The US government is paying Siga $113 million to stockpile additional courses of the smallpox and mpox treatment known as Tpoxx.
The project falls under the government’s strategic preparedness plan and was financed either fully or in part by the HHS. It’s unknown how many doses the $113 million contract affords and a spokesperson for Siga declined to say.
Siga CEO Diem Nguyen said in a statement Friday that the order would help “support sizable and consistent action when needed.”
It’s the second such contract in as many years after the US paid Siga $113 million for oral Tpoxx doses in July 2023 plus $25 million worth of an intravenous version.
Siga and Tpoxx ascended two years ago as cases of mpox (formerly known as monkeypox) rose across the country. The treatment is approved to treat smallpox and it was used off-label against mpox since both viruses are in the family of orthopoxviruses.
Though the US government sought out Tpoxx during the mpox outbreak to help stymie the spread, federal agencies maintained caution about its use. The FDA made clear that the safety and efficacy against mpox had not been established in humans and that the risk of drug resistance meant it should be used “in a judicious manner.” The NIH’s National Institutes for Allergy and Infectious Diseases (NIAID) launched a Phase 3 trial in September 2022 testing Tpoxx as a treatment for mpox, which is still recruiting patients.
During the summer of 2022, Siga’s shares rose from $6.87 per share at the end of April to a peak of $24.75 in mid-August. The end of the mpox outbreak took the company out of the limelight and its value has since fallen, now trading at roughly $9.20 per share.