# EDGAR Filing Document

**Accession Number:** 0000727510
**File Stem:** 0001104659-25-061414
**Filing Date:** 2025-6
**Character Count:** 17211
**Document Hash:** 00e4741d4281ee72cd2e459ba42b484e
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-25-061414.hdr.sgml**: 20250623

**ACCESSION NUMBER**: 0001104659-25-061414

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20250623

**DATE AS OF CHANGE**: 20250623

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** ENZON PHARMACEUTICALS, INC.
- **CENTRAL INDEX KEY:** 0000727510
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 222372868
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-35587
- **FILM NUMBER:** 251063030

**BUSINESS ADDRESS:**
- **STREET 1:** 20 COMMERCE DRIVE, SUITE 135
- **CITY:** CRANFORD
- **STATE:** NJ
- **ZIP:** 07016
- **BUSINESS PHONE:** 732-980-4500

**MAIL ADDRESS:**
- **STREET 1:** 20 COMMERCE DRIVE, SUITE 135
- **CITY:** CRANFORD
- **STATE:** NJ
- **ZIP:** 07016

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ENZON PHARMACEUTICALS INC
- **DATE OF NAME CHANGE:** 20060324

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ENZON PHARMACEUTICALS  INC
- **DATE OF NAME CHANGE:** 20021211

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ENZON PHARMACEUTICAL  INC
- **DATE OF NAME CHANGE:** 20021210
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** ICAHN CARL C
- **CENTRAL INDEX KEY:** 0000921669
- **STANDARD INDUSTRIAL CLASSIFICATION:** UNKNOWN SIC - 0000 [0000]
- **ORGANIZATION NAME:** CF
- **EIN:** 000000000
- **STATE OF INCORPORATION:** FL
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**BUSINESS ADDRESS:**
- **STREET 1:** C/O ICAHN ENTERPRISES L.P.
- **STREET 2:** 16690 COLLINS AVE., PH-1
- **CITY:** SUNNY ISLES BEACH
- **STATE:** FL
- **ZIP:** 33160
- **BUSINESS PHONE:** 305-422-4145

**MAIL ADDRESS:**
- **STREET 1:** C/O ICAHN ENTERPRISES L.P.
- **STREET 2:** 16690 COLLINS AVE., PH-1
- **CITY:** SUNNY ISLES BEACH
- **STATE:** FL
- **ZIP:** 33160

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ICAHN CARL C ET AL
- **DATE OF NAME CHANGE:** 19950612

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 16)**

**Enzon Pharmaceuticals, Inc.**

*(Name of Issuer)*

**Common Stock, par value $0.01 per share**

*(Title of Class of Securities)*

**293904108**

*(CUSIP Number)*

**Jesse Lynn, Esq.**<br>Icahn Capital LP, 16690 Collins Avenue<br>Suite PH-1<br>Sunny Isles Beach FL 33160<br>305-442-4000

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**06/20/2025**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **293904108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**CARL C ICAHN** | Name of reporting person<br>**CARL C ICAHN** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[x] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[x] | |
| 6 | Citizenship or place of organization<br>**X1** | Citizenship or place of organization<br>**X1** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**36056636.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**36056636.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**36056636.00** | Aggregate amount beneficially owned by each reporting person<br>**36056636.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**48.6%** | Percent of class represented by amount in Row (11)<br>**48.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Comment for Reporting Person:** The Reporting Person may also be deemed to beneficially own shares of Preferred Stock. See Items 4 and 5.

| **CUSIP No.** | **293904108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**ICAHN ENTERPRISES HOLDINGS L.P.** | Name of reporting person<br>**ICAHN ENTERPRISES HOLDINGS L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[x] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[x] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**36056636.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**36056636.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**36056636.00** | Aggregate amount beneficially owned by each reporting person<br>**36056636.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**48.6%** | Percent of class represented by amount in Row (11)<br>**48.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

**Comment for Reporting Person:** The Reporting Person may also be deemed to beneficially own shares of Preferred Stock. See Items 4 and 5.

| **CUSIP No.** | **293904108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**ICAHN ENTERPRISES G.P. INC.** | Name of reporting person<br>**ICAHN ENTERPRISES G.P. INC.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[x] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[x] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**36056636.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**36056636.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**36056636.00** | Aggregate amount beneficially owned by each reporting person<br>**36056636.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**48.6%** | Percent of class represented by amount in Row (11)<br>**48.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** The Reporting Person may also be deemed to beneficially own shares of Preferred Stock. See Items 4 and 5.

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock, par value $0.01 per share

**(b) Name of Issuer:**
Enzon Pharmaceuticals, Inc.

**(c) Address of Issuer's Principal Executive Offices:**
20 Commerce Drive, Suite 135, Cranford, NJ, 07016

This statement constitutes Amendment No. 16 to the Schedule 13D relating to the shares of Common Stock, par value $0.01 per share (the "Shares"), issued by Enzon Pharmaceuticals, Inc., a Delaware corporation (the "Issuer"), and amends the Schedule 13D relating to the Shares filed on March 14, 2008 (as previously amended, the "Original 13D"), on behalf of the Reporting Persons (as defined in Item 2 of this Amendment No. 16 to Schedule 13D). Capitalized terms used herein and not otherwise defined have the respective meanings ascribed thereto in the Original 13D.

**Item 4. Purpose of Transaction**

Item 4 of the Original 13D is hereby amended and supplemented as follows:

Agreement and Plan of Merger of the Issuer and Viskase

On June 20, 2025, the Issuer, EPSC Acquisition Corp., a Delaware corporation and a wholly owned subsidiary of the Issuer ("Merger Sub"), and Viskase Companies, Inc., a Delaware corporation ("Viskase"), entered into an Agreement and Plan of Merger (the "Merger Agreement"). Subsidiaries of Icahn Enterprises Holdings currently own approximately 81% of the outstanding shares of Viskase. Upon the terms and subject to the satisfaction or waiver of the conditions described in the Merger Agreement, Merger Sub will be merged with and into Viskase, with Viskase surviving the Merger as a wholly owned subsidiary of the Issuer (the "Merger"). The Merger is intended to qualify as a tax-free reorganization for U.S. federal income tax purposes. Following the consummation of the Merger (the "Closing"), it is anticipated that the combined company will operate under the name "Viskase Holdings, Inc." and will trade on the "OTCQX" tier of the OTC market of the OTC Markets Group, Inc. The Merger Agreement has been unanimously recommended by a Special Committee of the independent directors of the Issuer (the "Enzon Special Committee") and a Special Committee of the independent directors of Viskase and, acting upon such recommendations, has been unanimously approved by the Boards of Directors of each of the Issuer and Viskase.

The Merger Agreement provides, among other things, that on the terms and subject to the conditions set forth therein, at the effective time of the Merger: (i) each share of common stock, par value $0.01 per share, of Viskase (the "Viskase Common Stock") issued and outstanding immediately prior to the Merger (other than shares held by holders that properly exercise dissenters rights, shares held in treasury, and shares held by the Issuer) will be automatically converted into the right to receive the number of Shares equal to the exchange ratio as calculated under the Merger Agreement (the "Merger Consideration"); (ii) all shares of Viskase Common Stock converted into the right to receive the Merger Consideration will automatically be cancelled and will cease to exist as of the effective time of the Merger; and (iii) each share of the Issuer's Series C Non-Convertible Redeemable Preferred Stock, par value $0.01 per share (the "Series C Preferred Stock"), held by affiliates of the Reporting Persons will be exchanged for Shares at a discount to its liquidation value based upon the 20-day volume weighted average price ("VWAP") of the Shares prior to execution of the Merger Agreement; and (iv) pursuant to the terms of an exchange offer to be commenced by the Issuer, each share of Series C Preferred Stock held by non-affiliates of the Reporting Persons will have the right to be exchanged for Shares at its liquidation value based upon the 20-day VWAP of the Shares prior to execution of the Merger Agreement.

Under the exchange ratio formula in the Merger Agreement and assuming that the Series C Preferred Stock is exchanged for Shares in full, upon closing of the Merger, (x) the holders of Shares immediately prior to the closing of the Merger are expected to own approximately 2.06%  of the combined company's common stock, (y) the holders of Series C Preferred Stock, including the Reporting Persons, are expected to own approximately 13.84% of the combined company's common stock and (z) Viskase stockholders are expected to own approximately 84.1% of the combined company's common stock, subject to certain adjustments based upon the number of shares of Series C Preferred Stock exchanged for Shares by non-affiliates of the Reporting Persons and the amount of cash held by the Issuer at the effective time of the Merger, and depending on the liquidation value of the Series C Preferred Stock at the date of closing of the Merger. Upon the Closing, it is anticipated that the Reporting Persons will beneficially own approximately 91% of the combined company.

The Chief Executive Officer of the combined company will be Timothy P. Feast, who is currently the Chief Executive Officer of Viskase. The Board of Directors of the combined company will be selected by the Board of Directors of Viskase and include Jordan Bleznick, a current member of the Issuer's Board of Directors and former employee of Icahn Enterprises L.P.

The Closing is subject to the satisfaction or waiver of certain customary closing conditions.

The foregoing description does not purport to be complete and is qualified in its entirety by reference to the complete text of the Merger Agreement, a copy of which is attached as Exhibit 1 hereto and incorporated herein by reference.

IEH Support Agreement

In connection with the execution and delivery of the Merger Agreement, Icahn Enterprises Holdings  and certain of its affiliates entered into a support agreement (the "IEH Support Agreement") with the Issuer and Viskase, pursuant to which Icahn Enterprises Holdings  and certain of its affiliates agreed (among other things) to, subject to the terms and conditions set forth therein, (i) deliver or cause the delivery of written consents with respect to all of the issued and outstanding shares of Enzon Common Stock held by Icahn Enterprises Holdings and its affiliates approving the Merger and the amendment to the Issuer's  certificate of incorporation, and (ii) immediately prior to the Closing, exchange each issued and outstanding share of the  Series C Preferred Stock held by Icahn Enterprises Holdings and its affiliates for Shares at a discount to its liquidation value based upon the 20-day VWAP of the Shares prior to execution of the Merger Agreement.

The foregoing description does not purport to be complete and is qualified in its entirety by reference to the complete text of the IEH Support Agreement, a copy of which is attached as Exhibit 2 hereto and incorporated herein by reference.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

Item 6 of the Original 13D is hereby amended and supplemented as follows:

The disclosure set forth in Item 4 of this Schedule 13D is incorporated herein by reference.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** CARL C ICAHN

**Signature:** /s/ Carl C. Icahn

**Name/Title:** Carl C. Icahn

**Date:** 06/23/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** ICAHN ENTERPRISES HOLDINGS L.P.

**Signature:** /s/ Ted Papapostolou

**Name/Title:** Ted Papapostolou / Chief Financial Officer

**Date:** 06/23/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** ICAHN ENTERPRISES G.P. INC.

**Signature:** /s/ Ted Papapostolou

**Name/Title:** Ted Papapostolou / Chief Financial Officer

**Date:** 06/23/2025