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Contact:                                                       Investor Contact:
Thomas N. Konatich                                                   Dianne Will
SIGA Technologies, Inc.                               Willstar Consultants, Inc.
CFO & Acting CEO                                                  (518) 398-6222
(212) 672-9100
dwill@willstar.net


              SIGA Technologies Announces Proposed Cash Infusion of
                   up to $10 million from MacAndrews & Forbes


NEW YORK, July 11, 2003 -- SIGA Technologies, Inc. (NASDAQ:SIGA and FRANKFURT:
SGW 919 473), a biopharmaceuticals company developing products for the
prevention and treatment of serious infectious diseases, including products for
use against biological warfare agents such as smallpox, announced today that it
received a proposal for an investment in SIGA of up to an aggregate amount of
$10 million from MacAndrews & Forbes Holdings Inc., a corporation wholly-owned
by Ronald O. Perelman. SIGA has been exploring possibilities for obtaining funds
to use for research and development and, if appropriate, strategic acquisitions.
Under the proposal, MacAndrews & Forbes would invest $1,000,000 in SIGA in
exchange for 694,444 shares of SIGA common stock at a price of $1.44 per share,
and warrants to purchase an additional 381,944 shares of SIGA common stock at an
exercise price of $2.00 per share. MacAndrews & Forbes would also be granted an
option, exercisable through October 1, 2003, to invest up to an additional
$9,000,000 in SIGA on the same terms.

The members of SIGA's board of directors who are not affiliated with MacAndrews
& Forbes will separately consider the proposed investment.

The proposed investment is subject to negotiation of definitive agreements
between MacAndrews & Forbes and SIGA. Additionally, depending on the size of
MacAndrews & Forbes' investment, a portion of the transaction would be subject
to stockholder approval, in accordance with the rules of the NASDAQ.

About SIGA Technologies, Inc.

SIGA Technologies is applying bacterial genomics in the design and development
of novel products for the prevention and treatment of serious infectious
diseases, with an emphasis on products for biological warfare defense. With the
recent acquisition of substantially all the assets of Plexus Vaccine Inc., SIGA
will be able to broaden its biowarfare portfolio, and to build its capability
for extremely rapid design and delivery of synthetic vaccines for dangerous new
pathogens. Combined, SIGA and Plexus have the potential of becoming a
significant force in the discovery of vaccine and pharmaceutical agents to fight
emerging pathogens. SIGA's



product development programs emphasize the increasingly serious problem of drug
resistant bacteria and emerging pathogens. SIGA's vaccine and drug platforms are
based on its pioneering research into the structure, function and processing of
bacterial surface proteins. SIGA is leveraging these platforms through multiple
strategic partners, including Wyeth-Ayerst Laboratories (the pharmaceutical
division of American Home Products) and the National Institutes of Health. For
more information about SIGA, please visit SIGA's Web site at www.siga.com.

This news release contains certain "forward-looking statements" within the
meaning of the Private Securities Litigation Reform Act of 1995, including
statements regarding the efficacy and intended use of SIGA's technologies under
development and the likelihood that the proposed investment will be completed.
Forward-looking statements are based on management's estimates, assumptions and
projections, and are subject to uncertainties, many of which are beyond the
control of SIGA. Actual results may differ materially from those anticipated in
any forward-looking statement. Factors which may cause such differences include
the risks: that potential products that appeared promising to SIGA or its
collaborators in early research or clinical trials do not demonstrate efficacy
or safety in subsequent pre-clinical or clinical trials and that SIGA or its
collaborators will not obtain appropriate or necessary government approvals to
market products tested in such trials; and that the completion to each party's
satisfaction of due diligence, the negotiation and execution of definitive
documents, the timely receipt of necessary approvals including shareholder
approval and the satisfaction of all closing conditions may not be accomplished.

Investors and security holders are urged to read any proxy statement that may be
sent to SIGA shareholders regarding the proposed investment, when and if any
such proxy statement becomes available, because such proxy statement will
contain important information. Any such proxy statement will be filed with the
U.S. Securities and Exchange Commission by SIGA. Investors and security holders
may obtain a free copy of the proxy statement, when and if such proxy statement
is available, and any other documents filed by SIGA with the Commission at the
Commission's Web site at www.sec.gov. Any such proxy statement and these other
documents may also be obtained, when and if available, free of charge from SIGA.
SIGA's shareholders should read any such proxy statement carefully before making
a decision concerning the proposed investment.

SIGA and its respective directors, executive officers and certain other of its
respective employees may be soliciting proxies from its shareholders in favor of
the approval of the proposed investment. Information regarding the directors and
executive officers who may, under rules promulgated by the Commission, be deemed
to be participants in the solicitation of SIGA shareholders in connection with
the proposed investment is set forth in SIGA's proxy statement for its 2002
annual meeting, and additional information will be set forth in the definitive
proxy statement referred to above when and if it is filed with the Commission.

More detailed information about SIGA and the factors discussed above is set
forth in SIGA's filings with the Commission, including SIGA's Annual Report on
Form 10-K for the fiscal year ended December 31, 2002, and in other documents
that SIGA has filed with the Commission. Investors and security holders are
urged to read those documents free of charge at the Commission's Web site at
www.sec.gov. Those documents may also be obtained free of charge from SIGA. SIGA
does not undertake to publicly update or revise its forward-looking statements
as a result of new information, future events or otherwise.