Tecovirimat

Tecovirimat, sold under the brand name Tpoxx, is an antiviral with activity against orthopoxviruses such as smallpox and monkeypox. It is the only antipoxviral drug approved in the United States.
The drug works by blocking cellular transmission of the virus, thus preventing the disease. Tecovirimat has been effective in laboratory testing; it has been shown to protect animals from monkeypox and rabbitpox and causes no serious side effects in humans. However, tecovirimat has never been used to treat a human with smallpox due to the disease's eradication.
Two million doses of tecovirimat are stockpiled in the US Strategic National Stockpile should an orthopoxvirus-based bioterror attack occur.
The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication.
Clinical study.
The results of clinical trials involving tecovirimat supports its use against smallpox and other related orthopoxviruses. It has shown potential for a variety of uses including preventive healthcare, as a post-exposure therapeutic, as a therapeutic and an adjunct to vaccination.
Tecovirimat can be taken orally and has recently been granted permission to conduct Phase II trials by the U.S. Food and Drug Administration (FDA). In Phase I trials tecovirimat was generally well tolerated with no serious adverse events. Due to its importance for biodefense, the FDA has designated tecovirimat for 'fast-track' status, creating a path for expedited FDA review and eventual regulatory approval. On 13 July 2018, the FDA announced approval of tecovirimat.
Mechanism of action.
Tecovirimat inhibits the function of a major envelope protein required for the production of extracellar virus. Thus the virus is prevented from leaving an infected cell and the spread of the virus within the body is prevented.
Use.
Tecovirimat was first used for treatment in December 2018 after a laboratory-acquired vaccinia virus infection.
Society and culture.
Originally researched by the National Institute of Allergy and Infectious Diseases, the drug was previously owned by Viropharma and discovered in collaboration with scientists at USAMRIID. It is currently owned and manufactured by Siga Technologies, a pharmaceutical company in the biodefense arena that won a government contract to develop the drug.