NIH study finds Siga’s tecovirimat did not improve Mpox resolution or pain

The antiviral drug tecovirimat, from Siga Technologies (SIGA), did not reduce the time to lesion resolution or have an effect on pain among adults with mild to moderate clade II mpox and a low risk of developing severe disease, according to an interim data analysis from the international clinical trial called the Study of Tecovirimat for Mpox. There were no safety concerns associated with tecovirimat. Considering these definitive findings, the study’s Data Safety and Monitoring Board recommended stopping further enrollment of participants who were being randomized to tecovirimat or placebo. As the study sponsor, the National Institutes of Health’s National Institute of Allergy and Infectious Diseases accepted the DSMB’s recommendation. Given the lack of an efficacy signal, NIAID also closed enrollment into an open-label study arm for participants with or at elevated risk of severe disease that was not designed to estimate the drug’s efficacy. “The initial STOMP findings provide valuable insight to inform clade II mpox medical countermeasures and underscore the critical importance of conducting well-designed randomized clinical trials during infectious disease outbreaks,” said NIAID Director Jeanne Marrazzo, M.D., M.P.H. “Before 2022, no treatment candidate had been studied in people with mpox, and this trial is a critical step in our systematic evaluation of existing antivirals like tecovirimat while pursuing novel antivirals and antibody-based mpox therapeutics.”