Tecovirimat Found Ineffective as Monotherapy for Mpox in NIH Trial

The NIH trial for SIGA Technologies' tecovirimat, also known as TPOXX, found that the antiviral drug was ineffective as a monotherapy for mpox. The study, known as STOMP, was halted after an interim analysis indicated the drug did not reduce healing time or alleviate pain. The results were similar to a parallel study in the Democratic Republic of the Congo, further questioning the drug's effectiveness for mpox.

The National Institutes of Health (NIH) recently announced the results of a clinical trial on tecovirimat, an antiviral drug also known as TPOXX, which found that it was ineffective as a monotherapy for monkeypox (mpox) [1]. The study, known as STOMP, was conducted in countries affected by the global clade II mpox outbreak and involved adults with mild to moderate symptoms who were at a low risk of developing severe disease.

The interim data analysis revealed that tecovirimat did not reduce healing time or alleviate pain among participants. Moreover, there were no safety concerns associated with the drug. Considering these findings, the study's Data Safety and Monitoring Board (DSMB) recommended stopping further enrollment of participants who were being randomized to tecovirimat or placebo.

This is not the first time tecovirimat's efficacy for mpox has been questioned. A parallel study conducted in the Democratic Republic of the Congo yielded similar results, further casting doubt on the drug's effectiveness for mpox [2].

Mpox, caused by a virus that spreads mainly through close contact, has two identified types: clades I and II. Clade II, which caused a global outbreak in 2022, continues to circulate at low levels, while clade I, which was responsible for a recent outbreak in Central and East African countries, was declared a public health emergency of international concern by the World Health Organization.

The lack of an efficacy signal for tecovirimat in the STOMP trial underscores the importance of conducting well-designed randomized clinical trials during infectious disease outbreaks. While tecovirimat has been studied for its potential use in treating mpox, the focus is now shifting towards novel antivirals and antibody-based mpox therapeutics [1].

References:
[1] NIH. (2023, March 28). NIH study finds tecovirimat was safe, did not improve mpox resolution or pain. Retrieved from https://www.nih.gov/news-events/news-releases/nih-study-finds-tecovirimat-was-safe-did-not-improve-mpox-resolution-or-pain
[2] NIAID. (2023, March 28). NIH study finds tecovirimat was safe, did not improve mpox resolution or pain. Retrieved from https://www.niaid.nih.gov/news-events/press-releases/2023/nih-study-finds-tecovirimat-was-safe-did-not-improve-mpox-resolution-or-pain
[3] WHO. (2023, March 20). Monkeypox. Retrieved from https://www.who.int/emergencies/diseases/monkeypox/en/