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Study of Tecovirimat for Huma...

Study of Tecovirimat for Human Mpox Virus

Last Updated: 2026-02-10

Study Results

Results available

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Basic Information

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Recruitment Status

TERMINATED

Clinical Phase

PHASE3

Total Enrollment

719 participants

Study Classification

INTERVENTIONAL

Study Start Date

2022-09-08

Study Completion Date

2025-02-22

Brief Summary

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The purpose of this study was to see if tecovirimat is safe and successful at treating mpox. The main questions were whether tecovirimat reduced time to lesion resolution and pain compared to placebo (no treatment).

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Detailed Description

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This phase 3, randomized, placebo-controlled, double-blind clinical trial evaluated the efficacy of tecovirimat for the treatment of mpox. Participants who had or were at higher risk for severe disease because of their age or medical history, were pregnant or breastfeeding, or were taking medications that could have decreased their exposure to tecovirimat were assigned to receive open-label tecovirimat for 14 days. All other participants were randomized 2:1 to receive either tecovirimat or placebo for 14 days.

Randomized participants who reported severe pain 5 days after randomization (on Day 6) or later or progressed to severe disease stopped blinded study treatment and started a 14-day course of open-label tecovirimat.

Participants self-monitored lesions daily through 28 days (Day 29) or resolution, whichever came first, and completed a daily pain scale and symptom diary. Study visits occurred weekly through 28 days (Day 29) and included safety and skin assessments and specimen collections. A final study visit occurred at 56 days (Day 57) to assess for recrudescence of infection (development of new lesions after initial resolution of disease).

Version 3 of the protocol gave participants the option to enroll and complete study visits remotely. Participants did not provide specimens at remote visits.

On November 26, 2024, the Data and Safety Monitoring Board (DSMB) recommended that the study close due to statistical futility. The study team and sponsor agreed with the DSMB's recommendation and the study closed to accrual on November 27, 2024. The primary analysis report forming the basis of the primary manuscript used data from follow-up visits occurring through October 23, 2024, the data cutoff for the November 2024 DSMB review (the primary completion date). Outcome measures submitted to clinicaltrials.gov were also based on data from follow-up visits occurring through October 23, 2024, and summaries of participant flow, baseline characteristics, and adverse events submitted to clinicaltrials.gov were based on data from follow-up visits occurring through February 22, 2025 (the study completion date).

Conditions

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MPOX

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

DOUBLE

Participants Investigators

Study Groups

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Tecovirimat (Arm A)

Participants randomized to tecovirimat.

Group Type EXPERIMENTAL

Tecovirimat Oral Capsule

Intervention Type DRUG

* Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days
* Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days
* Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days

Placebo (Arm B)

Participants randomized to placebo.

Group Type PLACEBO_COMPARATOR

Placebo for Tecovirimat

Intervention Type DRUG

* Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days
* Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days
* Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days

Open-Label Tecovirimat (Arm C)

Participants assigned to open-label tecovirimat.

Group Type EXPERIMENTAL

Tecovirimat Oral Capsule (Open Label)

Intervention Type DRUG

* Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days
* Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days
* Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days
* Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days
* Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days
* Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days
* Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days

Interventions

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Tecovirimat Oral Capsule

Intervention Type DRUG

Placebo for Tecovirimat

Intervention Type DRUG

Tecovirimat Oral Capsule (Open Label)

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

1. Laboratory-confirmed or presumptive human mpox virus (HMPXV) infection.
2. HMPXV illness of \<14 days duration immediately prior to study entry.
3. At least one active (not yet scabbed) skin lesion, mouth lesion, or proctitis with or without visible ulcers.
4. Non-pregnant people of reproductive potential must agree to use at least one 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.
5. Ability to provide informed consent (for those above the legal age of consent and those providing consent for minors) and assent (for those who have reached the age of assent, but not the legal age of consent), as allowed by local ethics committees.
6. For participants to be enrolled/followed remotely, ability and willingness to participate in remote telehealth assessments (i.e., video visits).

1\. Age ≥18 years at the time of study entry.

Participants who meet the above entry criteria who also meet any of the following criteria will be registered to Arm C.

1. Age \<18 years at the time of study entry.
2. Those with severe HMPXV disease defined as having one or more of the following conditions:

* Suspected or confirmed ocular involvement
* Facial lesions on the malar, nose, or eyelid region
* Confluent facial lesions
* Hospitalization due to HMPXV infection or its complications
* Lesions that require surgical intervention including debridement, urinary catheterization or sigmoidoscopy, or lesions extending below the dermis.

Those with or without severe disease and with one or more of the following:

* Severe immunosuppression
* Active skin conditions placing the person at higher risk for disseminated infection
* Breastfeeding
* Pregnancy
* Receipt of potent inducers
* Current or planned use of another investigational drug at any point during tecovirimat/placebo dosing that would be predicted to have a significant drug-drug interaction with tecovirimat therapeutics.

Exclusion Criteria

1. Prior or concomitant receipt of tecovirimat (e.g., under an alternative access mechanism.
2. Planned initiation of intramuscular cabotegravir/rilpivirine during study drug administration or for two weeks following completion of study drug administration. Participants who were stable on long-acting intramuscular cabotegravir/rilpivirine were allowed to enroll.
3. Participants who, in the judgement of the investigator, will be at significantly increased risk as a result of participation in the study.
4. Participants who require intravenous dosing of tecovirimat.

Eligible Sex

ALL

Accepts Healthy Volunteers

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Timothy Wilkin, MD, MPH

Role: STUDY_CHAIR

Cornell

Locations

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Alabama CRS

Birmingham, Alabama, United States

Site Status

Kaiser Permanente Los Angeles Medical Center

Los Angeles, California, United States

Site Status

Los Angeles LGBT Center CRS

Los Angeles, California, United States

Site Status

UCLA CARE Center CRS

Los Angeles, California, United States

Site Status

University of California, Davis CRS

Sacramento, California, United States

Site Status

UCSD Antiviral Research Center CRS

San Diego, California, United States

Site Status

University of California, San Francisco HIV/AIDS CRS

San Francisco, California, United States

Site Status

Harbor University of California Los Angeles Center

Torrance, California, United States

Site Status

University of Colorado Denver NICHD CRS

Aurora, Colorado, United States

Site Status

University of Colorado Hospital CRS

Aurora, Colorado, United States

Site Status

Denver Public Health CRS

Denver, Colorado, United States

Site Status

University of Florida

Gainesville, Florida, United States

Site Status

University of Florida Jacksonville NICHD CRS

Jacksonville, Florida, United States

Site Status

University of Miami / Jackson Memorial Hospital

Miami, Florida, United States

Site Status

Univ. of South Florida (USF) College of Medicine A

Tampa, Florida, United States

Site Status

The Ponce de Leon Center CRS

Atlanta, Georgia, United States

Site Status

Rush University Cook County Hospital Chicago NICHD CRS

Chicago, Illinois, United States

Site Status

Johns Hopkins University CRS

Baltimore, Maryland, United States

Site Status

Massachusetts General Hospital CRS (MGH CRS)

Boston, Massachusetts, United States

Site Status

Brigham and Women's Hospital Therapeutics

Boston, Massachusetts, United States

Site Status

Henry Ford Hospital CRS

Detroit, Michigan, United States

Site Status

Washington University Therapeutics (WT) CRS

St Louis, Missouri, United States

Site Status