SIGA Presents Update on ST-246 Development to the World Health Organization

NEW YORK, Nov. 5, 2009 (GLOBE NEWSWIRE) -- SIGA Technologies, Inc.
(Nasdaq:SIGA), a company specializing in the development of pharmaceutical
agents to fight bio-warfare pathogens, today announced that Dr. Dennis E. Hruby,
SIGA's Chief Scientific Officer, presented SIGA's progress in developing its
lead drug candidate, ST-246, an antiviral for smallpox and other
orthopoxviruses, to the World Health Organization (WHO) Advisory Committee on
Variola Virus Research on November 4, 2009 in Geneva, Switzerland.

Dr. Hruby commented on the presentation: "We are very pleased to once again
provide an update on our progress before the World Health Organization. Since
our last presentation to the Advisory Committee on Variola Virus Research, SIGA
has achieved a number of important milestones with ST-246, including the
completion of nonclinical toxicology studies that support safety in humans and
the successful treatment of a patient suffering from complications due to
exposure to a live vaccinia-vectored rabies vaccine."

Dr. Hruby continued, "This meeting also comes at a very important time for SIGA,
as an acquisition of ST-246 is currently being considered for the National
Strategic Stockpile following our response to a request for proposal from the
Department of Health and Human Services that was issued in March of 2009."

About SIGA Technologies, Inc.

SIGA Technologies is applying viral and bacterial genomics and sophisticated
computational modeling 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. SIGA believes that it is a leader in
the development of pharmaceutical agents to fight potential bio-warfare
pathogens. SIGA has antiviral programs targeting smallpox and other Category A
pathogens, including arenaviruses (Lassa fever, Junin, Machupo, Guanarito,
Sabia, and lymphocytic choriomeningitis), dengue virus, and the filoviruses
(Ebola and Marburg). For more information about SIGA, please visit SIGA's web
site at http://www.siga.com/.

The SIGA Technologies, Inc. logo is available at
http://www.globenewswire.com/newsroom/prs/?pkgid=4504

Forward-looking Statements

This press release contains or implies certain "forward-looking statements"
within the meaning of the Private Securities Litigation Reform Act of 1995, as
amended, including statements regarding the efficacy of potential products, the
timelines for bringing such products to market and the continued development and
possible eventual approval of such products. Forward-looking statements are
based on management's estimates, assumptions and projections, and are subject to
uncertainties, many of which are beyond SIGA's control. Actual results may
differ materially from those anticipated in any forward-looking statement.
Factors that may cause such differences include the risks that (i) potential
products that appear promising to SIGA or its collaborators cannot be shown to
be efficacious or safe in subsequent pre-clinical or clinical trials, (ii) SIGA
or its collaborators will not obtain appropriate or necessary governmental
approvals to market these or other potential products, (iii) SIGA may not be
able to obtain anticipated funding for its development projects or other needed
funding, (iv) SIGA may not be able to secure funding from anticipated government
contracts and grants, (v) SIGA may not be able to secure or enforce sufficient
legal rights in its products, including sufficient patent protection for its
products, (vi) regulatory approval for SIGA's products may require further or
additional testing that will delay or prevent approval, (vii) the Biomedical
Advanced Research & Development Authority may not complete the procurement set
forth in its solicitation for the acquisition of a smallpox antiviral for the
strategic national stockpile, or may complete it on different terms; (viii) the
volatile and competitive nature of the biotechnology industry may hamper SIGA's
efforts, (ix) changes in domestic and foreign economic and market conditions may
adversely affect SIGA's ability to advance its research or its products, (x)
changing federal, state and foreign regulation on SIGA's businesses may
adversely affect SIGA's ability to advance its research or its products, (xi)
the registration statement may not become effective or may become effective only
after substantial delay, and (xii) market conditions may not permit an offering
of these securities or be sufficiently attractive to market participants to
allow any offering to succeed. More detailed information about SIGA and risk
factors that may affect the realization of forward-looking statements, including
the forward-looking statements in this press release, is set forth in SIGA's
filings with the Securities and Exchange Commission, including SIGA's Annual
Report on Form 10-K for the fiscal year ended December 31, 2008, and in other
documents that SIGA has filed with the Commission. SIGA urges investors and
security holders to read those documents free of charge at the Commission's Web
site at http://www.sec.gov. Interested parties may also obtain those documents
free of charge from SIGA. Forward-looking statements speak only as to the date
they are made, and, except for any obligation under the U.S. federal securities
laws, SIGA undertakes no obligation to publicly update any forward-looking
statement as a result of new information, future events or otherwise.

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CONTACT: KCSA Strategic Communications
Todd Fromer
212-896-1215
Tfromer@kcsa.com
Marybeth Csaby
212-896-1236
mcsaby@kcsa.com