10-K/A

Viskase Holdings, Inc. (ENZN)

10-K/A 2025-04-28 For: 2024-12-31
View Original
Added on April 06, 2026

Table of Contents ​

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K/A

(Amendment No. 1)

ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the Fiscal Year Ended December 31, 2024

OR

TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from         to

Commission file number: 000-12957

Enzon Pharmaceuticals, Inc.

(Exact name of registrant as specified in its charter)

Delaware **** 22-2372868
(State or other jurisdiction of incorporation or organization) (I.R.S. Employer Identification No.)
20 Commerce Drive (Suite 135), **** Cranford , New Jersey 07016
(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: (732) 980-4500

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

Title of Each Class Trading Symbol(s) Name of Each Exchange on Which Registered
None N/A N/A

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

Common Stock, $0.01 par value

Series A-1 Junior Participating Preferred Stock Purchase Rights

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. ☐  Yes     ⌧  No

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Exchange Act. ☐  Yes     ⌧  No

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. ⌧  Yes     ☐  No

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). ⌧  Yes     ☐  No

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act:

Large accelerated filer ☐ Accelerated filer ☐
Non-accelerated filer ☒ Smaller reporting company ☒
Emerging growth company ☐

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. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). ☐  Yes     ☒  No

The aggregate market value of the Common Stock, $0.01 par value per share (“the Common Stock”), held by non-affiliates of the registrant was approximately $6,814,434 as of June 28, 2024, based upon the closing sale price quoted on the OTCQX market of the OTC Markets Group, Inc. of $0.18 per share reported for such date. Shares of Common Stock held by each executive officer and director and certain beneficial owners of 10% or more of the Common Stock of the registrant as of June 30, 2024 have been excluded in that such shares may be deemed to be owned by affiliates. This determination of affiliate status is not necessarily a conclusive determination for other purposes.

There were 74,214,603 shares of Common Stock issued and outstanding as of April 28, 2025.

DOCUMENTS INCORPORATED BY REFERENCE

None.

Auditor Name Auditor Firm ID Auditor Location
EisnerAmper LLP 274 Philadelphia, Pennsylvania

Table of Contents ENZON PHARMACEUTICALS, INC.

2024 Annual Report on Form 10-K/A

(Amendment No. 1)

Table of Contents

Page
Explanatory Note 3
PART III 4
Item 10. Directors, Executive Officers and Corporate Governance 4
Item 11. Executive Compensation 7
Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters 9
Item 13. Certain Relationships and Related Transactions, and Director Independence 10
Item 14. Principal Accountant Fees and Services 11
PART IV 12
Item 15. Exhibits and Financial Statement Schedules 12

​ 2

Table of Contents EXPLANATORY NOTE

Enzon Pharmaceuticals, Inc. (the “Company,” “we,” “us,” or “our”) is filing this Amendment No. 1 on Form 10-K/A (this “Amendment No. 1”) to amend our Annual Report on Form 10-K for the year ended December 31, 2024, originally filed with the Securities and Exchange Commission (the “SEC”) on February 21, 2025 (our “Annual Report”). We are amending our Annual Report to include the information required by Items 10 through 14 of Part III of Form 10-K (the “Part III Information”). The Part III Information, pursuant to General Instruction G(3), is required to be filed no later than 120 days after our fiscal year-end.

Pursuant to the rules of the SEC, Part IV, Item 15 has also been amended to contain the currently dated certification from the Company’s principal executive officer who is also the Company’s principal financial officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. The certification of the Company’s principal executive officer and principal financial officer are attached to this Amendment No. 1 as Exhibit 31.1. Because no financial statements have been included in this Amendment No. 1 and this Amendment No. 1 does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4 and 5 of the certification have been omitted. Additionally, we are not including a currently dated certification under Section 906 of the Sarbanes-Oxley Act of 2002 as no financial statements are being filed with this Amendment No. 1. Furthermore, Item 15 is also being amended to include the Company’s trading policy as Exhibit 19.1.

This Amendment No. 1 does not amend any other information set forth in our Annual Report and we have not updated disclosures included therein to reflect any subsequent events. This Amendment No. 1 should be read in conjunction with our Annual Report and with our filings with the SEC subsequent to our Annual Report.

​ 3

Table of Contents PART III.

Item 10. Directors, Executive Officers and Corporate Governance

The following table sets forth certain information concerning our executive officers and directors.

Name **** Age **** Director/Officer Since **** Position with Our Company ****
Randolph C. Read 72 2020 Chairman of the Board
Jordan Bleznick 69 2020 Director
Jaffery (Jay) A. Firestone 68 2022 Director
Stephen T. Wills 68 2025 Director
Richard L. Feinstein 81 2013 Chief Executive Officer, Chief Financial Officer, and Secretary

Directors

Randolph C. Read – Mr. Read has been a director of our Company since August 2020, and since that time has served as our Chairman of the Board and Chairman of the Finance and Audit Committee. Mr. Read has been President and Chief Executive Officer of Nevada Strategic Credit Investments, LLC for more than five years and has been the President and Chief Executive Officer of International Capital Markets Group, Inc. for more than five years. Mr. Read has served since November 2018 as an independent manager/director and Chairman of the Board of Managers of New York REIT Liquidating, LLC, a successor to New York REIT, Inc., a publicly traded (NYSE) real estate investment trust, where Mr. Read served as an independent director from December 2014 to November 2018, including as Chairman of its Board of Directors from June 2015 to November 2018. Mr. Read has served as an independent director of SandRidge Energy, Inc. (NYSE), an oil and natural gas exploration and production company, since June 2018. Mr. Read previously served as an independent director of Luby’s Inc. from August 2019 to August 2021. Mr. Read has previously served as President of a variety of other companies and has previously served on a number of public and private company boards. Mr. Read is admitted as a Certified Public Accountant and has an M.B.A. in Finance from the Wharton Graduate School of the University of Pennsylvania and a B.S. from Tulane University.

Mr. Read’s qualifications to serve as a director of our Company include his significant business experience as a director and an executive officer of entities in a variety of industries, as well as capital markets, governance, and operations experience, in addition to his knowledge, financial expertise and leadership qualities and roles, including his experience as Chairman of our board of directors.

Jordan Bleznick  – Mr. Bleznick has been a director of our Company since August 2020. From April 2002 through his retirement in April 2023, Mr. Bleznick was the Vice President/Taxes of Starfire Holding Corporation, a privately-held holding company controlled by Carl C. Icahn. From April 2002 through his retirement in April 2023, he was the Chief Tax Counsel for various affiliates of Mr. Icahn. In March 2023, Mr. Bleznick was appointed as a director and Chairman of the Board, and member of the compensation committee, of the general partner of CVR Partners, LP, a nitrogen fertilizer company controlled by Mr. Icahn. From April 2021 until April 2023, Mr. Bleznick was a director of various other affiliates of Mr. Icahn, including American Entertainment Properties Corp., which is the primary operating subsidiary of Icahn Enterprises L.P. From March 2000 through March 2002, Mr. Bleznick was a partner in the New York City office of the law firm of DLA Piper. From March 1984 until February 2000, he was an associate and then a partner at the New York City law firm of Gordon Altman Weitzen Shalov and Wein. Mr. Bleznick received a B.A. in Economics from the University of Cincinnati, a J.D. from The Ohio State University College of Law and a L.L.M. in Taxation from the New York University School of Law.

Mr. Bleznick’s qualifications to serve as a director of our Company include his expertise in tax law and his involvement with other public companies owned by Carl C. Icahn and affiliated entities.

Jaffery (Jay) A. Firestone – Mr. Firestone has been a director of our Company since June 2022. He has served as Chairman and Chief Executive Officer at Prodigy Pictures Inc., a producer of film, television and cross-platform media, since 2006. Previously, Mr. Firestone established Fireworks Entertainment in 1996 to produce, distribute and finance television programs and feature films. In 1998, Fireworks Entertainment was acquired by CanWest Global Communications Corporation and Mr. Firestone was named chairman and chief executive officer and oversaw the company’s Los Angeles and London based television operations as well as its 4

Table of Contents Los Angeles feature film division, Fireworks Pictures. In addition, Mr. Firestone oversaw the company’s interest in New York based IDP Distribution, an independent distribution and marketing company formed by Fireworks Entertainment in 2000 as a joint venture with Samuel Goldwyn Films and Stratosphere Entertainment. Mr. Firestone has served on the board of directors for the Academy of Canadian Cinema and Television and the Academy of Television Arts and Sciences International Council in Los Angeles. Mr. Firestone has led two initial public offerings. Mr. Firestone has been a director of CVR Energy, Inc. (NYSE), a diversified holding company primarily engaged in the renewables, petroleum refining and marketing business, since April 2020 and SandRidge Energy, Inc. (NYSE) since May 2021, and previously served as a director of Voltari Corporation, a commercial real estate company, from July 2011 through September 2019. Mr. Firestone obtained a degree in commerce from McMasters University.

Mr. Firestone’s qualifications to serve as a director of our Company include his extensive experience in dealing with financial reporting and his past service on other public company boards.

Stephen T. Wills, CPA, MST – Mr. Wills was appointed as a director of the Company in January 2025. He currently serves as Chief Financial Officer, Treasurer, Secretary (since 1997), and Chief Operating Officer (since 2011), of Palatin Technologies, Inc. a biopharmaceutical company developing medicines based on molecules that modulate the activity of the melanocortin receptor system. Mr. Wills has served on the board of directors of MediWound Ltd. (Nasdaq: MDWD), a biopharmaceutical company focused on treatment in the fields of severe burns, chronic and other hard to heal wounds, since April 2017, and as chairperson from October 2017 until August 2022, and is the chair of the audit committee and a member of the compensation committee. Mr. Wills served on the board of directors of Gamida Cell Ltd., a cellular and immune therapeutics company, and as chair of the audit committee and a member of the compensation committee, from March 2019 through June 2024, when Gamida was acquired by Highbridge Capital Management. Mr. Wills served as the Chief Financial Officer of Cactus Acquisition Corp, a Special Purpose Acquisition Company, from November 2021 until March 2024, when a new sponsor acquired majority ownership. Mr. Wills served on the board of directors of Amryt Pharma, a biopharmaceutical company focused on developing and delivering treatments to help improve the lives of patients with rare and orphan diseases, and as chair of the audit committee and a member of the compensation committee, from September 2019 through April 2023, when Amryt was acquired by Chiesi Farmaceutici. Mr. Wills, a certified public accountant, earned his Bachelor of Science in accounting from West Chester University, and a Master of Science in taxation from Temple University.

Mr. Wills’ qualifications to serve as a director of our Company include his significant business experience as a director and an executive officer.

Management

Richard L. Feinstein – Mr. Feinstein has served as our Chief Executive Officer, Chief Financial Officer, and Secretary since February 2021, having previously served as Vice President-Finance and Chief Financial Officer since March 2016. Prior to that, Mr. Feinstein served as our Vice President – Finance and Principal Financial Officer since December 2013. Mr. Feinstein is a retired partner of KPMG LLP and currently a private consultant providing management and financial advice to clients in a variety of industries. From 2015 to 2019, he provided financial consulting services to General Cannabis Corp., now known as Trees Corporation, a public company. During July 2016, he provided consulting services to Hamaspik, Inc. From September 2010 to July 2013, as a consultant, he was the Chief Financial Officer of Ameritrans Capital Corporation. From April 2004 to December 2004, Mr. Feinstein, as a consultant, served as Chief Financial Officer for Image Technology Laboratories, Inc., a developer and provider of radiological imaging, archiving and communications systems. From December 1997 to October 2002, Mr. Feinstein was Senior Vice-President and Chief Financial Officer for The Major Automotive Companies, Inc., formerly a diversified holding company, but now engaged solely in retail automotive dealership operations. Mr. Feinstein has served on boards of both publicly- held and not-for-profit enterprises. Mr. Feinstein previously served as a board member and chair of the audit committee of MKTG, Inc.; a board member and chief financial officer of the not-for-profit USA Fitness Corps; a board member and chair of the audit committee of EDGAR Online, Inc.; a board member and chair of the finance committee of the New York Road Runners; and a member of the executive committee of the Association for a Better New York. Mr. Feinstein, a certified public accountant, received a BBA degree from Pace University. Mr. Feinstein also served in the United States Marine Corps. 5

Table of Contents Director Independence

Although our Common Stock is no longer listed on The Nasdaq Stock Market (“Nasdaq”), our Board continues to use the definition of independence set forth in the listing standards of Nasdaq in evaluating the independence of our directors. Our Board has determined that each of Messrs. Read, Bleznick, Firestone and Wills is independent as defined by the listing standards of Nasdaq.

Meetings and Attendance

Our Board held ten meetings during fiscal year 2024. Each director who served on the Board during fiscal year 2024 attended at least 75% of the total number of meetings held during fiscal year 2024 by our Board and committees of our Board of which such director was a member (during the period that the director served).

We do not have a policy requiring our directors to attend our annual stockholders’ meetings. All of our then-serving directors attended the 2024 annual meeting either in person or virtually.

Board Leadership Structure

Our Board is led by a Chairperson appointed by our Board annually. The Chairperson leads our Board in its role of providing advice to, and overseeing the performance of, our Chief Executive Officer. Randolph C. Read currently serves as the Chairman of the Board, and Richard L. Feinstein currently serves as our Chief Executive Officer. Our Board does not have a formal policy with respect to the separation of the positions of Chairperson and Chief Executive Officer. However, our Board believes that separating these positions allows the Chief Executive Officer to focus on day-to-day operations, while allowing the Chairperson to lead our Board in its primary role of review and oversight of management.

Hedging or Pledging of Company Stock

Our Company maintains a policy prohibiting our employees, officers and directors from engaging in hedging or pledging transactions involving Company stock or holding Company stock in a margin account.

Communications with Directors

Stockholders may communicate directly with our directors. All communications should be sent in care of our Secretary at our address and should prominently indicate on the outside of the envelope that it is intended for our Board or for a specific director. If no director is specified, the communication will be forwarded to the entire Board.

Standing Committees of our Board

During 2024, the only standing committee of the Board was the Finance and Audit Committee.

Finance and Audit Committee

During 2024, our Finance and Audit Committee was comprised of Mr. Read, who has also served as Chairman of the committee since August 2020, and Mr. Firestone. Our Finance and Audit Committee held four meetings during fiscal year 2024. Mr. Wills was appointed to the Finance and Audit Committee in January 2025.

In evaluating the composition of our Finance and Audit Committee, our Board has determined that each current member is, and during 2024 all members were, independent as defined by the listing standards of Nasdaq and Rule 10A-3 under the Exchange Act. Our Board has determined that Mr. Read satisfies the definition of “audit committee financial expert” within the meaning of Item 407(d)(5) of Regulation S-K.

The primary purpose of the Finance and Audit Committee is to monitor the integrity of our Company’s financial reporting process and financial statements, the systems of internal controls and controls over financial reporting, our Company’s compliance with legal and regulatory requirements, and the performance and independence of our Company’s independent registered public accounting firm. The Finance and Audit Committee is responsible for discussing with management the adequacy of our Company’s 6

Table of Contents internal controls and the financial reporting process. The Finance and Audit Committee also is responsible for discussing these matters with our Company’s independent registered public accounting firm. In addition, the Finance and Audit Committee is responsible for reviewing our financial statements and discussing them with management and our Company’s independent registered public accounting firm before those financial statements are filed with the SEC. The charter of the Finance and Audit Committee may be found on the Corporate Governance page of our website at www.enzon.com.

Other Board Committees

Currently, we do not have other standing committees such as a nominating committee or a compensation committee, and the Board is of the view that it is not necessary to have such committees at this time because the Board is currently composed of only four members, all of whom are independent as defined by the listing standards of Nasdaq. Our Board directly performs the functions of a nominating committee and oversees the process by which individuals may be nominated to our Board. The Board also directly performs the functions of a compensation committee and oversees the process by which our named executive officer, who is a consultant, and directors are compensated. We currently have no employees.

Our Board’s Role in Risk Oversight

We, like other companies, face a variety of risks, including operational, financial, regulatory, legal, and information technology and cybersecurity. While our Board oversees risk management, our executive officer is responsible for day-to-day risk management and provides updates to our Board as appropriate regarding risk management activities. Risk oversight is a significant component in all major Board decisions and the evaluation of risk is an important element in our Board’s decision-making process. Our Board believes that the processes it has established for overseeing risk would be effective under a variety of leadership frameworks and therefore do not materially affect its choice of leadership structure as described above.

Code of Conduct

Our Board has adopted a Code of Conduct and Corporate Values (the “Code of Conduct”) that is applicable to all of our directors and executive officers. Any material changes made to the Code of Conduct or any waivers granted to any of our directors and executive officers will be publicly disclosed on our website at www.enzon.com within four business days of such material change or waiver. A copy of our Code of Conduct is available on the Corporate Governance page of our website at www.enzon.com.

Insider Trading Policy

The Company maintains an insider trading policy. The Company believes its insider trading policy is reasonably designed to promote compliance with applicable insider trading laws, rules and regulations. The insider trading policy governs the purchase, sale and/or other dispositions of the Company’s securities and applies to all officers, directors, and employees. The Code of Conduct expands the insider trading policies to partners, including family members, relatives or friends. The Code of Conduct also extends the insider trading policy to temporary insiders, i.e., those individuals who have a special confidential relationship in the conduct of the Company’s affairs and, as a result, are given access to information solely for the Company’s purpose.

Item 11. Executive Compensation

Summary Compensation Table

**** **** **** **** Stock **** Option **** All Other ****
Name and Principal Salary Bonus Awards Awards Compensation Total
Position Year ($) ($) ($) ($) ($)(1) ($)
Richard L. Feinstein<br>Chief Executive Officer, Chief 2024 17,500 209,425 226,925
Financial Officer and Secretary 2023 15,000 209,068 224,068

(1) The amounts in this column reflect fees and expenses related to services rendered during fiscal years 2024 and 2023 on a consulting basis. Mr. Feinstein did not receive a base salary for fiscal year 2024 or 2023.

7

Table of Contents Narrative Disclosure to Summary Compensation Table

Richard L. Feinstein

On February 24, 2022, the Company entered into a revised consulting agreement with Richard L. Feinstein, the Company’s Chief Executive Officer, Chief Financial Officer and Secretary. The agreement provides for Mr. Feinstein’s consulting fee to be set at $200,000 per year and an incentive of up to 25% of the fee at the discretion of our Board based on the Company’s and Mr. Feinstein’s performance. In 2023, the Board agreed to increase Mr. Feinstein’s consulting fee to $210,000.

Outstanding Equity Awards at December 31, 2024

The 2011 Stock Option Plan and Incentive Plan was terminated effective February 24, 2022. As of December 31, 2024, Mr. Feinstein does not hold any outstanding stock options or other equity awards in the company.

Equity Award Timing Procedures

In accordance with Item 402(x) of Regulation S-K under the Securities Act, we are providing information regarding our procedures related to the grant of certain equity awards close in time to the release of material non-public information (“MNPI”). We do not have a formal policy, program or plan that requires us to award equity or equity-based compensation on specific dates. Additionally, our insider trading policy prohibits directors, officers and employees from trading in our common stock while in possession of or on the basis of MNPI about us. We have not timed, and do not plan to time, the disclosure of MNPI for the purpose of affecting the value of executive compensation.

No options were granted to our named executive officer within four business days prior to, or one business day following, the filing or furnishing of a periodic or current report by us that disclosed MNPI during the year ended December 31, 2024.

Potential Payments Upon Termination or Change in Control

Mr. Feinstein is not covered by a severance or change in control agreement and, accordingly, he would not have been entitled to receive any termination or change in control-related payments as of December 31, 2024.

Director Compensation Plan

Currently, each of our directors is compensated in the amount of $36,666 per annum (pro-rated for partial periods of service). The one-fourth of the annual cash compensation is payable quarterly at the end of each quarter.

Total Director Compensation

A summary of compensation paid to each of our directors during fiscal year 2024 is set forth below:

**** Fees Earned **** **** ****
or Paid in Stock Option
Cash Awards Awards Total
Name ($) ($)(1) ($)(2) ($)(3)
Randolph C. Read 36,666 36,666
Jordan Bleznick 36,666 36,666
Jaffery (Jay) A. Firestone 36,666 36,666

(1) As of December 31, 2024, none of the directors listed held any outstanding restricted stock units.
(2) As of December 31, 2024, none of the directors listed held any outstanding stock options.
--- ---
(3) Stephen T. Wills was appointed to the board effective January 7, 2025, and during 2024 did not earn any fees, hold any stock awards or hold any outstanding stock options as of December 31, 2024.
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Table of Contents Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

The following table sets forth certain information as of April 28, 2025 concerning stock ownership of (i) each person known by us to own beneficially more than 5% of our outstanding Common Stock, (ii) each of our directors as of such date, (iii) each of our named executive officers, and (iv) all of our directors and current executive officers as a group. Information set forth in this table as to our directors and current executive officers is based upon information supplied by these individuals. Information in this table as to our greater than 5% stockholders is based solely upon the Schedules 13D or 13G filed by these stockholders with the SEC. Where information is based on a Schedule 13D or 13G, the number of shares owned is as of the date for which information was provided in such schedules.

**** Amount and **** ****
Nature of Percentage of ****
Beneficial Voting Stock ****
Name of Beneficial Owner or Identity of Group(1) Ownership(2) Outstanding(3) ****
Randolph C. Read 200,000 *
Jordan Bleznick 100,000 *
Jaffery A. Firestone
Richard L. Feinstein
Carl C. Icahn and affiliated entities 36,056,636 (4) 48.6 %
Jonathan Couchman and affiliated entities 7,743,954 (5) 10.4 %
Stephen T. Wills(6)
All Directors and Current Executive Officers as a group (5 persons) 300,000 *
* Less than one percent
--- ---
(1) The address for each of the named executive officers and directors listed in this table is c/o Enzon Pharmaceuticals, Inc., 20 Commerce Drive, Suite 135, Cranford, New Jersey, 07016.
--- ---
(2) Beneficial ownership is determined in accordance with the rules of the SEC that deem shares to be beneficially owned by any person who has or shares voting or investment power with respect to such shares. Unless otherwise indicated below, the persons and entities named in the table have sole voting and sole investment power with respect to all the shares beneficially owned, subject to community property laws where applicable.
--- ---
(3) Based on 74,214,603 shares of Common Stock, which were issued and outstanding as of the close of business on April 28, 2025. Each share of Common Stock is entitled to one vote. The percentage of voting stock outstanding for each person set forth in the table is calculated by dividing (i) the number of shares of Common Stock deemed to be beneficially held by such person as of April 28, 2025 by (ii) the sum of (A) the number of shares of Common Stock outstanding as of April 28, 2025, plus (B) the number of shares of Common Stock subject to stock options, if any, held by such person that were exercisable as of April 28, 2025 or will become exercisable within 60 days after April 28, 2025.
--- ---
(4) Information concerning stock ownership was obtained from Amendment No. 15 to the Schedule 13D filed with the SEC on December 19, 2024 by Carl C. Icahn and various entities affiliated with him. The address for Carl C. Icahn and entities affiliated with him is 16690 Collins Avenue, Suite PH-1, Sunny Isles Beach, FL 33160. Mr. Icahn was reported to share voting and dispositive power over all 36,056,636 shares of Common Stock with entities affiliated with him. In addition, Mr. Icahn, through entities affiliated with him, also reported ownership of 39,277 shares of the Company’s Series C Non-Convertible Redeemable Preferred Stock, which represents approximately 98% of all outstanding shares of Series C Preferred Stock.
--- ---
(5) Information concerning stock ownership was obtained from Amendment No. 2 to the Schedule 13D filed with the SEC on September 17, 2020 and the Form 4 filed August 17, 2021 by Jonathan Couchman (“Mr. Couchman”), Couchman Family Fund (the “Foundation”), Xstelos Corp. (“Xstelos”) and Myrexis, Inc. (“Myrexis”). Mr. Couchman reported sole voting and dispositive power over 4,717,666 shares and shared voting and dispositive power over the shares directly held by the Foundation, Xstelos and Myrexis. The Form 4 reported that the Foundation directly held 350,000 shares, Xstelos directly held 2,043,024 shares, and Myrexis directly held 633,264 shares, and each reported shared voting and dispositive power over such shares. The principal business address for Mr. Couchman, the Foundation and Myrexis is c/o Couchman Management LLC, 600 Fifth Avenue, 2nd Floor, New York, NY 10020. The principal business address for Xstelos is 1105 North Market Street, Suite 1300, Wilmington, DE 19801.
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9

Table of Contents

(6) Mr. Wills was appointed to the Board effective January 7, 2025.

Securities Authorized for Issuance under Equity Compensation Plans

We currently have no equity compensation plans, or outstanding awards pursuant to any previously adopted equity compensation plans, and the Board does not consider granting any equity awards.

Item 13. Certain Relationships and Related Transactions, and Director Independence

Our Board has adopted a formal written policy that we will not enter into any “related party transaction” (defined consistent with Item 404 of Regulation S-K under the Exchange Act) unless the Finance and Audit Committee or a comparable committee of disinterested directors approves such transaction. No member of the Finance and Audit Committee or comparable committee shall participate in the review or approval of any related party transaction or any material amendment thereto where that member is a related party in that transaction. In reviewing and approving any related party transaction or any material amendment thereto, the Finance and Audit Committee or comparable committee shall satisfy itself that it has been fully informed as to the related party’s relationship and interest and as to the material facts of the proposed related party transaction or material amendment, and shall determine that the related party transaction or material amendment thereto is fair to our Company. As previously disclosed, in connection with a potential transaction between us and a company controlled by our significant stockholder, in January 2025, our Board of Directors formed a special committee of independent directors (the “Special Committee”) and delegated full authority to the Special Committee to consider, negotiate and vote upon any such potential transaction, as well as any strategic alternatives that may be put forth with regard to such potential transaction. The Special Committee is comprised of Messrs. Read and Wills. The Special Committee continues to consider any such potential transaction and no assurances can be given that a definitive agreement will be reached or that any such potential transaction will be consummated.

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Table of Contents Item 14. Principal Accountant Fees and Services

Audit Fees, Audit-Related Fees, Tax Fees and All Other Fees

The following table sets forth the aggregate fees paid or payable for services provided to us by EisnerAmper LLP for professional services rendered for the fiscal years ended December 31, 2024 and 2023. The Finance and Audit Committee considered whether the provision of these services by EisnerAmper LLP was compatible with maintaining the firm’s independence and concluded that EisnerAmper LLP was “independent.”

EisnerAmper LLP
**** Fiscal Year **** Fiscal Year
Ended Ended
December 31, 2024 December 31, 2023
Audit Fees(1) $ 119,700 $ 115,500
Audit-Related Fees
Tax Fees(2) $ 9,450 $ 8,925
All Other Fees
Total $ 129,150 $ 124,425
(1) For fiscal years 2024 and 2023, “Audit Fees” paid or payable to EisnerAmper LLP related to services in connection with the audit of our annual consolidated financial statements, review of quarterly financial statements, issuance of consents, review of documents filed with the SEC and accounting consultations.
--- ---
(2) For fiscal years 2024 and 2023, “Tax Fees” paid or payable to EisnerAmper LLP related to tax preparation services and tax consulting services.
--- ---

​ 11

Table of Contents PART IV

Item 15. Exhibits and Financial Statement Schedules

(a)(1), (a)(2) and (c). The response to this portion of Item 15 is submitted as a separate section of this report commencing on page F-1.

(a)(3) and (b). Exhibits (numbered in accordance with Item 601 of Regulation S-K).

Exhibit Reference
Number Description No.
3.1 Amended and Restated Certificate of Incorporation dated May 18, 2006, together with that Certificate of Amendment to the Amended and Restated Certificate of Incorporation dated July 13, 2010 (1)
3.2 Second Amended and Restated By-Laws effective March 11, 2011, as amended by Amendment No. 1 to the Second Amended and Restated By-Laws effective February 15, 2013 (2)
3.3 Certificate of Designation of Series A-1 Junior Participating Preferred Stock of Enzon Pharmaceuticals, Inc. filed with the Secretary of State of the State of Delaware on August 14, 2020 (4)
3.4 Certificate of Designation of Series C Non-Convertible Redeemable Preferred Stock of Enzon Pharmaceuticals, Inc., filed with the Secretary of State of the State of Delaware on September 21, 2020 (5)
3.5 First Amendment to the Second Amended and Restated By-Laws, effective February 24, 2022 (9)
4.1 Description of Enzon Pharmaceuticals, Inc.’s Registered Securities (12)
4.2 Section 382 Rights Agreement, dated as of August 14, 2020, by and between Enzon Pharmaceuticals, Inc. and Continental Stock Transfer & Trust Company, which includes the Form of Certificate of Designation as Exhibit A, Form of Rights Certificate as Exhibit B and the Form of Summary of Rights as Exhibit C (4)
4.3 First Amendment to the Section 382 Rights Agreement, dated as of June 4, 2021 and effective as of June 2, 2021, by and between Enzon Pharmaceuticals, Inc. and Continental Stock Transfer & Trust Company. (6)
4.4 Second Amendment to the Section 382 Rights Agreement, dated as of May 16, 2024, by and between Enzon Pharmaceuticals, Inc., and Continental Stock Transfer & Trust Company (11)
4.5 Third Amendment to the Section 382 Rights Agreement, dated as of March 31, 2025, by and between Enzon Pharmaceuticals, Inc., and Continental Stock Transfer & Trust Company (13)
10.1 Development, License and Supply Agreement between Enzon, Inc. (now known as Enzon Pharmaceuticals, Inc.) and Schering Corporation dated November 14, 1990, as amended* (3)
10.3 Amended and Restated Exclusive IP Marketing Agreement, dated as of June 28, 2004, by and between Micromet AG and Enzon Pharmaceuticals, Inc. (7)
10.4 Letter Agreement, dated January 30, 2019, between Servier IP UK Limited and Enzon Pharmaceuticals, Inc. (7)
10.5 Investment Agreement, dated as of September 1, 2020, by and between Enzon Pharmaceuticals, Inc. and Icahn Capital LP (8)
10.6 Independent Contractor Agreement, effective as of February 24, 2022, between Enzon Pharmaceuticals, Inc. and Richard L. Feinstein ** (9)
10.7 Form of Indemnification Agreement for members of the Board of Directors ** (10)
19.1 Insider Trading Policy +
21.1 Subsidiaries of Registrant (12)
23.1 Consent of EisnerAmper LLP (12)
31.1 Certification of Principal Executive Officer and Principal Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 +
32.1 Certification of Principal Executive Officer and Principal Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002*** (12)
101.INS Inline XBRL Instance Document (12)
101.SCH Inline XBRL Taxonomy Extension Schema Document (12)
101.CAL Inline XBRL Calculation Linkbase Document (12)
101.LAB Inline XBRL Labels Linkbase Document (12)
101.PRE Inline XBRL Presentation Linkbase Document (12)
101.DEF Inline XBRL Definition Linkbase Document (12)
104 Cover Page Interactive Data File (formatted as Inline XBRL and contained in the Interactive Data Files submitted as Exhibit 101) (12)
+ Filed herewith
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* Portions of this exhibit have been redacted and filed separately with the SEC pursuant to a confidential treatment request.

12

Table of Contents

** Management contracts or compensatory plans and arrangements required to be filed pursuant to Item 601(b)(10)(ii)(A) or (iii) of Regulation S-K.
*** In accordance with Item 601(b)(32)(ii) of Regulation S-K and SEC Release Nos. 33-8238 and 34-47986, Final Rule: Management’s Reports on Internal Control Over Financial Reporting and Certification of Disclosure in Exchange Act Periodic Reports, the certification furnished in Exhibit 32.1 hereto is deemed to accompany this Annual Report on Form 10-K and will not be deemed “filed” for purposes of Section 18 of the Exchange Act. Such certification will not be deemed to be incorporated by reference into any filing under the Securities Act or the Exchange Act, except to the extent that the registrant specifically incorporates it by reference.
--- ---

Referenced exhibit was previously filed with the SEC as an exhibit to the Company’s filing indicated below and is incorporated herein by reference to that filing:

(1) Quarterly Report on Form 10-Q for the quarter ended June 30, 2010 filed August 9, 2010
(2) Annual Report on Form 10-K for the year ended December 31, 2012 filed March 18, 2013
--- ---
(3) Annual Report on Form 10-K for the fiscal year ended June 30, 2002 filed on September 26, 2002
--- ---
(4) Current Report on Form 8-K filed August 14, 2020
--- ---
(5) Current Report on Form 8-K filed September 23, 2020
--- ---
(6) Current Report on Form 8-K filed June 8, 2021
--- ---
(7) Annual Report on Form 10-K for the fiscal year ended December 31, 2018 filed on February 21, 2019
--- ---
(8) Current Report on Form 8-K filed September 1, 2020
--- ---
(9) Annual Report on Form 10-K for the fiscal year ended December 31, 2021 filed on February 25, 2022
--- ---
(10) Quarterly report on Form 10-Q for the quarter ended March 31, 2022 filed April 26, 2022
--- ---
(11) Current Report on Form 8-K filed on May 22, 2024
--- ---
(12) Annual Report on Form 10-K for the fiscal year ended December 31, 2024 filed on February 21, 2025
--- ---
(13) Current Report on Form 8-K filed on April 1, 2025
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​ 13

Table of Contents SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this Amendment No. 1 to Annual Report on Form 10-K to be signed on its behalf by the undersigned, thereunto duly authorized.

ENZON PHARMACEUTICALS, INC.
(Registrant)
Dated: April 28, 2025 /s/ Richard L. Feinstein
Richard L. Feinstein
Chief Executive Officer, Chief Financial Officer and Secretary
(Principal Executive Officer and Principal Financial Officer)

Pursuant to the requirements of the Securities Exchange Act of 1934, this Amendment No. 1 to Annual Report on Form 10-K has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

Name Title Date
/s/ Richard L. Feinstein Chief Executive Officer, Chief Financial Officer and Secretary April 28, 2025
Richard L. Feinstein (Principal Executive Officer and Principal Financial Officer)
/s/ Randolph C. Read Director (Chairman of the Board) April 28, 2025
Randolph C. Read
/s/ Jordan Bleznick Director April 28, 2025
Jordan Bleznick<br><br>​
/s/ Jaffrey (Jay) A. Firestone Director April 28, 2025
Jaffrey (Jay) A. Firestone
/s/ Stephen T. Wills Director April 28, 2025
Stephen T. Wills

​ 14

Exhibit 19.1

Graphic Corporate Policy Manual Page No.: 1 of 9
Title: Insider Trading Effective Date: July 21, 2006, revised September 27, 2012 and April 25, 2025
Policy No.: CPM-CP-102.03 Applies to: All employees, officers and Board<br>members of Enzon Pharmaceuticals

1.INTRODUCTION AND PURPOSE:

1.1.Since the common stock of Enzon Pharmaceuticals, Inc. (“Enzon” or the “Company”) is publicly traded, the Company, its directors, officers, and employees, including employees of any subsidiary or affiliated company of Enzon, are subject to “insider trading” laws. Enzon and its subsidiaries are collectively referred to as “Enzon” or the “Company”. Such laws prohibit individuals with Material Non-Public Information (as defined herein) with respect to a company from making decisions to purchase, sell, give away or otherwise trade the company’s securities or the securities of certain other companies or to provide that information to others outside the company or from giving such information to another person (commonly known as “tipping”). In addition, such laws require companies and supervisory personnel to affirmatively supervise the actions of employees. This Policy applies to all transactions in (i) Enzon’s common stock, options to purchase common stock and any other securities Enzon may issue from time to time, such as preferred stock, warrants and convertible debt securities, as well as derivative securities relating to Enzon’s stock, whether or not issued by Enzon, such as exchange traded options and (ii) the securities of certain other companies, including common stock, options and other securities issued by those companies as well as derivative securities relating to any of those companies' securities, where the person trading used information obtained while working for the Company.

The purpose of this Policy is to:

require that all Enzon Personnel be attentive to and comply with applicable laws and regulations relating to insider trading; and
maintain the integrity and reputation of Enzon and its directors, officers and employees.
--- ---

​ 1

Graphic Corporate Policy Manual Page No.: 2 of 9
Title: Insider Trading Effective Date: July 21, 2006, revised September 27, 2012 and April 25, 2025
Policy No.: CPM-CP-102.03 Applies to: All employees, officers and Board<br>members of Enzon Pharmaceuticals

2.SCOPE :

This Policy applies to all directors, officers and employees of Enzon (collectively, “Enzon Personnel”). Additionally, Enzon Personnel are responsible for compliance with this policy by their spouses, family members and others living in their households, business partners and any other people or entities who might reasonably be deemed to have a relationship (legal, personal or otherwise) meriting coverage including, without limitation, any investment fund, trust, retirement plan, partnership, corporation or other entity over which you have the ability to influence or direct investment decisions concerning securities; provided, however, that this Policy shall not apply to any such entity that engages in the investment of securities in the ordinary course of its business (e.g., an investment fund or partnership) if such entity has established its own insider trading controls and procedures in compliance with applicable securities laws. Therefore, all references in this Policy to Enzon Personnel shall also apply to such people. Enzon Personnel are also expected to advise all consultants and contractors engaged by the Company of this Policy and advise such persons that they are expected to adhere to this Policy while engaged by the Company as if employed by the Company.

Directors, officers and employees of the Company should carefully read this Policy and are required to sign the attached statement acknowledging that they have read and understood the Policy.

The Company has appointed the Chief Executive Officer as the compliance officer (the "Compliance Officer") for this Policy.

3.POLICY:

3.1. Prohibition Against Trading on Material Non-Public Information: ****

No Enzon Personnel may purchase or sell, or offer to purchase or sell, any Company security, whether or not issued by the Company at any time when in possession of Material Non-Public Information. For purposes of this Policy, the terms “sale”, “transactions”, “trade” and “trading”, as they apply to the Company’s securities, shall include gifts of Enzon securities by Enzon Personnel. If Material Non-Public Information relating to the Company has not been available to the public for at least one (1) full trading day, Enzon Personnel are prohibited from trading in Company securities or directly or indirectly disclosing the Material Non-Public Information to any other persons. For example, if the Company makes an announcement of a material event after the start of trading on a Monday, Enzon Personnel would not be able to trade Enzon securities until Wednesday (assuming Tuesday is a trading day). In

​ 2

Graphic Corporate Policy Manual Page No.: 3 of 9
Title: Insider Trading Effective Date: July 21, 2006, revised September 27, 2012 and April 25, 2025
Policy No.: CPM-CP-102.03 Applies to: All employees, officers and Board<br>members of Enzon Pharmaceuticals

order for the information to be deemed to be available to the public, such information must be known through an official announcement, not through rumors or an unofficial announcement.

Material Non-Public Information: Material Non-Public Information is any information about a company or its business not generally available to the public which a reasonable investor would want to know before making an investment decision. In other words, any information that could reasonably be expected to affect the market price of a security is material information. The Securities and Exchange Commission (the “SEC”) and the courts have generally given a broad interpretation to what is considered “Material Information.”

Common examples of Material Information include:

developments with any of the Company’s products
results of clinical trials
--- ---
patent related developments or milestones
--- ---
significant litigation or litigation developments
--- ---
information about a transaction that will significantly affect the financial condition of a company
--- ---
projections of future earnings or losses
--- ---
news of a pending or proposed merger, acquisition or tender offer
--- ---
news of a significant regulatory approval or rejection
--- ---
changes in management
--- ---
major new products
--- ---
impending bankruptcy or financial liquidity problems
--- ---
the gain or loss of a substantial contract
--- ---
important financing transactions
--- ---

The foregoing list is not exhaustive — any information that might be considered important to an investor may be considered “material.” If you have any questions concerning any situation or transaction that you believe might violate this Policy, you should promptly bring it to the attention of the Company’s Compliance Officer.

​ 3

Graphic Corporate Policy Manual Page No.: 4 of 9
Title: Insider Trading Effective Date: July 21, 2006, revised September 27, 2012 and April 25, 2025
Policy No.: CPM-CP-102.03 Applies to: All employees, officers and Board<br>members of Enzon Pharmaceuticals

Transactions that may be necessary or justifiable for independent reasons (such as the need to raise money for an emergency expenditure) are no exception. Even the appearance of an improper transaction must be avoided to preserve the Company’s reputation for adhering to the highest standards of conduct.

3.2. Trading Blackout Period: ****

To avoid the appearance of trading on Material Non-Public Information relating to earnings, no director, officer or employee of the Company may purchase or sell securities of the Company during the period commencing on the day that is ten (10) calendar days immediately prior to the last day of each calendar quarter and ending at the commencement of trading on Nasdaq on the second (2^nd^) full trading day after the Company makes its public quarterly earnings announcement. For example, for the quarter ended December 31, this trading prohibition would commence on December 21. If the Company made its quarterly earnings announcement after the start of trading on February 19, the trading prohibition would end as of the commencement of trading on Nasdaq on February 21, assuming that February 20 and February 21 were both trading days. It is important to note that compliance with this blackout period trading prohibition will not relieve liability for trading on or tipping Material Non-Public Information at other times.

The Blackout Period also applies to the discretionary use of outstanding Company securities to constitute part or all of the exercise price of an option, any sale of stock as part of a broker-assisted cashless exercise of an option, or any other market sale for the purpose of generating the cash needed to pay the exercise price of an option.

3.3. Transactions by Family Members; Transactions After Your Employment Ends: ****

The very same restrictions apply to family members and any other individuals living in the household of a director, officer or employee. Directors, officers and employees are expected to be responsible for the compliance of their immediate family and personal household.

If your employment with the Company ends at a time when you have or think you may have Material Non-Public Information about the Company or its business partners, the prohibition on trading on such information continues until such information is absorbed

​ 4

Graphic Corporate Policy Manual Page No.: 5 of 9
Title: Insider Trading Effective Date: July 21, 2006, revised September 27, 2012 and April 25, 2025
Policy No.: CPM-CP-102.03 Applies to: All employees, officers and Board<br>members of Enzon Pharmaceuticals

by the market following public announcement or until such time as the information is no longer material.

3.4. Transactions Under Company Plans

This Policy does not apply to purchases of the Company’s common stock under the Company’s employee stock purchase plan resulting from your regular payroll deductions under the plan pursuant to the election you made at the time of your enrollment in the plan. This Policy does apply, however, to (a) your election to participate in the plan for any enrollment period, (b) any election by you to increase or decrease the rate of your payroll deductions and (c) your sales of the Company’s common stock purchased pursuant to the plan.

3.5. No Tipping Information to Others:

Enzon Personnel must not pass Material Non-Public Information on to others (commonly known as “tipping”). Penalties under federal securities laws apply whether or not the tipper derives a benefit from a tippee’s actions. In fact, the SEC has imposed substantial penalties on tippers even though they did not profit from their tippee’s trading.

3.6. No Trading in Securities of Certain Other Companies: ****

If any Enzon Personnel have obtained any Material Non-Public Information relating to another company with which the Company has done or is doing business, such personnel may not buy or sell securities of such other company or engage in any other action to take advantage of, or pass on to others, that information. This includes Material Non-Public Information relating to the existence of a transaction or possible transaction with another company.

3.7. Receive Clearance Prior to Any Transaction in Securities: ****

To avoid any inadvertent violation of trading prohibitions and to enable directors and officers to file their Form 4 reports under Section 16(a) of the Exchange Act on a timely basis, no officer, director or employee of Enzon may purchase or sell securities of the Company unless the officer, director or employee submits a request to transact in company stock form which is approved in advance by the Company’s Compliance Officer.

​ 5

Graphic Corporate Policy Manual Page No.: 6 of 9
Title: Insider Trading Effective Date: July 21, 2006, revised September 27, 2012 and April 25, 2025
Policy No.: CPM-CP-102.03 Applies to: All employees, officers and Board<br>members of Enzon Pharmaceuticals

Once the transaction is cleared, it must be completed within three (3) trading days of approval.

An officer, director or employee must confirm to the Compliance Officer that such transaction was completed no later than the close of business on the date such transaction is completed and shall provide the Compliance Officer with all of the information required to complete a Form 4 reporting such transaction (e.g. the date of the transaction, whether the transaction was an acquisition or disposition, the number of securities involved in the transaction, the price or prices at which the securities were acquired or disposed of, the amount of such securities beneficially owned after the transaction, the nature of the ownership).

3.8. Rule 10b5-1 Arrangements for Selling Company Securities:

Rule 10b5-1 under the Securities Exchange Act of 1934 creates the presumption that a person aware of Material Non-Public Information has “used” that information in trading, subject to designated affirmative defenses aimed at showing that the information was not a factor in the trading decision. These affirmative defenses to the SEC’s awareness-equals-use presumption in Rule 10b5-1 are exclusive and rather narrow. Under Rule 10b5-1, a person found to be “aware” of Material Non-Public Information at the time of a trade must prove that before becoming aware of the information, he or she had (1) entered into a binding contract to make such trade, (2) instructed another person to make the trade for his or her account, or (3) adopted a written plan for trading pursuant to which such trade was made. Such contract, instruction or plan must have either: (a) specified the amount to be purchased or sold, the price (which may be a particular dollar price or the market price on a particular date or a limit price) and the date on which the securities were to be purchased or sold (which may be any date during the period a limit order is in effect), (b) included a written formula or algorithm or computer program for determining amount, price and date, or (c) permitted the trading person to exercise no influence over how, when or whether to effect purchases or sales.

Rule 10b5-1 will protect officers and directors from insider trading liability under Rule 10b-5 for transactions under a previously established contract, plan or instruction. Purchases and sales of securities of the Company by officers and directors pursuant to arrangements that satisfy the requirements of Rule 10b5-1 and that are approved by the

​ 6

Graphic Corporate Policy Manual Page No.: 7 of 9
Title: Insider Trading Effective Date: July 21, 2006, revised September 27, 2012 and April 25, 2025
Policy No.: CPM-CP-102.03 Applies to: All employees, officers and Board<br>members of Enzon Pharmaceuticals

Compliance Officer before they are implemented will be exempt from the restrictions of this Policy.

3.9. Legal Consequences: ****

A person who violates insider trading laws by engaging in transactions in a company's securities when he or she has Material Non-Public Information can be sentenced to a substantial jail term and required to pay a criminal penalty of several times the amount of profits gained or losses avoided. In addition, a person who tips others may also be liable for transactions by the tippees to whom he or she has disclosed Material Non-Public Information. Tippers can be subject to the same penalties and sanctions as the tippees, and the SEC has imposed large penalties even when the tipper did not profit from the transaction. The SEC can also seek substantial civil penalties from any person who, at the time of an insider trading violation, "directly or indirectly controlled the person who committed such violation," which would apply to the Company and/or management and supervisory personnel. These control persons may be held liable for up to the greater of $2,559,636 or three times the amount of the profits gained or losses avoided. Even for violations that result in a small or no profit, the SEC can seek penalties from a company and/or its management and supervisory personnel as control persons.

3.10. Company Sanctions: ****

In addition to the legal consequences associated with violations of “insider trading” laws, Enzon Personnel who fail to comply with this Policy can be subject to sanctions imposed directly by the Company, including dismissal for cause.

3.11. Short-Swing Profits for Directors and Officers: ****

Under federal law, “short-swing” profits belong to and are recoverable by the Company. The Company cannot waive its right to recover short-swing profits; if the Company fails or refuses to collect the profits, a shareholder may commence a lawsuit for collection on behalf of the Company. This federal law applies regardless of whether the director or officer was actually in possession of inside information. Lack of intent to trade on inside information is similarly irrelevant.

Short-swing profits include any “profit” resulting from any combination of purchase and sale or sale and purchase of Company securities, including derivative securities, within six-months of each other. The highest sale price of any securities sold during the six month period will be matched against the lowest purchase price of any securities purchased to determine if a short-swing profit exists. The order in which the purchase

​ 7

Graphic Corporate Policy Manual Page No.: 8 of 9
Title: Insider Trading Effective Date: July 21, 2006, revised September 27, 2012 and April 25, 2025
Policy No.: CPM-CP-102.03 Applies to: All employees, officers and Board<br>members of Enzon Pharmaceuticals

and sale occurred and the fact that they may have involved different shares in the Company are both irrelevant to whether a “profit” exists.

3.12. Short Sales: ****

Federal law prohibits directors and officers of the Company from making “short” sales of Company securities. A short sale is the sale of securities where the Company securities are not actually owned and where delivery on the sale is made with borrowed or subsequently purchased securities. It is unlawful and improper for a director or officer to sell Company securities which he or she does not own.

**4.**COMMUNICATION AND TRAINING: ****

This Policy shall be circulated upon its adoption to all employees, officers and directors. It shall also be provided to all new employees of the Company. All employees will be required to acknowledge in writing their receipt and understanding of this Policy. The Chief Executive Officer shall conduct (or cause to be conducted) appropriate communication and training (both initial and periodic) for employees to ensure that they are apprised of the requirements of this Policy.

​ 8

Graphic Corporate Policy Manual Page No.: 9 of 9
Title: Insider Trading Effective Date: July 21, 2006, revised September 27, 2012 and April 25, 2025
Policy No.: CPM-CP-102.03 Applies to: All employees, officers and Board<br>members of Enzon Pharmaceuticals

ENZON PHARMACEUTICALS, INC.

INSIDER TRADING POLICY ACKNOWLEDGEMENT

TO: Chief Executive Officer
FROM:
Print Name
Position (within Enzon or its subsidiaries or affiliated companies)

This is to acknowledge that I have received, read and understand the Company’s Insider Trading Policy. I agree to comply fully with all of its terms.

Signature
Date

PLEASE SIGN, DATE, AND RETURN THIS ACKNOWLEDGEMENT TO:

20 COMMERCE DRIVE, SUITE 135

CRANFORD, NJ, 07016

Attention: Chief Executive Officer 9

Exhibit 31.1

CERTIFICATIONS

I, Richard L. Feinstein, certify that:

  1. I have reviewed this Amendment No. 1 to the Annual Report on Form 10-K of Enzon Pharmaceuticals, Inc.;

  1. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report.

Date: April 28, 2025
/s/ Richard L. Feinstein
Richard L. Feinstein
Chief Executive Officer, Chief Financial Officer, and Secretary
(Principal Executive Officer and Principal Financial Officer)