# EDGAR Filing Document

**Accession Number:** 0001680048
**File Stem:** 0001104659-25-124189
**Filing Date:** 2025-12
**Character Count:** 13731
**Document Hash:** f134ec8e0cfab7deedf60360acd2cb6e
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-25-124189.hdr.sgml**: 20251223

**ACCESSION NUMBER**: 0001104659-25-124189

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 14

**CONFORMED PERIOD OF REPORT**: 20251217

**ITEM INFORMATION**: Submission of Matters to a Vote of Security Holders

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20251223

**DATE AS OF CHANGE**: 20251223

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** MUSTANG BIO, INC.
- **CENTRAL INDEX KEY:** 0001680048
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 473828760
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-38191
- **FILM NUMBER:** 251600499

**BUSINESS ADDRESS:**
- **STREET 1:** 95 SAWYER RD
- **STREET 2:** SUITE 110
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02453
- **BUSINESS PHONE:** 7816524500

**MAIL ADDRESS:**
- **STREET 1:** 95 SAWYER RD
- **STREET 2:** SUITE 110
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02453

?xml version='1.0' encoding='ASCII'? Mustang Bio, Inc._December 17, 2025

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**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**WASHINGTON, D.C. 20549**

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**FORM 8-K**

**CURRENT REPORT**

**Pursuant to Section 13 or 15(d) of the**

**Securities Exchange Act of 1934**

Date of report (Date of earliest event reported): **December 17, 2025**

**Mustang Bio, Inc.**

(Exact Name of Registrant as Specified in Charter)

---

| | | |
|:---|:---|:---|
| **Delaware** | **001-38191** | **47-3828760** |
| (State or Other Jurisdiction <br>of Incorporation) | (Commission File Number) | (IRS Employer<br>Identification No.) |

---

**95 Sawyer Road, Suite 110**

**Waltham, Massachusetts 02453**

(Address of Principal Executive Offices)

**(781) 652-4500**

(Registrant's telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

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| | | |
|:---|:---|:---|
| Title of each class | Trading Symbol(s) | Name of each exchange on which registered |
| **Common Stock, par value $0.0001 per share** | **MBIO** | **Nasdaq Capital Market** |

---

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

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**Item 5.07** **Submission of Matters to a Vote of Security Holders.**

Mustang Bio, Inc. ("Mustang" of the "Company") held its 2025 Annual Meeting of stockholders (the "2025 Annual Meeting") on December 22, 2025 by means of an online virtual meeting platform at 9:00 a.m. Eastern Time. At the 2025 Annual Meeting, the following four proposals were approved: (i) the election of seven directors to hold office until the 2026 annual meeting of stockholders; (ii) the ratification of the appointment of KPMG LLP as Mustang's independent registered public accounting firm for the year ending December 31, 2025; (iii) the amendment to the Company's 2019 Employee Stock Purchase Plan (the "ESPP") to increase the number of shares issuable by 250,000 shares and increase the number of shares subject to a Purchase Right thereunder to 10,000; and (iv) the amendment to the Company's 2016 Incentive Plan (the "EIP") to increase the number of shares issuable by Mustang by 2,500,000 shares. The four proposals are described in detail in the Company's 2025 Definitive Proxy Statement on Schedule 14A.

As of November 18, 2025, the record date for the determination of the shareholders entitled to notice of, and to vote at, the 2025 Annual Meeting, 6,453,701 shares of the Company's Common Stock were outstanding and eligible to vote with an aggregate of 6,453,701 votes; 845,385 shares of the Company's Class A Common Stock were outstanding and eligible to vote with an aggregate of 1,127 votes; and 250,000 shares of the Company's Class A Preferred Stock were outstanding and eligible to vote with an aggregate of 7,100,677 votes, as determined in accordance with Section 3.1.3 of the Company's Amended and Restated Articles of Incorporation. Approximately 58% of all votes were represented at the 2025 Annual Meeting, constituting a quorum.

**Proposal 1**

The votes with respect to the election of seven directors to hold office until the 2026 annual meeting were as follows:

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| | | | |
|:---|:---|:---|:---|
| **Director** | **For** | **Withheld** | **Broker Non-Votes** |
| Michael S. Weiss | 7768359 | 99071 | 0 |
| Manuel Litchman, M.D. | 7712919 | 154511 | 0 |
| Lindsay A. Rosenwald, M.D. | 7740512 | 126918 | 0 |
| Neil Herskowitz | 7724042 | 143388 | 0 |
| David Jin | 7769563 | 97867 | 0 |
| Adam Chill | 7795608 | 71822 | 0 |
| Michael Zelefsky, M.D. | 7795753 | 71677 | 0 |

---

**Proposal 2**

The votes with respect to the ratification of KPMG LLP as Mustang's independent registered accounting firm for the year ending December 31, 2025, were as follows:

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| | | |
|:---|:---|:---|
| **Total Votes For** | **Total Votes Against** | **Abstentions** |
| 7844671 | 9814 | 12945 |

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**Proposal 3**

The votes with respect to the approval of the amendment to the Company's ESPP were as follows:

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| | | |
|:---|:---|:---|
| **Total Votes For** | **Total Votes Against** | **Abstentions** |
| 7815313 | 49380 | 2737 |

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**Proposal 4**

The votes with respect to the approval of an amendment to the Company's EIP were as follows:

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| | | |
|:---|:---|:---|
| **Total Votes For** | **Total Votes Against** | **Abstentions** |
| 7664161 | 198991 | 4278 |

---

**Item 8.01** **Other Events**

As previously disclosed, Mustang Bio, Inc. (the "Company") previously entered into that certain License Agreement with Fred Hutchinson Cancer Center ("Fred Hutch"), dated as of May 17, 2017 (as amended, the "CD20 License Agreement"), under which the Company developed its CD20 CAR-T program. On December 17, 2025, the Company and Fred Hutch entered into a Termination and Release Agreement, pursuant to which: (i) the Company and Fred Hutch agreed to terminate the CD20 License Agreement; (ii) the Company agreed to pay Fred Hutch $730,000 as consideration for extinguishment of approximately $1.4 million in outstanding payables owing to Fred Hutch; and (iii) the parties agreed that, in the event that Fred Hutch, during the three-year period following execution of the Termination and Release Agreement, grants any third party a license under the CD20 patents or other intellectual property that had been licensed to the Company under the CD20 License Agreement, then Fred Hutch will pay to the Company at least 10% of all consideration received by Fred Hutch from such third party under such licensing arrangement (with an additional obligation to negotiate in good faith for a potentially greater percentage share).

**Item 9.01** **Financial Statements and Exhibits**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) Exhibits

The following exhibits are filed as part of this report:

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| | |
|:---|:---|
| **Exhibit No.** | **Description** |
| 10.1 | [Amendment No. 3 to the Mustang Bio, Inc. 2019 Employee Stock Purchase Plan](tmb-20251217xex10d1.htm) |
| 10.2 | [Fourth Amendment to the Mustang Bio, Inc., 2016 Incentive Plan](tmb-20251217xex10d2.htm) |
| 104 | Cover Page Interactive Data File (formatted as Inline XBRL) |

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#### SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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| | | |
|:---|:---|:---|
|  | **Mustang Bio, Inc.** | **Mustang Bio, Inc.** |
| Date: December 23, 2025 |  |  |
|  | By: | /s/ Manuel Litchman, M.D. |
|  |  | Manuel Litchman, M.D. |
|  |  | President, Chief Executive Officer and Interim Chief Financial Officer |

---

## Exhibit 10.1

**Exhibit 10.1**

**AMENDMENT NO. 3 TO THE<br>MUSTANG BIO, INC.<br>2019 EMPLOYEE STOCK PURCHASE PLAN**

This amendment (the "Amendment") to the Mustang Bio, Inc. 2019 Employee Stock Purchase Plan, as amended (the "Plan"), is hereby adopted this 22 day of December, 2025, by the Board of Directors (the "Board") of Mustang Bio, Inc. (the "Company").

**WITNESETH**:

**WHEREAS**, the Company adopted the Plan for the purposes set forth therein; and

**WHEREAS**, pursuant to Section 21 of the Plan, the Board has the right to amend the Plan with respect to certain matters, provided that any material increase in the number of Shares available under the Plan shall be subject to stockholder approval; and

**WHEREAS**, the Board has approved and authorized this Amendment to the Plan and has recommended that the stockholders of the Company approve this Amendment;

**NOW, THEREFORE, BE IT RESOLVED**, that the Plan is hereby amended, subject to and effective as of the date of stockholder approval hereof, in the following particulars:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. Section 3 of the Plan is hereby amended by increasing the share references in such section from 9,333 to 259,333, so that such section reads in its entirety as follows:

"3. Share Reserve. The maximum number of shares which may be issued under the Plan shall be 259,333 shares of Mustang's authorized but unissued common stock, $0.0001 par value (the "Shares"). In the event that any Purchase Right for any reason expires or is canceled or terminated, the Shares allocable to the unexercised portion of such Purchase Right may again be subjected to a Purchase Right."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. Section 7(b) is hereby amended by increasing the Purchase Right from 100 to 10,000 so that such section reads in its entirety as follows:

"(b) 10,000 Shares."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3. Except as specifically set forth herein, the terms of the Plan shall be and remain unchanged, and the Plan as amended shall remain in full force and effect.

The foregoing is hereby acknowledged as being the Amendment to the Plan, as adopted by the Board on November 17, 2025, and approved by the Company's stockholders on December 22, 2025.

**MUSTANG BIO, INC.**

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| | |
|:---|:---|
| By: | <u>/s/ Manuel Litchman, M.D.</u>  |

---

Name: Manuel Litchman, M.D. <br>Title: President, Chief Executive Officer and Interim Chief Financial Officer

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## Exhibit 10.2

**Exhibit 10.2**

**FOURTH AMENDMENT TO THE MUSTANG BIO, INC.**

**2016 INCENTIVE PLAN**

This Fourth Amendment to the Mustang Bio, Inc. 2016 Incentive Plan (the "Plan"), is hereby adopted on this 22 day of December, 2025, by the Board of Directors (the "Board") of Mustang Bio, Inc. (the "Company").

#### WITNESETH:
**WHEREAS**, the Company adopted the Plan for the purposes set forth therein; and

**WHEREAS**, pursuant to Section 15.1 of the Plan, the Board has the right to amend the Plan with respect to certain matters, provided that any material increase in the number of Shares available under the Plan shall be subject to stockholder approval; and

**WHEREAS**, the Board has approved and authorized this Fourth Amendment to the Plan and has recommended that the stockholders of the Company approve this Fourth Amendment;

**NOW, THEREFORE, BE IT RESOLVED**, that the Plan is hereby amended, subject to and effective as of the date of stockholder approval hereof, in the following particulars:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. Section 5.1 of the Plan is hereby amended by increasing the share references in such section from 14,666 to 2,514,666, so that such section reads in its entirety as follows:

"5.1. NUMBER OF SHARES. Subject to adjustment as provided in Sections 5.2 and Section 14.1, the aggregate number of Shares reserved and available for issuance pursuant to Awards granted under the Plan shall be 2,514,666. The maximum number of Shares that may be issued upon exercise of Incentive Stock Options granted under the Plan shall be 2,514,666. The maximum aggregate number of Shares associated with any Award granted under the Plan in any calendar year to any one Non-Employee Director shall be 100,000 Shares."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. Except as specifically set forth herein, the terms of the Plan shall be and remain unchanged, and the Plan as amended shall remain in full force and effect.

The foregoing is hereby acknowledged as being the Fourth Amendment to the Plan, as adopted by the Board on November 17, 2025, and approved by the Company's stockholders on December 22, 2025.

**MUSTANG BIO, INC.**

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| | |
|:---|:---|
| By: | <u>/s/ Manuel Litchman, M.D.</u>  |

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Name: Manuel Litchman, M.D. <br>Title: President, Chief Executive Officer and Interim Chief Financial Officer

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