NEW YORK, Feb 24, 2009 (GlobeNewswire via COMTEX News Network) -- SIGA Technologies, Inc. (Nasdaq:SIGA), a company specializing in the development of pharmaceutical agents to fight biowarfare pathogens, today announced the results of a non-human primate study by the Southern Research Institute (SRI) that suggests that ST-246(r) can be used in combination with a well-known smallpox vaccine and may improve the safety profile of the vaccine.

The study investigated the efficacy of concurrent administration of ST-246, SIGA's smallpox antiviral candidate drug, and Acambis' ACAM2000(tm) smallpox vaccine in non-human primates. When concurrently administered, ST-246 appears to reduce the size and intensity of the lesion formed at the vaccine administration site while the vaccine still confers similar levels of protection in the test animals compared to animals given vaccine alone, based on a subsequent challenge with lethal doses of monkeypox virus. Pending immunological evaluations will shed further light on the overall impact of concomitant ST-246 administration on vaccine efficacy. This favorable initial primate data should spur further studies to investigate this drug/vaccine combination approach.

The results of the study will be presented by Dr. Peter Silvera of SRI on February 24, 2009 at the 7th Annual ASM Biodefense and Emerging Diseases Research Meeting in Baltimore, Maryland. The National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, funded the SRI study under contract no. N01-AI-30063.

Dr. Dennis E. Hruby, SIGA's Chief Scientific Officer, commented, "We are encouraged by these favorable findings, particularly as the results show that ST-246 administration may reduce lesion size and intensity at the vaccination site, as well as the occasionally serious side effects that the smallpox vaccine can cause. We are gratified by this support for our belief that our antiviral drug candidate has the potential to lessen or even prevent some of the more severe side effects."

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 biowarfare pathogens. In addition to small pox, SIGA has antiviral programs targeting 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 website at http://www.siga.com.

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Forward-Looking Statement

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 (a) 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, (b) SIGA or its collaborators will not obtain appropriate or necessary governmental approvals to market these or other potential products, (c) SIGA may not be able to obtain anticipated funding for its development projects or other needed funding, (d) SIGA may not be able to secure funding from anticipated government contracts and grants, (e) SIGA may not be able to secure or enforce sufficient legal rights in its products, including sufficient patent protection for its products, and (f) regulatory approval for SIGA's products may require further or additional testing that will delay or prevent approval. 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, 2007, 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.

Please note: ACAM2000(tm) is a trademark of Acambis. ST-246(r) is a registered trademark of SIGA Technologies, Inc.

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SOURCE: SIGA Technologies, Inc.

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

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