SIGA Technologies : NCT USA Conference Presentation

Antiviral Drugs: Adapting Capabilities for an Effective Response to Future Epidemic Outbreaks

Phil Gomez, Ph.D.

Chief Executive Officer, SIGA Technologies, Inc. September 2021

Slide 1

REA53 Added Date

Robin E. Abrams, 8/19/2021

Forward Looking Statements

The statements made in this presentation may include forward-looking statements regarding the treatment of smallpox and other orthopoxvirus infections, the development and attributes of SIGA Technologies, Inc. ("SIGA") products, and the future operations, opportunities or financial performance of SIGA. Although we believe that the expectations contained in this presentation are reasonable, these forward-looking statements are only estimations based upon the information available to SIGA as of the date of this presentation. Except as required by law, we expressly disclaim any responsibility to publicly update or revise our forward-looking statements, whether as a result of new information, future events or otherwise. Thus, the forward-looking statements herein involve known and unknown risks and uncertainties and other important factors such that actual future operations, opportunities or financial performance may differ materially from these forward-looking statements.

Undue reliance should not be placed on forward looking statements, which speak only as of the date hereof. All forward- looking statements contained herein are qualified in their entirety by the foregoing cautionary statements.

For a more detailed discussion of our risks, see the Risk Factors section in SIGA's Annual Report on Form 10-K for the fiscal year ended December 31, 2020 filed with the SEC and our other filings with the SEC, including our most recent Quarterly Report, all of which are available on our website, www.siga.com.

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COVID-19 has Shown the Impact of a Pandemic and Magnitude of Required Response

Trillions in Economic Impact; >4,260,000 Fatalities Worldwide;

Over $100B in the U.S. alone for supplemental funding for Medical Countermeasures

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$62 billion for ASPR generally to prevent, prepare for, and respond to COVID-19, domestically or internationally, including the development of necessary countermeasures and vaccines

$19 billion for the Strategic National Stockpile for critical medical supplies, personal protective equipment, and life-saving medicine

$10.5 billion for BARDA to advance construction, manufacturing, and purchase of vaccines and therapeutics

$522 million for FDA review activities related to COVID-19 medical countermeasures

$2.4 billion for NIH to expand on prior research plans, including developing an improved understanding of the prevalence of COVID19, study the long term impacts of COVID19, and support clinical trials

Totals don't include the over $190 billion in other public health costs to the federal government, including direct reimbursements to hospitals and health systems, and funding for state and local response efforts

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Effective Response Requires Development and Stockpiling of Broad-Spectrum Antivirals with Diverse Mechanisms of Action Readily Deployable for Future Epidemics

"The scientific community really should have developed universal antivirals against SARS. Then we would have had something in the stockpile for the emergence of COVID"

Robert Webster, emeritus member of St Jude Children's Research Hospital in Memphis, Tennessee

Promising strategies include

host-targeted and

immunomodulatory

compounds e.g. interferon

Broad

Spectrum

	All Viruses
Example Antivirals	None currently; equivalent
to penicillin antibiotic or
	azole antifungals

Limited; remain hard to	More realistic strategies that	Highly targeted,
develop including need to	focus on a viral family, e.g. a	effective with low off-
balance broad-spectrum	pan-coronavirus inhibitor, or	target effects; long
activity against toxicity	even a subset of a family	development timeline

Narrow

Spectrum

Groups of viruses	Viral Family	Specific Individual Virus
Broad spectrum RNA virus activity e.g.	Acyclovir against various herpes	90% of approved antiviral
Favipiravir (Influenza, Ebola, Lassa);	family viruses e.g. HSV-1,HSV-2,	drugs, e.g. Amantadine
Nucleoside analogs e.g. Remdesivir	and VZV; TPOXX against all	(Influenza A), Maraviroc (HIV)
(filoviruses, coronaviruses) and Ribavirin	orthopox viruses	and Simeprevir (HCV)

Source: The race for antiviral drugs to beat COVID - and the next pandemic. https://www.nature.com/articles/d41586-021-00958-4

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