Phase 2
N=597
Tecovirimat for Treatment of Monkeypox Virus
Monkeypox
Bottom Line
View on ClinicalTrials.gov: NCT05559099 ↗Enrolled (actual)
597
Serious AEs
5.0%
Results posted
Oct 2025
Primary outcome: Primary: Time to Lesion Resolution — 7; 8 Days
Study Design & Population
- Study type
- Interventional
- Phase
- Phase 2
- Interventions
- Tecovirimat Oral Capsule (Drug); Placebo (Drug)
- Age
- Pediatric, Adult, Older Adult
- Sex
- All
- Sponsor
- National Institute of Allergy and Infectious Diseases (NIAID)
- Primary completion
- Sep 2024
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY Time to Lesion Resolution |
7; 8 | — |
| SECONDARY Time to Lesion Resolution for Participants With Symptom Onset Less Than or Equal to 7 Days Before Randomization |
7; 8 | — |
| SECONDARY Time to Lesion Resolution for Participants With Symptom Onset Greater Than 7 Days Before Randomization |
8; 8 | — |
| SECONDARY Number and Percentage of Participants With Negative Blood PCR Results |
140; 141 | — |
| SECONDARY Number and Percentage of Participants With Negative Oropharyngeal Swab PCR Results |
144; 136 | — |
| SECONDARY Number and Percentage of Participants With Negative Lesion Swab PCR Results |
256; 259 | — |
| SECONDARY Mortality Within the First 28 Days Post-randomization |
3; 4 | — |
| SECONDARY Incidence of Non-fatal Serious Adverse Events Requiring Permanent Drug Discontinuation |
0; 2 | — |
| SECONDARY Incidence of Non-fatal Adverse Events Requiring Permanent Drug Discontinuation |
1; 0 | — |
| SECONDARY Incidence of Adverse Events |
196; 199 | — |
| SECONDARY Incidence of Bacterial Infection Adverse Events |
23; 27 | — |
Summary
The purpose of this study is to find out if tecovirimat is a safe and effective drug to treat monkeypox (mpox) in combination with standard of care (SOC). Participants will be randomly assigned to receive oral tecovirimat plus SOC or placebo plus SOC for 14 days.
Eligibility Criteria
This study has no age restriction.
Inclusion Criteria
- Laboratory-confirmed monkeypox virus infection as determined by PCR obtained from blood, oropharynx, or skin lesion within 48 hours of screening
- Monkeypox illness of any duration provided that the patient has at least one active, not yet scabbed, lesion
- Weight ≥3 kg
- Men and non-pregnant women of reproductive potential must agree to use effective means of contraception when engaging in sexual activities that can result in pregnancy, from the time of enrollment through the end of study participation. Acceptable methods of contraception include the following:
- Hormonal contraception
- Male or female condom
- Diaphragm or cervical cap with a spermicide
- Intrauterine device
- Stated willingness to comply with all study procedures (including required inpatient stay) and availability for the duration of the study
- Ability to provide informed consent personally or by a legally or culturally acceptable representative if the patient is unable to do so
Exclusion Criteria
- Current or planned use of a meglitinide (repaglinide, nateglinide)
- Planned use of midazolam while on study drug
- Severe anemia, defined as hemoglobin <7 g/dL
- Current or planned use of another investigational drug at any point during study participation
- Patients who, in the judgement of the investigator, will be at significantly increased risk as a result of participation in the study
- Participants who are unable to safely swallow oral medications, such as those who are at risk of aspiration
Data sourced from ClinicalTrials.gov (NCT05559099). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.