# EDGAR Filing Document

**Accession Number:** 0000921669
**File Stem:** 0001193125-26-129970
**Filing Date:** 2026-3
**Character Count:** 12389
**Document Hash:** 7ca33416e638a8b0d7498dab48060c16
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-129970.hdr.sgml**: 20260327

**ACCESSION NUMBER**: 0001193125-26-129970

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

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260327

**DATE AS OF CHANGE**: 20260327

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Viskase Holdings, 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:** 26809553

**BUSINESS ADDRESS:**
- **STREET 1:** 333 EAST BUTTERFIELD ROAD, SUITE 400
- **CITY:** LOMBARD
- **STATE:** IL
- **ZIP:** 60148
- **BUSINESS PHONE:** (630) 874-0700

**MAIL ADDRESS:**
- **STREET 1:** 333 EAST BUTTERFIELD ROAD, SUITE 400
- **CITY:** LOMBARD
- **STATE:** IL
- **ZIP:** 60148

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ENZON PHARMACEUTICALS, INC.
- **DATE OF NAME CHANGE:** 20160309

**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
**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. 19)**

**VISKASE HOLDINGS, INC.**

*(Name of Issuer)*

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

*(Title of Class of Securities)*

**—**

*(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)*

**03/25/2026**

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

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 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>**13426451.00** |
| 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>**13426451.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**13426451.00** | Aggregate amount beneficially owned by each reporting person<br>**13426451.00** | |
| 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>**93.7%** | Percent of class represented by amount in Row (11)<br>**93.7%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 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>**13426451.00** |
| 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>**13426451.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**13426451.00** | Aggregate amount beneficially owned by each reporting person<br>**13426451.00** | |
| 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>**93.7%** | Percent of class represented by amount in Row (11)<br>**93.7%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 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>**13426451.00** |
| 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>**13426451.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**13426451.00** | Aggregate amount beneficially owned by each reporting person<br>**13426451.00** | |
| 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>**93.7%** | Percent of class represented by amount in Row (11)<br>**93.7%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Item 1. Security and Issuer**

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

**(b) Name of Issuer:**
VISKASE HOLDINGS, INC.

**(c) Address of Issuer's Principal Executive Offices:**
333 East Butterfield Road, Suite 400, Lombard, IL, 60148

This statement constitutes Amendment No. 19 to the Schedule 13D relating to the shares of Common Stock, par value $0.01 per share (the "Shares"), issued by Viskase Holdings, Inc. (formerly known as 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 Amendment No. 16 to the 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:

On March 25, 2026, in connection with the closing of the previously announced Merger between the Issuer and Viskase Companies, Inc. ("Viskase") and pursuant to the terms of the IEH Support Agreement, the Reporting Persons exchanged 39,277 shares of Preferred Stock for 5,658,396 shares of the Issuer's Common Stock.

On March 26, 2026 (the "Closing Date"), the Issuer completed the Merger with Viskase pursuant to the Merger Agreement. In connection with the Merger and pursuant to the Merger Agreement, the Reporting Persons received 7,407,489 shares of the Issuer in exchange for 150,810,078 shares of Viskase. Robert Flint, Colin Kwak, and Dustin DeMaria were appointed to the Issuer's board of directors in connection with the closing of the Merger. Mr. Flint is the Chief Accounting Officer of Icahn Enterprises L.P. Mr. Kwak is the head trader at Icahn Capital LP, an affiliate of the Reporting Persons. Mr. DeMaria is a Senior Analyst at Ichan Enterprises L.P., an affiliate of the Reporting Persons.

**Item 5. Interest in Securities of the Issuer**

**(a)**
Items (a)-(c) of the Original 13D are hereby amended and supplemented as follows:

The information set forth in rows 11 and 13 of the cover pages hereto is incorporated herein by reference. The percentages set forth on the cover pages are based on 14,331,713 outstanding Shares as of March 26, 2026, as reported by the Issuer to the Reporting Persons.

**(b)**
The information set forth in rows 7-10 of the cover pages hereto is incorporated herein by reference.

**(c)**
The information set forth in Item 4 herein is incorporated herein by reference. Except for the transaction set forth in Item 4, none of the Reporting Persons effected any transaction in the Shares in the past 60 days.

### 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:** 03/27/2026

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:** 03/27/2026

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:** 03/27/2026