Siga signs $113M US supply contract for mpox antiviral Tpoxx

The U.S. government has exercised a contract option and will pay $113 million for delivery of Siga Technologies’ oral smallpox antiviral Tpoxx.

The agreement builds on the deals New York City-based Siga made with the Department of Health and Human Services (HHS) the last two years for preparedness against the mpox (formerly monkeypox) virus. In July of last year, the HHS also signed on for a $113 million supply of oral Tpoxx, plus $25 million of the medicine’s intravenous formulation.

Last year, in addition to the U.S., Siga had 15 international customers, CEO Diem Nguyen said in a release.

Supplies to the U.S. account for most of Siga’s business. Last year, the company reported revenue of $140 million, which was up 26% from 2022.

Last month, Siga announced a deal to supply Tpoxx to the Association of Southeast Asian Nations (ASEAN). The 10-country organization includes Indonesia, Malaysia, the Philippines, Thailand and Vietnam.

The FDA approved Tpoxx in 2018 as the first treatment for smallpox. The virus was eradicated in 1980, but its presence in laboratories in the U.S. and Russia, plus the periodic discovery of lost vials at other sites, left lingering concerns that it could be used as a bioweapon.

The mpox virus usually affects rodents and nonhuman primates, such as monkeys. It also can be found in humans, though largely limited to Central and West Africa, according to the Mayo Clinic. In 2022, because of international travel and imported animals, mpox was found in other areas of the world including the U.S.

Those who are infected are likely to have scarring of the skin. In rare instances, the mpox virus has caused blindness and death. Bavarian Nordic’s Jynneos is the lone vaccine approved in the U.S. for mpox. It is recommended for those who have been infected and those who are at risk for infection.