T cell therapy targeting IL13Rα2 on malignant glioma cells + MB-108 oncolytic virus to potentially make these tumors more susceptible to killing by the CAR-T cells). Gene Therapies Additionally, based on a review of the data from the investigator-sponsored clinical trials of the gene therapy for X-linked severe combined immunodeficiency (“XSCID”) that has been licensed to Mustang Bio, enrollment to these trials has been paused. We await data from new investigator-sponsored trials being planned by our partners that will test a modified version of the current lentiviral vector prior to initiating multicenter Mustang-sponsored trials in both the newborn and previously transplanted patient populations. No safety concerns in the trials utilizing the current vector have been noted to date and no insertional mutagenesis or malignancy has been detected in either of the two investigator-sponsored trials. However, Mustang has made the decision to delay initiating its own sponsored trials out of an abundance of caution, and once we have had the opportunity to review the emerging data from the planned trials utilizing the modified vector, Mustang expects to provide more information on timelines. The delayed start of Mustang’s multicenter trials for XSCID will allow the Company to utilize the safest known vector available in its clinical trials and reduce Mustang’s near-term operating expense. In addition, in 2023 we look forward to treating a second RAG1-SCID patient with our MB-110 LV-RAG1 ex vivo lentiviral gene therapy in the ongoing investigator-sponsored Phase 1/2 multicenter clinical trial taking place in Europe. Furthermore, we hope to provide an update regarding the research collaboration with Frank J. Staal, Ph.D., from Leiden University to develop additional lentiviral gene therapies. “Upon completion of a thorough, strategic review of our portfolio of CAR T and gene therapies, it was determined that Mustang’s resources should be focused and allocated to benefit our lead clinical-stage CAR T programs, which could provide potential curative treatment options for certain hematologic cancers and solid tumors, supported by data-to-date. As previously reported, MB-106 continues to demonstrate high efficacy and a favorable safety pro a Phase 1 investigator-sponsored trial at Fred Hutch, with an overall response rate of 96% and complete response rate of 75% in a wide range of hematologic malignancies, including Waldenstrom macroglobulinemia (“WM”). Given this, Mustang plans to treat patients with WM in the Phase 1 portion of its multicenter MB-106 clinical trial to support a fast-to-market Phase 2 strategy for this indication, with the first pivotal Phase 2 WM patient potentially to be treated in the first quarter of 2024. Data from the Fred Hutch clinical trial also support the potential of MB-106 to be administered as outpatient therapy and provide a best-in-class immunotherapy option for patients treated previously with CD19-directed CAR T cell therapy. We look forward to data from the Fred Hutch clinical trial to be presented at medical meetings in the second quarter of 2023, and initial data from Mustang’s multicenter clinical trial to be disclosed shortly as well. Phase 1 clinical trials of MB-101 at City of Hope and of MB-108 at the University of Alabama at Birmingham continue to enroll patients with recurrent GBM. Additionally, Mustang is excited about advancing the preclinical investigation of these two programs as the combination therapy MB-109 and plans to IND for this therapy this year. Concentrating our priorities and postponing the initiation of the MB-107 and MB-207 pivotal trials, along with maintaining a reduced headcount, reduces Mustang’s burn and extends our cash runway. This allows Mustang to allocate more resources to advance our lead clinical-stage programs and potentially expedite the achievement of several near-term milestones across our portfolio of product candidates for difficult-to-treat cancers,” said Dr. Litchman. General Corporate Mustang expects to incur severance charges related to the facility transaction of approximately $2.1 million, which Mustang expects will be offset by future annualized operating savings of at least $24 million including savings related to personnel, facility and clinical operations and optimization of the development portfolio. The Company also reduced annual interest expense by approximately $4.3 million in April 2023 after repaying and terminating its Loan and Security Agreement with Runway Growth Finance Corp. About uBriGene (Boston) Biosciences Inc. uBriGene (Boston) Biosciences Inc. is dedicated to providing one-stop viral vector-based CDMO services for research and clinical applications. It has established integrated innovative biologics CDMO platforms that provide GMP-level plasmid preparation, viral packaging, and T-cell production services for large-scale CAR-T productions. In addition, the company also provides viral vectors, including adenoviral and lentiviral vectors to meet the demands of research and/or manufacturing applications. With its fermentation capacity ranging from 5L to 500L, uBriGene offers a versatile selection of research-grade, GMP-ready, or GMP-grade plasmids for research and clinical applications respectively. uBriGene currently operates two state-of-the-art GMP facilities, including 21 clean suites with a total area of over 133,000 sq ft. For more information, visit . About Mustang Bio Mustang Bio, Inc. is a clinical-stage biopharmaceutical company focused on translating today’s medical breakthroughs in cell and gene therapies into potential cures for hematologic cancers, solid tumors and rare genetic diseases. Mustang aims to acquire rights to these technologies by licensing or otherwise acquiring an ownership interest, to fund research and development, and to outlicense or bring the technologies to market. Mustang has partnered with top medical institutions to advance the development of CAR-T therapies across multiple cancers, as well as lentiviral gene therapies for severe combined immunodeficiency. Mustang’s common stock is registered under the Securities Exchange Act of 1934, as amended, and Mustang files periodic reports with the U.S. Securities and Exchange Commission (“SEC”). Mustang was founded by Fortress Biotech, Inc. (Nasdaq: FBIO). For more information, visit . Forward‐Looking Statements This press release contains “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. Such statements, which are often indicated by terms such as “anticipate,” “believe,” “could,” “estimate,” “expect,” “goal,” “intend,” “look forward to,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “will,” “would” and similar expressions. The Company’s forward-looking statements, include, among others, statements about the Company’s expectations with respect to the consummation of the sale of its manufacturing facility and its ability to fund its operations, including continued investment in its research and development pipeline; the Company’s anticipated savings and expenses relating to the consummation of the sale of its manufacturing facility, the discontinuance of its MB-102, its CD123-targeted CAR T cell therapy, as well as its HER2-, CS1- and PSCA-targeted CAR T cell therapy programs, the postponing of the MB-107 and MB-207 pivotal trials and the related reduction in the Company’s workforce; and the Company’s plans and timeline regarding its XSCID program. Actual events or results may differ materially from those described in this press release due to a number of risks and uncertainties. Risks and uncertainties include, among other things, risks related to the satisfaction of the conditions to closing the transaction—including the conditions specifically described in this press release—in the anticipated timeframe or at all; whether uBriGene is able to successfully perform its obligation to produce the Company’s products under the Manufacturing Services Agreement on a timely basis and to acceptable standards; whether the Company is able to raise $10 million in gross proceeds from equity raises following the closing of the transaction and receive the contingent portion of the consideration for the sale of the manufacturing facility to uBriGene; whether the Company’s expenses are as predicted; disruption from the transaction making it more difficult to maintain business and operational relationships; negative effects of the announcement or the consummation of the transaction on the market price of the Company’s common stock; significant transaction costs; the development stage of the Company’s primary product candidates and the related risks involved in drug development, clinical trials and the uncertainties around regulatory reviews and approvals; other business effects, including the effects of industry, market, economic, political or regulatory conditions; as well as other risks described in Part I, Item 1A, “Risk Factors,” in our Annual Report on Form 10-K filed on March 30, 2023, subsequent Reports on Form 10-Q, and our other filings we make with the SEC. We expressly disclaim any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in our expectations or any changes in events, conditions or circumstances on which any such statement is based, except as required by law, and we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995. Company Contact: Jaclyn Jaffe Mustang Bio, Inc. (781) 652-4500 ir@mustangbio.com Investor Relations Contact: Daniel Ferry LifeSci Advisors, LLC (617) 430-7576 daniel@lifesciadvisors.com Media Relations Contact: Tony Plohoros 6 Degrees (908) 591-2839 tplohoros@6degreespr.com

WORCESTER, Mass., Nov. 14, 2022 (GLOBE NEWSWIRE) -- Mustang Bio, Inc. (“Mustang”) (Nasdaq: MBIO), a clinical-stage biopharmaceutical company focused on translating today’s medical breakthroughs in cell and gene therapies into potential cures for hematologic cancers, solid tumors and rare genetic diseases, today announced financial results and recent corporate highlights for the third quarter ended September 30, 2022. Manuel Litchman, M.D., President and Chief Executive Officer of Mustang, said, “We continued to make progress advancing our portfolio of cell and gene therapies during the third quarter. Notably, we treated the first patient in our multicenter Phase 1/2 clinical trial to evaluate the safety and efficacy of MB-106, our first-in-class CD20-targeted, autologous CAR T cell therapy for the treatment of relapsed or refractory B-cell non-Hodgkin lymphomas (“B-NHL”) and chronic lymphocytic leukemia (“CLL”). This first clinical trial under Mustang’s Investigational New Drug application (“IND”) builds upon the initial, ongoing Phase 1/2 clinical trial taking place at Fred Hutchinson Cancer Center (“Fred Hutch”). In the Fred Hutch trial, MB-106 continues to demonstrate high efficacy and a favorable safety profile across patients with a wide range of hematologic malignancies. Results from the Waldenstrom macroglobulinemia (“WM”) cohort of the Fred Hutch trial were recently presented at the 11th International Workshop for Waldenstrom's Macroglobulinemia (“IWWM-11”), showing a 100% complete response (“CR”) rate in patients with WM. Our MB-106 program was granted Orphan Drug Designation (“ODD”) by the U.S. Food and Drug Administration (“FDA”) for WM, and we plan to treat additional patients with WM in the Mustang-sponsored Phase 1 portion of our multicenter trial in order to support a fast-to-market Phase 2 strategy for this indication. We anticipate announcing early results from the Mustang-sponsored Phase 1 trial in December 2022.” “In summary, our CD20 CAR T remains our lead program, and we believe the product profile is favorable compared to the approved autologous CAR Ts, which are generating an annualized run rate of $3 billion in net sales, based on reported sales in the third quarter of 2022,” said Dr. Litchman. Recent Corporate Highlights: In July 2022, Mustang announced that the first patient successfully received LV-RAG1 ex vivo lentiviral gene therapy to treat RAG1-SCID, in an ongoing Phase 1/2 multicenter clinical trial taking place in Europe. LV-RAG1 is exclusively licensed by Mustang for the development of MB-110, a first-in-class ex vivo lentiviral gene therapy for the treatment of RAG1-SCID.In October 2022, Mustang announced that the first patient was treated in its multicenter, open-label, non-randomized Phase 1/2 clinical trial evaluating the safety and efficacy of MB-106, Mustang’s first-in-class CD20-targeted, autologous CAR T cell therapy for the treatment of relapsed or refractory B-NHL and CLL. This is the first MB-106 clinical trial under Mustang’s IND.Also in October 2022, Mustang shared interim data from 28 patients treated in the initial, ongoing Phase 1/2 investigator-sponsored clinical trial at Fred Hutch. These data continue to support MB-106 as a viable CAR T cell therapy for B-NHLs and CLL. An ORR of 96% and CR rate of 75% were observed in a wide range of hematologic malignancies including follicular lymphoma (“FL”), CLL, diffuse large B-cell lymphoma, and WM. Twelve patients have experienced CR for more than 12 months (10 ongoing), including four patients with CR for more than two years and the longest patient with CR at 33 months. Six patients with initial partial response (“PR”) at 28 days post-treatment improved to CR, presumably due to the demonstrated persistence of CAR T cells in these patients, and all remain in ongoing CR. All three patients previously treated with CD19 CAR T cell therapy have responded to treatment with MB-106. A favorable safety profile for MB-106 as an outpatient therapy remains, with no cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome ≥ Grade 3.Additionally in October 2022, Mustang announced that results from the WM cohort and other interim data from the ongoing Phase 1/2 clinical trial of MB-106 at Fred Hutch were presented at IWWM-11 that took place in Madrid, Spain. Mustang’s MB-106 program was granted ODD by the FDA for WM, and Mustang plans to treat additional WM patients in the Mustang-sponsored Phase 1 portion of its multicenter trial in order to support a fast-to-market Phase 2 strategy for this indication.Mustang expects to announce early results from the Mustang-sponsored multicenter MB-106 trial later this quarter. Financial Results: As of September 30, 2022, Mustang’s cash and cash equivalents and restricted cash totaled $92.4 million, compared to $108.4 million at June 30, 2022 and $110.6 million as of December 31, 2021, a decrease of $16.0 million for the quarter and a decrease of $18.2 million year-to-date.Research and development expenses were $15.5 million for the third quarter of 2022, compared to $14.7 million for the third quarter of 2021. Non-cash, stock-based expenses included in research and development were $0.3 million for the third quarter of 2022, compared to $0.7 million for the third quarter of 2021.General and administrative expenses were $3.4 million for the third quarter of 2022, compared to $2.4 million for the third quarter of 2021. Non-cash, stock-based expenses included in general and administrative expenses were $0.2 million for the third quarter of 2022, compared to $0.3 million for the third quarter of 2021.Net loss attributable to common stockholders was $19.0 million, or $0.18 per share, for the third quarter of 2022, compared to a net loss attributable to common stockholders of $17.0 million, or $0.19 per share, for the third quarter of 2021. About Mustang BioMustang Bio, Inc. is a clinical-stage biopharmaceutical company focused on translating today’s medical breakthroughs in cell and gene therapies into potential cures for hematologic cancers, solid tumors and rare genetic diseases. Mustang aims to acquire rights to these technologies by licensing or otherwise acquiring an ownership interest, to fund research and development, and to outlicense or bring the technologies to market. Mustang has partnered with top medical institutions to advance the development of CAR T therapies across multiple cancers, as well as lentiviral gene therapies for severe combined immunodeficiency. Mustang’s common stock is registered under the Securities Exchange Act of 1934, as amended, and Mustang files periodic reports with the U.S. Securities and Exchange Commission (“SEC”). Mustang was founded by Fortress Biotech, Inc. (Nasdaq: FBIO). For more information, visit www.mustangbio.com. Forward‐Looking StatementsThis press release contains “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. Such statements, which are often indicated by terms such as “anticipate,” “believe,” “could,” “estimate,” “expect,” “goal,” “intend,” “look forward to,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “will,” “would” and similar expressions, include, but are not limited to, any statements relating to our growth strategy and product development programs, including the timing of and our ability to make regulatory filings such as INDs and other applications and to obtain regulatory approvals for our product candidates, statements concerning the potential of therapies and product candidates, and any other statements that are not historical facts. Forward-looking statements are based on management’s current expectations and are subject to risks and uncertainties that could negatively affect our business, operating results, financial condition and stock value. Factors that could cause actual results to differ materially from those currently anticipated include: risks relating to our growth strategy; our ability to obtain, perform under, and maintain financing and strategic agreements and relationships; risks relating to the results of research and development activities; risks relating to the timing of starting and completing clinical trials; uncertainties relating to preclinical and clinical testing; our dependence on third-party suppliers; our ability to attract, integrate and retain key personnel; the early stage of products under development; our need for substantial additional funds; government regulation; patent and intellectual property matters; competition; as well as other risks described in Part I, Item 1A, “Risk Factors,” in our Annual Report on Form 10-K filed on March 23, 2022, subsequent Reports on Form 10-Q, and our other filings we make with the SEC. We expressly disclaim any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in our expectations or any changes in events, conditions or circumstances on which any such statement is based, except as required by law, and we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995. Company Contact:Jaclyn JaffeMustang Bio, Inc.(781) 652-4500ir@mustangbio.com Investor Relations Contact:Daniel FerryLifeSci Advisors, LLC(617) 430-7576daniel@lifesciadvisors.com Media Relations Contact:Tony Plohoros6 Degrees(908) 591-2839tplohoros@6degreespr.com MUSTANG BIO, INC.Balance Sheets (Unaudited) (in thousands, except share and per share amounts) September 30, December 31, 2022 2021 ASSETS Current Assets: Cash and cash equivalents $91,364 $109,618 Other receivables - related party 33 50 Prepaid expenses and other current assets 3,050 2,038 Total current assets 94,447 111,706 Property, plant and equipment, net 8,950 9,025 Fixed assets - construction in process 1,095 2,027 Restricted cash 1,000 1,000 Other assets 320 362 Operating lease right-of-use asset, net 3,024 1,050 Total Assets $108,836 $125,170 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities: Accounts payable and accrued expenses $12,810 $9,744 Payables and accrued expenses - related party 152 723 Operating lease liabilities - short-term 595 348 Total current liabilities 13,557 10,815 Deferred income 270 270 Note payable, long-term, net 27,293 — Operating lease liabilities - long-term 3,391 1,685 Total Liabilities 44,511 12,770 Stockholders’ Equity Preferred stock ($0.0001 par value), 2,000,000 shares authorized, 250,000 shares of Class A preferred stock issued and outstanding as of September 30, 2022 and December 31, 2021, respectively — — Common stock ($0.0001 par value), 200,000,000 and 150,000,000 shares authorized as of September 30, 2022 and December 31, 2021, respectively Class A common shares, 845,385 shares issued and outstanding as of September 30, 2022 and December 31, 2021, respectively — — Common shares, 106,427,767 and 93,582,991 shares issued and outstanding as of September 30, 2022 and December 31, 2021, respectively 11 9 Common stock issuable, 6,987 and 2,536,607 shares as of September 30, 2022 and December 31, 2021, respectively 4 4,329 Additional paid-in capital 374,045 359,906 Accumulated deficit (309,735) (251,844)Total Stockholders’ Equity 64,325 112,400 Total Liabilities and Stockholders’ Equity $108,836 $125,170 MUSTANG BIO, INC.Statements of Operations (Unaudited) (in thousands, except share and per share amounts) For the three months ended September 30, For the nine months ended September 30, 2022 2021 2022 2021Operating expenses: Research and development $15,419 $14,083 $46,872 $36,603 Research and development – licenses acquired 40 630 40 1,630 General and administrative 3,389 2,364 9,815 8,371 Total operating expenses 18,848 17,077 56,727 46,604 Loss from operations (18,848) (17,077) (56,727) (46,604) Other income (expense) Grant income 669 — 669 — Interest income 216 75 366 294 Interest expense (1,034) (3) (2,199) (11)Total other income (expense) (149) 72 (1,164) 283 Net Loss $(18,997) $(17,005) $(57,891) $(46,321) Net loss per common share outstanding, basic and diluted $(0.18) $(0.19) $(0.57) $(0.54) Weighted average number of common shares outstanding, basic and diluted 105,917,723 91,136,969 102,289,247 86,487,092

WORCESTER, Mass., Aug. 11, 2022 (GLOBE NEWSWIRE) -- Mustang Bio, Inc. (“Mustang”) (NASDAQ: MBIO), a clinical-stage biopharmaceutical company focused on translating today’s medical breakthroughs in cell and gene therapies into potential cures for hematologic cancers, solid tumors and rare genetic diseases, today announced financial results and recent corporate highlights for the second quarter ended June 30, 2022. Manuel Litchman, M.D., President and Chief Executive Officer of Mustang, said, “We are very pleased with the significant clinical and regulatory milestones achieved in the first half of 2022 for our portfolio of cell and gene therapies. Interim Phase 1/2 data on MB-106, our CD20-targeted, autologous CAR T cell therapy for patients with relapsed or refractory B-cell non-Hodgkin lymphomas (“B-NHLs”) and chronic lymphocytic leukemia (“CLL”), were presented at several prestigious medical meetings. MB-106 continues to demonstrate high efficacy and a favorable safety profile across all patients with a wide range of hematologic malignancies including follicular lymphoma (“FL”), CLL, diffuse large B-cell lymphoma (“DLBCL”) and Waldenstrom macroglobulinemia (“WM”), with no cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome greater than grade 2. Additionally, the U.S. Food and Drug Administration (“FDA”) granted Orphan Drug Designation to MB-106 for WM, a rare type of B-NHL. We are excited by the continued progress of MB-106 and anticipate dosing the first patient shortly in a multicenter Phase 1/2 clinical trial evaluating the safety and efficacy of MB-106 for relapsed or refractory B-NHL and CLL under Mustang’s Investigational New Drug application (“IND”). Furthermore, we expect to enroll 3 to 6 patients in this trial by the end of 2022 and to disclose data from both the single-center Fred Hutch trial and the multicenter Mustang trial in the fourth quarter of this year. We also continued to advance our recurrent glioblastoma (“rGBM") clinical program. Data presented at the American Association for Cancer Research (“AACR”) Annual Meeting 2022 support the safety of administering our two clinical candidates, MB-108 (Nationwide Children’s herpes simplex virus type 1 oncolytic virus) and MB‐101 (City of Hope’s IL13Rα2‐targeted CAR T cell therapy), sequentially to optimize treatment in a regimen designated as MB-109, for which we plan to file an IND in 2023.” “Mustang is pleased to be a leader in the development of gene therapy treatments for severe combined immunodeficiency (“SCID”) patients. Interim Phase 1/2 data on treatment with the same lentiviral vector used in MB-107, our ex vivo lentiviral gene therapy for X-linked SCID (“XSCID”) in newly diagnosed infants under the age of two, presented at the American Society of Gene & Cell Therapy (“ASGCT”) 25th Annual Meeting showed all 23 treated patients were alive at 2.6-year median follow-up without evidence of malignant transformation, and the treatment established a stable, functioning immune system in patients. We also announced that the first patient successfully received LV-RAG1 ex vivo lentiviral gene therapy to treat recombinase-activating gene-1 (“RAG1”) SCID (“RAG1-SCID”), in an ongoing Phase 1/2 multicenter clinical trial taking place in Europe. Mustang has exclusively licensed LV-RAG1 for the development of MB-110, a first-in-class ex vivo lentiviral gene therapy for RAG1-SCID. XSCID and RAG1-SCID make up almost 60% of all SCID cases combined. We look forward to the continued advancement of our SCID clinical program, including our anticipated initiation in 2023 under Mustang’s IND of multicenter pivotal Phase 2 trials for both MB-107 in newborn XSCID patients and MB-207 in previously transplanted XSCID patients.” Recent Corporate Highlights: In April 2022, Mustang announced that interim Phase 1/2 clinical trial data on MB-106, a CD20-targeted, autologous CAR T cell therapy for patients with relapsed or refractory B-cell NHL and CLL, were presented at the 2022 Tandem Meetings I Transplantation & Cellular Therapy Meetings of the American Society of Transplantation and Cellular Therapy and Center for International Blood & Marrow Transplant Research. Data demonstrated high efficacy and a favorable safety profile in all patients (n=25). Five dose levels were used during the study, and CRs were observed at all dose levels. Durable responses were observed in a wide range of hematologic malignancies including FL, CLL, DLBCL, and WM. An overall response rate (“ORR”) of 96% and a complete response rate (“CR”) of 72% were observed in all patients across all dose levels. Within the next 60 days, Mustang expects to dose the first patient in a multicenter Phase 1/2 clinical trial evaluating the safety and efficacy of MB-106 for relapsed or refractory B-NHL and CLL, and further expects to enroll 3 to 6 patients in this trial by the end of 2022.Also in April 2022, MB-106 data focused on CLL were presented at the 4th International Workshop on CAR-T and Immunotherapies.Additionally, in April 2022, Mustang announced interim data from two ongoing investigator-sponsored Phase 1 clinical trials evaluating two clinical candidates, MB‐101 (IL13Rα2‐targeted CAR T cell therapy licensed from City of Hope) and MB-108 (herpes simplex virus type 1 oncolytic virus licensed from Nationwide Children’s Hospital) for the treatment of recurrent glioblastoma (“rGBM”). The data were from a late-breaking poster presented at the AACR Annual Meeting 2022. Preclinical data also presented support the safety of administering these two therapies sequentially to optimize treatment in a regimen designated as MB-109. Mustang expects to file an IND in 2023 to initiate an MB-109 Phase 1 clinical trial.In May 2022, interim Phase 1/2 data on treatment with the same lentiviral vector used in MB-107, Mustang’s lentiviral gene therapy for XSCID, also known as bubble boy disease, in newly diagnosed infants under the age of two, were presented in an oral presentation during the Clinical Trials Spotlight Symposium at the ASGCT 25th Annual Meeting. The presentation included updated data from a multicenter Phase 1/2 clinical trial for XSCID in newly diagnosed infants under the age of two at St. Jude Children’s Research Hospital, UCSF Benioff Children’s Hospital in San Francisco and Seattle Children’s Hospital. All 23 treated patients were alive at 2.6-year median follow-up without evidence of malignant transformation.In June 2022, MB-106 CD20-targeted autologous CAR T cell therapy data were presented in an oral session at the European Hematology Association 2022 Hybrid Congress. Mazyar Shadman, M.D., M.P.H., Associate Professor and physician at Fred Hutchinson Cancer Center and University of Washington presented updated interim data from the ongoing Phase 1/2 clinical trial for B-NHL and CLL. Data presented included a 94% ORR and 78% CR in 18 patients with FL. Overall, for the 26 patients treated on the trial, there was a 96% ORR and 73% CR, including complete responses in both DLBCL patients, both WM patients, and both patients previously treated with CD19-targeted CAR-T therapy (1 DLBCL patient and 1 FL patient).Also in June 2022, the FDA granted Orphan Drug Designation to MB-106 CD20-targeted autologous CAR T cell therapy for the treatment of WM, a rare type of B-NHL.In July 2022, Mustang announced that the first patient successfully received LV-RAG1 ex vivo lentiviral gene therapy to treat RAG1-SCID, in an ongoing Phase 1/2 multicenter clinical trial taking place in Europe. LV-RAG1 is exclusively licensed by Mustang for the development of MB-110, a first-in-class ex vivo lentiviral gene therapy for the treatment of RAG1-SCID.In 2023, Mustang expects to enroll the first patient in a pivotal multicenter Phase 2 clinical trial under Mustang’s IND to evaluate MB-107, a lentiviral gene therapy for the treatment of infants under the age of two with XSCID.Mustang filed an IND application in December 2021 for its pivotal multicenter Phase 2 clinical trial of MB-207, a lentiviral gene therapy for the treatment of patients with XSCID who have been previously treated with hematopoietic stem cell transplantation (“HSCT”) and for whom re-treatment is indicated. The trial is currently on hold pending CMC clearance from the FDA and, based on feedback from the Agency, Mustang expects to enroll the first patient in a pivotal multicenter Phase 2 clinical trial in 2023. Financial Results: As of June 30, 2022, Mustang’s cash and cash equivalents and restricted cash totaled $108.4 million, compared to $123.2 million at March 31, 2022 and $110.6 million as of December 31, 2021, a decrease of $14.8 million for the quarter and a decrease of $2.2 million year-to-date.Research and development expenses were $15.2 million for the second quarter of 2022, compared to $11.9 million for the second quarter of 2021. Non-cash, stock-based expenses included in research and development were $0.4 million for the second quarter of 2022, compared to $0.3 million for the second quarter of 2021.General and administrative expenses were $3.1 million for the second quarter of 2022, compared to $2.5 million for the second quarter of 2021. Non-cash, stock-based expenses included in general and administrative expenses were $0.2 million for the second quarter of 2022, compared to $0.2 million for the second quarter of 2021.Net loss attributable to common stockholders was $19.1 million, or $0.19 per share, for the second quarter of 2022, compared to a net loss attributable to common stockholders of $14.4 million, or $0.16 per share, for the second quarter of 2021. About Mustang BioMustang Bio, Inc. is a clinical-stage biopharmaceutical company focused on translating today’s medical breakthroughs in cell and gene therapies into potential cures for hematologic cancers, solid tumors and rare genetic diseases. Mustang aims to acquire rights to these technologies by licensing or otherwise acquiring an ownership interest, to fund research and development, and to outlicense or bring the technologies to market. Mustang has partnered with top medical institutions to advance the development of CAR-T therapies across multiple cancers, as well as lentiviral gene therapies for severe combined immunodeficiency. Mustang’s common stock is registered under the Securities Exchange Act of 1934, as amended, and Mustang files periodic reports with the U.S. Securities and Exchange Commission (“SEC”). Mustang was founded by Fortress Biotech, Inc. (NASDAQ: FBIO). For more information, visit www.mustangbio.com. Forward‐Looking StatementsThis press release contains “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. Such statements, which are often indicated by terms such as “anticipate,” “believe,” “could,” “estimate,” “expect,” “goal,” “intend,” “look forward to,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “will,” “would” and similar expressions, include, but are not limited to, any statements relating to our growth strategy and product development programs, including the timing of and our ability to make regulatory filings such as INDs and other applications and to obtain regulatory approvals for our product candidates, statements concerning the potential of therapies and product candidates, and any other statements that are not historical facts. Forward-looking statements are based on management’s current expectations and are subject to risks and uncertainties that could negatively affect our business, operating results, financial condition and stock value. Factors that could cause actual results to differ materially from those currently anticipated include: risks relating to our growth strategy; our ability to obtain, perform under, and maintain financing and strategic agreements and relationships; risks relating to the results of research and development activities; risks relating to the timing of starting and completing clinical trials; uncertainties relating to preclinical and clinical testing; our dependence on third-party suppliers; our ability to attract, integrate and retain key personnel; the early stage of products under development; our need for substantial additional funds; government regulation; patent and intellectual property matters; competition; as well as other risks described in Part I, Item 1A, “Risk Factors,” in our Annual Report on Form 10-K filed on March 23, 2022, subsequent Reports on Form 10-Q, and our other filings we make with the SEC. We expressly disclaim any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in our expectations or any changes in events, conditions or circumstances on which any such statement is based, except as required by law, and we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995. Company Contacts:Jaclyn Jaffe and Bill BegienMustang Bio, Inc.(781) 652-4500ir@mustangbio.com Investor Relations Contact:Daniel FerryLifeSci Advisors, LLC(617) 430-7576daniel@lifesciadvisors.com Media Relations Contact:Tony Plohoros6 Degrees(908) 591-2839tplohoros@6degreespr.com MUSTANG BIO, INC.Balance Sheets (Unaudited) (in thousands, except share and per share amounts) June 30, December 31, 2022 2021 ASSETS Current Assets: Cash and cash equivalents $107,369 $109,618 Other receivables - related party 33 50 Prepaid expenses and other current assets 1,974 2,038 Total current assets 109,376 111,706 Property, plant and equipment, net 8,663 9,025 Fixed assets - construction in process 1,537 2,027 Restricted cash 1,000 1,000 Other assets 359 362 Operating lease right-of-use asset, net 970 1,050 Total Assets $ 121,905 $ 125,170 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities: Accounts payable and accrued expenses $10,165 $9,744 Payables and accrued expenses - related party 448 723 Operating lease liabilities - short-term 368 348 Total current liabilities 10,981 10,815 Deferred income 270 270 Note payable, long-term, net 27,150 — Operating lease liabilities - long-term 1,496 1,685 Total Liabilities 39,897 12,770 Commitments and Contingencies Stockholders’ Equity Preferred stock ($0.0001 par value), 2,000,000 shares authorized, 250,000 shares of Class A preferred stock issued and outstanding as of June 30, 2022 and December 31, 2021, respectively — — Common stock ($0.0001 par value), 200,000,000 and 150,000,000 shares authorized as of June 30, 2022 and December 31, 2021, respectively Class A common shares, 845,385 shares issued and outstanding as of June 30, 2022 and December 31, 2021, respectively — — Common shares, 104,511,195 and 93,582,991 shares issued and outstanding as of June 30, 2022 and December 31, 2021, respectively 10 9 Common stock issuable, 41,652 and 2,536,607 shares as of June 30, 2022 and December 31, 2021, respectively 28 4,329 Additional paid-in capital 372,708 359,906 Accumulated deficit (290,738) (251,844)Total Stockholders’ Equity 82,008 112,400 Total Liabilities and Stockholders’ Equity $ 121,905 $ 125,170 MUSTANG BIO, INC.Statements of Operations (Unaudited) (in thousands, except share and per share amounts) For the three months ended June 30, For the six months ended June 30, 2022 2021 2022 2021 Operating expenses: Research and development $15,164 $10,902 $31,453 $22,520 Research and development – licenses acquired — 1,000 — 1,000 General and administrative 3,077 2,538 6,426 6,007 Total operating expenses 18,241 14,440 37,879 29,527 Loss from operations (18,241) (14,440) (37,879) (29,527) Other income (expense) Interest income 77 85 150 219 Interest expense (935) (4) (1,165) (8)Total other income (expense) (858) 81 (1,015) 211 Net Loss $ (19,099) $ (14,359) $ (38,894) $ (29,316) Net loss per common share outstanding, basic and diluted $(0.19) $(0.16) $(0.39) $(0.35) Weighted average number of common shares outstanding, basic and diluted 102,947,158 87,561,764 100,444,938 84,033,508