US begins clinical trial to evaluate antiviral for monkeypox

The National Institute of Health (NIH) has begun a phase-III clinical trial to evaluate the antiviral tecovirimat (TPOXX) against monkeypox infection. Study investigators aim to enroll more than 500 people from clinical research sites nationwide.

Tecovirimat, manufactured by SIGA Technologies, is approved by the US Food and Drug Administration (FDA) for the treatment of smallpox. The drug prevents the virus from spreading in the body by preventing virus particles from exiting human cells by targetting a protein found on both the variola virus, which causes smallpox, and the monkeypox virus, NIH said in a statement.

“Monkeypox can be an extremely painful infection that lasts for week. We currently lack efficacy data that would help us understand how well this drug may mitigate painful monkeypox symptoms and prevent serious outcomes. This clinical trial was designed to answer those important questions,” said Anthony S Fauci, MD, Director, National Institute of Allergy and Infectious Diseases (NIAID), in the statement.

The statement informed that the clinical trial is led by Timothy Wilkin, MD, Professor, Medicine, Weill Cornell Medicine, New York City. Adults and children of any age with monkeypox are eligible to enroll in the trial. Adults with severe monkeypox virus infection or those at high risk for severe disease including individuals with underlying immune deficiency, a history of or active inflammatory skin conditions, pregnant people and children, all will be enrolled in an open-label arm in which all participants receive tecovirimat. Other adult participants—530 total—will be randomly assigned in a 2:1 ratio to receive tecovirimat or placebo pills. Tecovirimat capsules are taken by mouth for 14 days, and the dose is based on the participant’s weight. This part of the trial is double-blind.

Investigators will gather data to determine if participants receiving tecovirimat heal more quickly (all lesions scabbed over or flaked off) compared with those taking placebo. They also will examine tecovirimat’s impact on pain scores, rates of progression to severe disease, clearance of monkeypox virus from various samples, and its safety, among other data. This study will also provide critical data on the optimal dosing and safety of tecovirimat in children and people who are pregnant, the statement added.

Participants will be followed for at least eight weeks and will be asked to fill out a symptom diary, do daily skin checks at home and attend virtual and in-person clinic appointments. They will also undergo physical exams, and will be asked to provide blood and other bodily fluid samples, including swabbing fluid from their lesions, it further said.

Data on the safety and efficacy of tecovirimat will be submitted to the FDA. An independent Data and Safety Monitoring Board (DSMB) will monitor participant safety throughout the duration of the study. The trial timeline will depend on the pace of enrollment, concluded the statement.