Business Description

Overview SIGA Technologies, Inc. is referred to throughout this report as “SIGA,” “the Company,” “we” or “us.” We are a commercial-stage pharmaceutical company. The Company sells its lead product, TPOXX® (“oral TPOXX®,” also known as "tecovirimat," "Tecovirimat-SIGA," or "TEPOXX (tecovirimat)" in certain international markets), to the U.S. Government and international governments (including government affiliated entities). In certain international markets, the Company may sell TPOXX® through a distributor. Additionally, the Company sells the intravenous formulation of TPOXX® ("IV TPOXX®") to the U.S. Government. TPOXX® is an antiviral drug for the treatment of human smallpox disease caused by variola virus. On July 13, 2018, the United States Food & Drug Administration (“FDA”) approved the oral formulation of TPOXX® for the treatment of smallpox. The Company has been delivering oral TPOXX® to the U.S. Strategic National Stockpile ("Strategic Stockpile") since 2013. On May 18, 2022, the FDA approved IV TPOXX® for the treatment of smallpox. In addition to being approved by the FDA, oral TPOXX® (tecovirimat) has received regulatory approval from the European Medicines Agency ("EMA"), Health Canada, the Medicines and Healthcare Products Regulatory Agency ("MHRA") of the United Kingdom, and the Japanese Pharmaceuticals and Medical Devices Agency ("PMDA"). The EMA, MHRA and PMDA approved oral TPOXX® for the treatment of smallpox, monkeypox ("mpox"), cowpox, and vaccinia complications following vaccination against smallpox. Health Canada approved TPOXX® for the treatment of smallpox. 2 Table of Contents TPOXX® was authorized under “exceptional circumstances” by the EMA and the MHRA, 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. With respect to the regulatory approvals by the EMA, PMDA, MHRA and Health Canada, oral tecovirimat represents the same formulation approved by the FDA in July 2018 under the brand name TPOXX®. In connection with a potential FDA label expansion of oral TPOXX® for an indication covering smallpox post-exposure prophylaxis (“PEP”), the Company has completed an immunogenicity trial and an expanded safety trial.…