Tecovirimat (TPOXX) has been used to treat patients with mpox disease, including those with severe disease, during the multinational outbreak that began in May 2022. However, the safety and efficacy of TPOXX for treating mpox has not been established. The National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, is now sponsoring the Study of Tecovirimat for Human Mpox Virus (STOMP). The STOMP trial is designed to assess whether tecovirimat is safe and effective for treating mpox in people with the disease.

The STOMP trial aims to enroll more than 500 people worldwide and includes a remote enrollment option at some study sites. This research remains a public health priority even when mpox disease burden is low in the United States. To help meet mpox response goals, CDC is urging clinicians to let mpox patients know that oral tecovirimat is available through STOMP and encourage them to enroll. 

The STOMP study protocol is open to children and adults of all races and genders, people living with HIV, and pregnant and breastfeeding people. It is also open to people with less severe disease who might not be eligible for treatment with tecovirimat under CDC’s expanded access-Investigational New Drug (EA-IND) protocol. However, people who have had prior treatment with tecovirimat or who need tecovirimat treatment intravenously are not eligible for STOMP.

Clinicians should inform patients about STOMP so they can consider enrolling in the study, but enrollment in the study is voluntary. Patients who decline to take part, or who do not meet the criteria to participate, can still receive tecovirimat if they meet treatment eligibility criteria (e.g., have severe disease or are at increased risk for severe disease) under CDC’s EA-IND.