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Completed

NCT Number: NCT05559099

Tecovirimat for Treatment of Monkeypox Virus

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.

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Key information

Conditions

Monkeypox Animal Diseases DNA Virus Infections Infections Mpox, Monkeypox Poxviridae Infections Primate Diseases Rodent Diseases Virus Diseases

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

L'Hôpital Général de Référence de Kole, Kole, Democratic Republic of the Congo

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About this study

This is a randomized, placebo-controlled, double-blind study to test the antiviral drug tecovirimat for the treatment of adults and children with laboratory-confirmed monkeypox virus (MPXV) disease at participating sites in the Democratic Republic of Congo. Eligible and consented participants will be randomized 1:1 to receive either oral tecovirimat or placebo, each administered in the hospital with standard-of-care (SOC) treatment for 14 days. Participants will be followed for 28 days with an optional visit at Day 59 for long-term assessment.

If a participant reaches full body lesion resolution but subsequently develops at least one new lesion consistent with mpox after discharge but while still enrolled in the study, they will be eligible to make a sick visit and will be offered standard of care for mpox.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Tecovirimat Oral Capsule

Drug

200 mg capsules

Number of capsules and frequency of dosage will be based on participant weight:

  • ≥120 kg: three capsules three times a day (total daily tecovirimat dose: 1,800 mg)
  • 40 to <120 kg: three capsules twice a day (total daily tecovirimat dose: 1,200 mg)
  • 25 to <40 kg: two capsules twice a day (total daily tecovirimat dose: 800 mg)
  • 13 to <25 kg: one capsule twice a day (total daily tecovirimat dose: 400 mg)
  • 6 to <13 kg: ½ the contents of a capsule twice daily (total daily tecovirimat dose: 200 mg)
  • 3 to <6 kg: ¼ the contents of a capsule twice daily (total daily tecovirimat dose: 100 mg)

Other names: TPOXX

Placebo

Drug

Capsules to match tecovirimat

Primary outcomes

  1. Time to Lesion Resolution

    Time frame: Up to day 28

    Number of days from randomization to the first day on which all lesions on the total body are scabbed or desquamated or a new layer of epidermis has formed.

Secondary outcomes

  1. Time to Lesion Resolution for Participants With Symptom Onset Less Than or Equal to 7 Days Before Randomization

    Time frame: up to day 28

    Number of days to the first day on which all lesions on the total body are scabbed or desquamated or a new layer of epidermis has formed.

  2. Time to Lesion Resolution for Participants With Symptom Onset Greater Than 7 Days Before Randomization

    Time frame: up to day 28

    Number of days to the first day on which all lesions on the total body are scabbed or desquamated or a new layer of epidermis has formed.

  3. Number and Percentage of Participants With Negative Blood PCR Results

    Time frame: day 14

    Percentage of participants with negative blood sample MPXV PCR results 14 days post-randomization, out of those positive at baseline

  4. Number and Percentage of Participants With Negative Oropharyngeal Swab PCR Results

    Time frame: day 14

    Number and percentage of participants with negative oropharyngeal swab MPXV PCR results 14 days post-randomization, out of those positive at baseline

  5. Number and Percentage of Participants With Negative Lesion Swab PCR Results

    Time frame: day 14

    Number and and percentage of participants with negative lesion swab MPXV PCR results 14 days post-randomization, of those positive at baseline

  6. Mortality Within the First 28 Days Post-randomization

    Time frame: up to day 28

    Number of deaths post-randomization

  7. Incidence of Non-fatal Serious Adverse Events Requiring Permanent Drug Discontinuation

    Time frame: Up to day 14

    Number of participants with a non-fatal serious adverse event requiring permanent drug discontinuation through the end of the treatment period (14 days)

  8. Incidence of Non-fatal Adverse Events Requiring Permanent Drug Discontinuation

    Time frame: Up to day 14

    Number of participants with a non-fatal adverse event requiring permanent drug discontinuation through the end of the treatment period (14 days)

  9. Incidence of Adverse Events

    Time frame: up to day 28

    Number of participants with an adverse event up to day 28

  10. Incidence of Bacterial Infection Adverse Events

    Time frame: up to day 28

    Number of participants with a bacterial infection adverse event up to day 28

Sponsors and collaborators

Lead sponsor

National Institute of Allergy and Infectious Diseases (NIAID)

Nih

Collaborators

  • Institut National de Recherche Biomédicale. Kinshasa, République Démocratique du Congo

Registry information

Official study title

A Randomized, Placebo-controlled, Double-blinded Trial of the Safety and Efficacy of Tecovirimat for the Treatment of Adult and Pediatric Patients With Monkeypox Virus Disease

Important dates

Study start
2022
Primary completion
2024
Study completion
2024
First posted
Sep 29, 2022
Registry last updated
Oct 9, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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