Enzon Treats Patients with Survivin Antagonist.

-- Enzon's compound advances into the clinic for patients with solid tumors and lymphomas --

BRIDGEWATER, N.J. -- Enzon Pharmaceuticals, Inc. (Nasdaq: ENZN) today announced that several patients have been treated with its Survivin antagonist. The U.S. Food and Drug Administration (FDA) recently accepted the Company's Investigational New Drug (IND) application for the use of its Survivin antagonist.

"Survivin is considered one of the most promising cancer targets and we are pleased that we were able to quickly advance this important compound into patients," said Jeffrey H. Buchalter, chairman and chief executive officer of Enzon.

Survivin is a key protein that controls cancer growth by playing a significant role in cell division, as well as inhibiting the programming that controls cell death. The Enzon Survivin antagonist was developed using the Locked Nucleic Acid technology. In preclinical animal studies, the molecule (EZN-3042) inhibited Survivin expression and tumor growth. It also potentiated the antitumor activity of taxol, an approved cancer therapeutic. Enzon licensed the Survivin antagonist from Santaris Pharma A/S.

About Enzon

Enzon Pharmaceuticals, Inc. is a biopharmaceutical company dedicated to developing, manufacturing and commercializing important medicines for patients with cancer and other life-threatening conditions. The Company has a portfolio of four marketed products, Oncaspar[R], DepoCyt[R], Abelcet[R] and Adagen[R]. Enzon's drug development programs utilize several cutting-edge approaches, including its industry-leading PEGylation technology platform and the Locked Nucleic Acid (LNA) technology. Enzon's PEGylation technology was used to develop two of its products, Oncaspar and Adagen, and has created a royalty revenue stream from licensing partnerships for other products developed using the technology. Enzon also engages in contract manufacturing for several pharmaceutical companies to broaden our revenue base.

Further information about Enzon and this press release can be found on the Company's web site at www.enzon.com.

Forward Looking Statements There are forward-looking statements contained herein, which can be identified by the use of forward-looking terminology such as the words "believes," "expects," "may," "will," "should," "potential," "anticipates," "plans" or "intends" and similar expressions. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause actual results, events or developments to be materially different from the future results, events or developments indicated in such forward-looking statements. Such factors include, but are not limited to the timing, success and cost of clinical studies; the ability to obtain regulatory approval of products, market acceptance of, and continuing demand for, Enzon's products and the impact of competitive products and pricing. A more detailed discussion of these and other factors that could affect results is contained in our filings with the U.S. Securities and Exchange Commission, including our annual report on Form 10-K for the period ended December 31, 2008. These factors should be considered carefully and readers are cautioned not to place undue reliance on such forward-looking statements. No assurance can be given that the future results covered by the forward-looking statements will be achieved. All information in this press release is as of the date of this press release and Enzon does not intend to update this information.