SIGA Technologies (SIGA) Risk Analysis

If we or others identify side effects of any approved product, or if manufacturing problems occur: - regulatory approval may be withdrawn;- reformulation of our products, additional clinical trials or other testing or changes in labeling of our products may be required;- changes to or re-approvals of manufacturing facilities we use may be required;- sales of the affected products may drop significantly;- our reputation in the marketplace may suffer; and - lawsuits, including class action suits, may be brought against us. Any of the above occurrences could harm or prevent future sales of the affected product or could increase the costs and expenses of commercializing and marketing these products, which could adversely affect our business, financial condition and results of operations.

To market our products in certain foreign jurisdictions, we need to maintain existing regulatory approvals or may need to obtain additional regulatory approvals and comply with numerous and varying regulatory requirements. The approval procedures vary among countries and can involve additional testing and differing manufacturing or labeling requirements. Coming into compliance with and maintaining compliance with such requirements may take substantial time, including prior to approval, and delay commercial activities in those jurisdictions. The foreign regulatory approval process may include all of the risks associated with obtaining FDA approval for expanded indications or new formulations of TPOXX. We may be unable to maintain existing regulatory approvals or may not be successful in obtaining additional foreign regulatory approvals on a timely basis, if at all. Regulatory approval by the FDA, which we obtained for oral and IV TPOXX, and by Health Canada, for oral TPOXX, in each case for the treatment of smallpox, or by additional foreign regulatory authorities such as  European Medicines Agency (EMA), the Japanese Pharmaceuticals and Medical Devices Agency, and the U.K. Medicines and Healthcare Products Regulatory Agency (MHRA), which we obtained for oral TPOXX for the treatment of smallpox, monkeypox ("mpox"), cowpox, and vaccinia complications following vaccination against smallpox, does not ensure continued approval in those jurisdictions or approval by additional regulatory authorities in other foreign countries or jurisdictions or by the FDA for additional indications or new formulations. The EMA and MHRA approved TPOXX under "exceptional circumstances" under the brand name Tecovirimat-SIGA. These regulators granted marketing authorizations under "exceptional circumstances" because it was not possible to obtain complete efficacy and safety information about the product due to the rarity of smallpox and other orthopoxviruses and because ethical considerations prevented conducting the necessary clinical studies. The Tecovirimat-SIGA marketing authorizations under "exceptional circumstances" are subject to certain specific obligations to gather additional data post-approval to help confirm the product's safety and efficacy. All "exceptional circumstances" marketing authorizations are subject to annual reassessments that consider whether data generated pursuant to the specific obligations continue to confirm its positive benefit-risk profile. These annual reassessments determine whether the product's marketing authorization should be maintained, changed, suspended, or withdrawn based on its benefit-risk profile. On July 24, 2025, the EMA's Committee for Medicinal Products for Human Use (CHMP) closed its third annual reassessment for Tecovirimat-SIGA and initiated a referral procedure for the product following questions over its effectiveness in the treatment of mpox. These questions were raised following receipt of results from certain non-SIGA sponsored clinical trials evaluating tecovirimat as a potential mpox treatment including the PALM007 and STOMP clinical trials. In the referral procedure, CHMP reviewed all available data on the safety and efficacy of Tecovirimat-SIGA for all its authorized indications in order to make a recommendation to the European Commission whether the marketing authorization should be maintained, modified, suspended or withdrawn. The CHMP is expected to meet in March to issue its recommendation.  We expect the CHMP will confirm the positive benefit-risk balance of Tecovirimat-SIGA as a treatment for smallpox, cowpox, and vaccinia complications, and maintain those indications in the product label.  Regarding mpox, based on the results of the mpox clinical trials, we expect the CHMP will recommend withdrawal of the mpox indication. In the UK, Tecovirimat-SIGA is undergoing an annual reassessment by the MHRA.  This reassessment, which is ongoing, is substantially similar to the EMA's annual reassessment process and could result in a similar outcome. If the CHMP recommends withdrawal of the mpox indication, and European Commission adopts the recommendation of the CHMP, it could negatively impact our anticipated revenue from Tecovirimat-SIGA and could have a material adverse effect on our business, financial condition, results of operations and growth prospects. In addition, failure to obtain or maintain approval in one jurisdiction may impact our ability to obtain approvals elsewhere. We may not be able to maintain existing approvals or may be unable to file for or receive necessary regulatory approvals to commercialize our products in new markets, in which case, our addressable market may be reduced and our ability to realize the full potential of our products and product candidates may be harmed and our business, financial condition, results of operations and prospects may be adversely affected.

We have received FDA approval for the oral and intravenous formulations of TPOXX in the U.S. for the treatment of smallpox. We have not received FDA approval for the liquid suspension/pediatric formulation or any other formulation of TPOXX. Because pharmaceutical manufacturers are only permitted to commercialize in the U.S. formulations that have received FDA approval (or in other jurisdictions according to their applicable regulatory and legal frameworks), any regulatory or legal setbacks as described above could have an adverse impact on our ability to sell TPOXX in other formulations.

The development and commercialization of additional indications for TPOXX in the U.S., such as use for smallpox post-exposure prophylaxis ("PEP"), including the testing, manufacture, safety, efficacy, recordkeeping, labeling, storage, approval, advertising, promotion, sale and distribution, are subject to comprehensive regulation by the FDA and other regulatory agencies in the United States and by comparable authorities in other countries and jurisdictions. We could fail to achieve FDA or other regulatory approval of certain indications of TPOXX, or there could be delays in such approval of TPOXX, or the approved labeling for such indications of TPOXX may differ from expectations. For example, in connection with a potential FDA label expansion of oral TPOXX for an indication covering PEP, we completed an immunogenicity trial in 2023 and originally targeted a supplemental NDA submission in 2024.  Because samples from that trial are being reanalyzed by the U.S. Centers for Disease Control and Prevention which has been impacted by recent U.S. Government shutdowns, the Company is now targeting a supplemental NDA submission within the next twelve months. Failure to obtain regulatory approval of the PEP indication may prevent us from getting procurement orders from the U.S. Government for the post-exposure prophylaxis indication and may impact other regulatory authorities' future review of other indications of TPOXX, which in turn, could adversely impact potential sales of TPOXX in other countries, and such delays or required alterations to regulatory applications could also have a material adverse effect on our future revenue opportunities.