Enzon Announces Agreement to Sell Specialty Pharmaceutical Business

sigma-tau to acquire business for approximately $327 million in cash plus
royalties
BRIDGEWATER, N.J.--(Business Wire)--
Enzon Pharmaceuticals, Inc. (Nasdaq: ENZN) today announced that it has entered
into a definitive agreement to sell its specialty pharmaceutical business to the
sigma-tau Group for $300 million plus an additional amount of up to $27 million
based on success milestones. Enzon will also receive royalties of 5 to 10
percent on incremental net sales above a 2009 baseline amount from Enzon`s four
marketed specialty pharmaceutical products through 2014.

Enzon`s specialty pharmaceutical business includes four marketed products:
Oncaspar, Adagen, DepoCyt, and Abelcet, as well as the manufacturing facility in
Indianapolis, Indiana which will be purchased by a US subsidiary of Sigma-Tau
Pharmaceuticals, Inc. (Maryland). Sigma-Tau Pharmaceuticals will distribute the
products in the US market.

After the sale of these assets, Enzon`s businesses will consist of its
royalties, Peg SN38 and our LNA and PEG technology platforms. "Enzon`s Board of
Directors is evaluating options to return most of the value of this sale to
shareholders" stated Alex Denner, Chairman. "We will refocus the company on our
royalty business, pipeline, and technology platforms."

"sigma-tau is a great strategic fit for this business, as they have the presence
and expertise to effectively market these products in all geographic areas,"
said Jeffrey H. Buchalter, Enzon`s president and CEO.

sigma-tau is a global R&D driven, Italian-owned pharmaceutical company
dedicated, among other areas, to developing and commercializing medicines for
rare diseases. This acquisition will expand sigma-tau`s current presence in the
US and in new therapeutic areas.

"sigma-tau is dedicated to providing novel therapeutics to patients suffering
from rare diseases and other unmet medical needs," said Claudio Cavazza,
sigma-tau`s President. "Through the acquisition of Enzon`s specialty
pharmaceutical business, we will increase our presence in the field of rare
diseases with products of great value which are the result of an outstanding
research activity. sigma-tau is determined to continue Enzon`s excellent work,
especially in the field of rare diseases which is a particularly stimulating one
as it aims at tackling life-threatening conditions which all too often affect
the very young".

The transaction may be deemed to constitute a sale of "substantially all" of
Enzon`s assets under Delaware law and, therefore, is conditioned upon the
approval by the holders of a majority of Enzon`s outstanding shares of common
stock. The transaction also is conditioned upon sigma tau`s receipt of funds
under a bank commitment letter received by sigma tau and the expiration or
termination of any applicable waiting periods under the Hart-Scott-Rodino
Antitrust Improvements Act of 1976 and any corresponding laws of other
jurisdictions. There are certain other customary conditions. The transaction is
expected to be completed during the first quarter of 2010.

Goldman, Sachs & Co. and Greenhill & Co. acted as financial advisors to Enzon,
and Skadden, Arps, Slate, Meagher & Flom LLP acted as legal advisor to the
Company.

ADDITIONAL INFORMATION AND WHERE TO FIND IT

Enzon Pharmaceuticals, Inc. ("Enzon") will file with the Securities and Exchange
Commission (the "SEC") a current report on Form 8-K, which will include the
purchase agreement. The proxy statement that Enzon plans to file with the SEC
and mail to stockholders will contain information about Enzon, the proposed
transaction and related matters. STOCKHOLDERS ARE URGED TO READ THE PROXY
STATEMENT CAREFULLY WHEN IT IS AVAILABLE, AS IT WILL CONTAIN IMPORTANT
INFORMATION THAT STOCKHOLDERS SHOULD CONSIDER BEFORE MAKING A DECISION ABOUT THE
PROPOSED TRANSACTION. In addition to receiving the proxy statement from Enzon by
mail, stockholders will be able to obtain the proxy statement, as well as other
filings containing information about Enzon, without charge, from the SEC's
website at www.sec.gov or, without charge, from Enzon at www.enzon.com. This
announcement is not a solicitation of proxy.

Enzon and its directors and executive officers and certain other members of
management may be deemed to be participants in the solicitation of proxies in
connection with the proposed transaction. Except as noted below, information
concerning Enzon's participants is set forth in the proxy statement for Enzon's
2009 annual meeting of stockholders, which was filed with the SEC on Schedule
14A on April 13, 2009 (the "2009 Proxy Statement"). Additional information
regarding the interests of Enzon's participants in the solicitation of proxies
in connection with the proposed transaction will be included in the proxy
statement to be filed with the SEC. Enzon's press releases and other information
about Enzon are available at Enzon's website at www.enzon.com.

Harold J. Levy joined Enzon's Board of Directors subsequent to Enzon's 2009
annual meeting of stockholders. Information with respect to Mr. Levy's interest
in Enzon is set forth in the Form 3 filed by him with the SEC on July 31, 2009.
Mr. Levy is the Co-President, Co-Chief Executive and Co-Chief Investment Officer
of Iridian Asset Management LLC ("Iridian"). Information with respect to
Iridian's interest in Enzon is set forth in the 2009 Proxy Statement. Mr. Levy
has shared investment and dispositive power over the shares of Enzon's common
stock held by Iridian. Mr. Levy disclaims beneficial ownership of such shares.

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, DepoCyt, Abelcet and Adagen. 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 its revenue base. Further information about Enzon and this press release
can be found on the Company`s web site at www.enzon.com.

About sigma-tau

sigma-tau is a leading, international, pharmaceutical group with a wholly
Italian-owned capital that invests in the research, development and marketing of
innovative and effective treatments to improve patient well-being and quality of
life. sigma-tau has its headquarters in Pomezia (Rome, Italy), and subsidiaries
in France, Switzerland, Belgium, the Netherlands, Portugal, Germany, the UK, USA
and India, as well as in Spain and Sudan where the Group operates two production
facilities. It has over 2300 employees and an extensive network of licensees
worldwide. sigma-tau was founded in Italy in 1957 and achieved a global turnover
of € 613 million ($909 million) in 2008. sigma-tau SpA consistently invests
approximately 16% of its annual turnover in R&D. sigma-tau`s R&D staff of
approximately 400 people is currently running 46 R&D projects. A total of 13
NCEs and 12 known molecular entities in 33 different indications are at various
stages of development. Among them, several are aimed at rare diseases.
Therapeutic areas in which the company's research and development are focused
include metabolism, neurology, cardiovascular, oncology and immunology.

sigma-tau website: www.sigma-tau.it

Sigma-Tau Pharmaceuticals, Inc. (STPI) is the U.S. based, wholly owned
subsidiary of the sigma-tau Group, and is dedicated solely to the development
and commercialization of medicines for patients with rare diseases. With more
than 6,000 identified rare diseases that affect approximately 25 million
patients in the United States, STPI places its considerable scientific resources
behind the discovery and development of compounds that benefit the few. STPI is
based in Gaithersburg, Maryland.

For more information about the company, visit www.sigmatau.com

Company Contact - Gregg Lapointe, CEO, Phone # 301-670-5459 or Marc Tewey, Phone
# 301-670-1518

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 year 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.

Enzon Pharmaceuticals, Inc.
Craig Tooman, 908-541-8777
EVP, Finance and Chief
Financial Officer

Copyright Business Wire 2009