New Medicines

Tecovirimat SIGA (EU/UK), TPOXX (US) Smallpox, monkeypox, cowpox, and complications from Vaccinia infection - treatment


Tecovirimat SIGA (EU/UK), TPOXX (US)
New molecular entity
SIGA Technologies
SIGA Technologies

Development and Regulatory status

Approved (Licensed)
Approved (Licensed)
September 2022
Sep 22Available in the UK. A rapid policy statement published on 20 September 2022 by the four UK governments, says that hospitalised patients weighing 13kg ore more with PCR-confirmed monkey pox are eligible for antiviral treatment with tecovirimat if they have one or more criteria for severe or complicated disease. These criteria include intractable pain, neurological problems, immunodeficiency or extensive cutaneous disease. Supply is being managed by specialist regional adult infectious centres [8].
Jul 22Approved in UK for the treatment of smallpox, monkeypox, cowpox, and vaccinia complications following vaccination against smallpox in adults and children with a body weight of at least 13kg [7].
Jan 22Approved in the EU [6
Nov 21Recommended for EU approval, under exceptional circumstances, by CHMP “for the treatment of smallpox, monkeypox and cowpox in adults and children with body weight at least 13 kg, and to treat complications due to replication of vaccinia virus following vaccination against smallpox, in adults and children with body weight at least 13 kg. Tecovirimat SIGA should be used in accordance with official recommendations”. Tecovirimat SIGA will be available as 200 mg hard capsules [5].
Jul 20Filed in EU via centralised procedure for treatment of smallpox, monkeypox, cowpox, and complications from Vaccinia infection [4].

Jul 18: US FDA approves tecovirimat for the treatment of Smallpox.[2,3]

May 18: FDA´s Antimicrobial Drugs Advisory Committee adopts a positive opinion for the use of tecovirimat for Smallpox.[3]

Dec 17: Filed for approval. FDA assigns target final action date of Aug 18 (priority review under the Material Threat Countermeasure PRV program enacted by the 2016 21st Century Cures Act).[3]


Viral envelope protein (p37) inhibitor, inhibits extracellular viral replication.
Smallpox was a contagious, disfiguring disease which used to be a common cause of morbidity and mortality worldwide. Naturally-occurring smallpox has now been eradicated but ongoing interest in this disease lies both in the success of the eradication programme and in its potential as a biological weapon. [1,2]
Smallpox, monkeypox, cowpox, and complications from Vaccinia infection - treatment

Trial or other data

Jul 18FDA approval is based on extensive positive efficacy data in animal studies and human clinical safety data (n=700 human volunteers) without any drug-related serious adverse events. [2,3]
Aug 16Completion of PIII double-blind, placebo-controlled, randomised trial in 422 human volunteers that assessed the safety, tolerability and pharmacokinetics of oral tecovirimat 400mg or 600mg daily for 14 days in healthy volunteers (SIGA 246-008; NCT02474589). It was well tolerated and no serious adverse events observed.[3]