Regulation FD Disclosure (Form 8-K)

On March 25, 2026, Enzon Pharmaceuticals, Inc. issued a press release announcing the completion of the exchange offer relating to its Series C Non-Convertible Redeemable Preferred Stock. A copy of the press release is attached as Exhibit 99.1hereto and incorporated herein by reference.

In accordance with General Instruction B.2 of Form 8-K, the foregoing information, including Exhibit 99.1, shall not be deemed "filed" for the purposes of Section 18 of the Exchange Act of 1934, as amended (the "Exchange Act"), or otherwise subject to the liabilities of that section, nor shall such information, including Exhibit 99.1, be deemed incorporated by reference into any filing under the Securities Act or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.