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MPOXPhase 3STOMPNCT05534984

Study of Tecovirimat for Human Mpox Virus

A Phase 3 study testing Tecovirimat Oral Capsule and Tecovirimat Oral Capsule (Open Label) in people with MPOX, run by National Institute of Allergy and Infectious Diseases (NIAID) at 54 sites in 6 countries.

Terminated

Stopped early. The study ended before it was planned to and will not resume.

Official record
Search all trials

Trial summary

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). Read more about this study

Who is it for?
Any age
Conditions the study is for
MPOX
What is being tested?
Tecovirimat Oral Capsule and Tecovirimat Oral Capsule (Open Label)
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
719 participants
Where
54 sitesin 6 countries
Study dates
8 Sep 2022to 22 Feb 2025
Phase
Phase 3
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages Any age
  • All sexes
  • No healthy volunteers
  • Child, Adult, Older adult

Who may be able to join

  • Laboratory-confirmed or presumptive human mpox virus (HMPXV) infection.
  • HMPXV illness of <14 days duration immediately prior to study entry.
  • At least one active (not yet scabbed) skin lesion, mouth lesion, or proctitis with or without visible ulcers.
  • 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.
  • 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.
  • For participants to be enrolled/followed remotely, ability and willingness to participate in remote telehealth assessments (i.e., video visits).
Show all 24Show fewer
  • Additional Inclusion Criteria for Arms A and B:
  • 1. Age ≥18 years at the time of study entry.
  • Additional Inclusion Criteria for Arm C:
  • Participants who meet the above entry criteria who also meet any of the following criteria will be registered to Arm C.
  • Age <18 years at the time of study entry.
  • 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.

Who cannot join

  • Prior or concomitant receipt of tecovirimat (e.g., under an alternative access mechanism.
  • 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.
  • Participants who, in the judgement of the investigator, will be at significantly increased risk as a result of participation in the study.
  • Participants who require intravenous dosing of tecovirimat.

Trial locations and contacts

54 sites in 6 countries.

54 sites in 6 countries

United States44 sites

  • The Ponce de Leon Center CRS

    Atlanta, Georgia, 30308

  • University of Colorado Denver NICHD CRS

    Aurora, Colorado, 80045

  • University of Colorado Hospital CRS

    Aurora, Colorado, 80045

  • Johns Hopkins University CRS

    Baltimore, Maryland, 21205

  • Alabama CRS

    Birmingham, Alabama, 35294

  • Massachusetts General Hospital CRS (MGH CRS)

    Boston, Massachusetts, 02114

  • Brigham and Women's Hospital Therapeutics

    Boston, Massachusetts, 02115

  • Rush University Cook County Hospital Chicago NICHD CRS

    Chicago, Illinois, 60612

  • Cincinnati CRS

    Cincinnati, Ohio, 45267

  • Case Western Reserve University CTU

    Cleveland, Ohio, 44106

  • Ohio State University CRS

    Columbus, Ohio, 43210

  • North Texas Infectious Disease Consultants

    Dallas, Texas, 75246

  • UT Southwestern Infectious Disease Research Unit

    Dallas, Texas, 75390

  • Denver Public Health CRS

    Denver, Colorado, 80204

  • Henry Ford Hospital CRS

    Detroit, Michigan, 48202

  • Duke University Medical Center CRS

    Durham, North Carolina, 27710

  • University of Florida

    Gainesville, Florida, 32610

  • Houston AIDS Research Team (HART) CRS

    Houston, Texas, 77030

  • University of Florida Jacksonville NICHD CRS

    Jacksonville, Florida, 32209

  • Kaiser Permanente Los Angeles Medical Center

    Los Angeles, California, 90027

  • Los Angeles LGBT Center CRS

    Los Angeles, California, 90028

  • UCLA CARE Center CRS

    Los Angeles, California, 90035

  • St. Jude Children's Research Hospital ATN CRS

    Memphis, Tennessee, 38105

  • University of Miami / Jackson Memorial Hospital

    Miami, Florida, 33136

  • Weill Cornell Chelsea CRS

    New York, New York, 10010

  • Mount Sinai West Samuels CRS

    New York, New York, 10019

  • Harlem Prevention Center

    New York, New York, 10027

  • Columbia Physicians & Surgeons (P&S) CRS

    New York, New York, 10032

  • Weill Cornell Uptown CRS

    New York, New York, 10065

  • Bronx-Lebanon Hospital Center NICHD CRS

    New York, New York, 10457

  • Infectious Disease Clinical and Translational Research

    New York, New York, 11029

  • New Jersey Medical School Clinical Research Center

    Newark, New Jersey, 07103

  • Penn Therapeutics CRS

    Philadelphia, Pennsylvania, 19104

  • University of Pittsburgh CRS

    Pittsburgh, Pennsylvania, 15213

  • University of Rochester Adult HIV Therapeutic

    Rochester, New York, 14642

  • University of California, Davis CRS

    Sacramento, California, 95817

  • UCSD Antiviral Research Center CRS

    San Diego, California, 92103

  • University of California, San Francisco HIV/AIDS CRS

    San Francisco, California, 94110

  • University of Washington Positive Research

    Seattle, Washington, 98104

  • Washington University Therapeutics (WT) CRS

    St Louis, Missouri, 63110

  • SUNY Stony Brook NICHD CRS

    Stony Brook, New York, 11794

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

    Tampa, Florida, 33606

  • Harbor University of California Los Angeles Center

    Torrance, California, 90502

  • Wake Forest Baptist Medical Center CRS

    Winston-Salem, North Carolina, 27157

Other trials in United States

Peru5 sites

  • Centro de Investigaciones Tecnológicas, Biomédicas y Medioambientales CRS (CITBM) - Unidad de Ensayos Clínicos (UNIDEC) CRS

    Callao

  • Barranco CRS

    Lima

  • San Miguel CRS

    Lima

  • Socios En Salud Sucursal Peru

    Lima

  • Via Libre CRS

    Lima

Other trials in Peru

Thailand2 sites

  • Thai Red Cross AIDS Research Centre

    Bangkok

  • Vaccine Trial Centre, Mahidol University CRS

    Bangkok

Other trials in Thailand

Argentina1 site

  • Fundacion Huesped CRS

    Buenos Aires

Other trials in Argentina

Brazil1 site

  • Centro de Pesquisas Clínicas IC-HCFMUSP CRS

    São Paulo

Other trials in Brazil

Mexico1 site

  • Nutricion Mexico CRS

    Mexico City

Other trials in Mexico

About this study

Official title: A Randomized, Placebo-Controlled, Double-Blinded Trial of the Safety and Efficacy of Tecovirimat for the Treatment of Human Mpox Virus Disease

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).

Read the detailed description

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
MPOX
Being tested
Tecovirimat Oral Capsule, Placebo for Tecovirimat, Tecovirimat Oral Capsule (Open Label)
Keywords
HMPXV
Medical subject headings
Mpox, Monkeypox

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Tecovirimat Oral CapsuleDrug

    • 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 for TecovirimatDrug

    • 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

  • Tecovirimat Oral Capsule (Open Label)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
Study groups in NCT05534984
Study groupRoleWhat they receive
Tecovirimat (Arm A)ExperimentalParticipants randomized to tecovirimat.
Receives: Drug: Tecovirimat Oral Capsule
Placebo (Arm B)Placebo comparatorParticipants randomized to placebo.
Receives: Drug: Placebo for Tecovirimat
Open-Label Tecovirimat (Arm C)ExperimentalParticipants assigned to open-label tecovirimat.
Receives: Drug: Tecovirimat Oral Capsule (Open Label)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Cumulative Proportion With Clinical Resolution by Day 29

    Clinical resolution defined as all skin lesions scabbed, desquamated, or healed, and visible mucosal lesions healed. The cumulative proportion with clinical resolution was estimated using the Aalen-Johansen estimator. The treatment effect, i.e., the subdistribution hazard ratio of tecovirimat relative to placebo, was estimated using the Fine and Gray subdistribution proportional hazards model. All-cause death, start of open-label tecovirimat due to disease progression or severe pain, and use of other antivirals with expected activity against mpox were treated as competing events. Follow-up time was censored at last contact. Includes data from follow-up visits occurring through October 23, 2024.

    Measured: From study entry through 28 days of follow-up (i.e., Day 29)

Secondary outcomes (19)

  1. Mean Time-weighted Average of Pain Intensity Difference Over 5 Days of Treatment

    Pain was measured on 11-point numerical rating scale (NRS) where 0 = no pain and 10 = worst possible pain.

    Pain intensity difference at ith day of treatment (i = 2, ..., 6) calculated as NRS pain score at baseline (last available pre-treatment) minus NRS pain score on ith day of treatment

    Time-weighted average of pain intensity difference over 5 days of treatment was a weighted average of the pain intensity difference from treatment day 2 to treatment day 6, where the weights were calculated as the duration in days between the ith day of treatment and the day of the previous measurement. The lowest possible value that this could have been was -10, which would have indicated an increase in pain by 10 points on average over 5 days of treatment. The highest possible value that this could have been was +10, which would have indicated a decrease in pain by 10 points on average over 5 days of treatment.

    Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Through 5 days of treatment (i.e., Treatment Day 6)

  2. Mean Time-weighted Average of Pain Intensity Difference Over 14 Days of Treatment

    Pain was measured on 11-point numerical rating scale (NRS) where 0 = no pain and 10 = worst possible pain.

    Pain intensity difference at ith day of treatment (i = 2, ..., 15) calculated as NRS pain score at baseline (last available pre-treatment) minus NRS pain score on ith day of treatment

    Time-weighted average of pain intensity difference over 14 days of treatment was a weighted average of the pain intensity difference from treatment day 2 to treatment day 15, where the weights were calculated as the duration in days between the ith day of treatment and the day of the previous measurement. The lowest possible value that this could have been was -10, which would have indicated an increase in pain by 10 points on average over 5 days of treatment. The highest possible value that this could have been was +10, which would have indicated a decrease in pain by 10 points on average over 5 days of treatment.

    Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Through 14 days of treatment (i.e., Treatment Day 15)

  3. Number of Participants Who Developed Severe HMPXV Disease

    Severe HMPXV disease was defined as 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, or lesions that required surgical intervention including debridement, urinary catheterization, or sigmoidoscopy, or extended below the dermis.

    Measured: From study entry through 56 days of follow-up (i.e., Day 57)

  4. Number of Participants With HMPXV DNA Below Limit of Detection in Skin Lesions

    HMPXV DNA was measured as detected or below limit of detection. Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Baseline, Days 8, 15, 22, 29, and 57

  5. Number of Participants With HMPXV DNA Below Limit of Detection in Oropharynx

    HMPXV DNA was measured as detected or below limit of detection. Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Baseline, Days 8, 15, 22, 29, and 57

  6. Number of Participants With HMPXV DNA Below Limit of Detection in Rectum

    HMPXV DNA was measured as detected or below limit of detection. Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Baseline, Days 8, 15, 22, 29, and 57

  7. Number of Participants With HMPXV DNA Below Limit of Detection in Blood

    HMPXV DNA measured as detected or below limit of detection. Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Baseline, Days 8, 15, 22, 29, and 57

  8. Number of Participants With HMPXV DNA Below Limit of Detection in Vaginal Swabs

    HMPXV DNA measured as detected or below limit of detection. Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Baseline, Days 8, 15, 22, 29, and 57

  9. Cumulative Proportion With Complete Lesion Healing by Day 29

    Complete lesion healing was defined as all lesions re-epithelialized. The cumulative incidence of complete lesion healing was estimated using the Aalen-Johansen estimator. The treatment effect, i.e., the subdistribution hazard ratio of tecovirimat relative to placebo, was estimated using the Fine and Gray subdistribution proportional hazards model. All-cause death, start of open-label tecovirimat due to disease progression or severe pain, and use of other antivirals with expected activity against mpox were treated as competing events. Follow-up time was censored at last contact. Includes data from follow-up visits occurring through October 23, 2024.

    Measured: From study entry through 28 days of follow-up (i.e., Day 29)

  10. Number of Participants With no Missed Doses (of Last Three Prescribed Doses)

    Since the adherence assessment was removed from protocol version 3.0, the number of participants with adherence data was expected to be small and no formal statistical comparison between treatment arms was done. Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Days 8 and 15

  11. Median Change From Baseline in EuroQol (EQ) Visual Analogue Scale (VAS) Score

    Participants' self-rated health measured on a visual analogue scale (VAS) where 0 = "The worst health you can imagine" and 100 = "The best health you can imagine." Change in EQ VAS score at each timepoint calculated as absolute change from baseline (last available pre-treatment). Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Days 8, 15, and 29

  12. Number of Participants Who Reported Each Level of Response on Mobility Dimension of EuroQol EQ-5D-5L Questionnaire

    Participants' self-reported health state within mobility dimension of the five-dimension EuroQol EQ-5D-5L questionnaire. Participants were asked to indicate their health state by selecting the most appropriate response level for them from five ordinal response levels: no problems (1), slight problems (2), moderate problems (3), severe problems (4), and extreme problems (5).

    Results were dichotomized into no problems (level 1) and any problems (levels 2, 3, 4, and 5 combined) for reporting and analysis.

    Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Baseline, Days 8, 15, and 29

  13. Number of Participants Who Reported Each Level of Response on Self-Care Dimension of EuroQol EQ-5D-5L Questionnaire

    Participants' self-reported health state within self-care dimension of five-dimension EuroQol EQ-5D-5L questionnaire. Participants were asked to indicate their health state by selecting the most appropriate response level for them from five ordinal response levels: no problems (1), slight problems (2), moderate problems (3), severe problems (4), and extreme problems (5).

    Results were dichotomized into no problems (level 1) and any problems (levels 2, 3, 4, and 5 combined) for reporting and analysis.

    Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Baseline, Days 8, 15, and 29

  14. Number of Participants Who Reported Each Level of Response on Usual Activities Dimension of EuroQol EQ-5D-5L Questionnaire

    Participants' self-reported health state within usual activities dimension of five-dimension EuroQol EQ-5D-5L questionnaire. Participants were asked to indicate their health state by selecting the most appropriate response level for them from five ordinal response levels: no problems (1), slight problems (2), moderate problems (3), severe problems (4), and extreme problems (5).

    Results were dichotomized into no problems (level 1) and any problems (levels 2, 3, 4, and 5 combined) for reporting and analysis.

    Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Baseline, Days 8, 15, and 29

  15. Number of Participants Who Reported Each Level of Response on Pain/Discomfort Dimension of EuroQol EQ-5D-5L Questionnaire

    Participants' self-reported health state within pain/discomfort dimension of five-dimension EuroQol EQ-5D-5L questionnaire. Participants were asked to indicate their health state by selecting the most appropriate response level for them from five ordinal response levels: no problems (1), slight problems (2), moderate problems (3), severe problems (4), and extreme problems (5).

    Results were dichotomized into no problems (level 1) and any problems (levels 2, 3, 4, and 5 combined) for reporting and analysis.

    Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Baseline, Days 8, 15, and 29

  16. Number of Participants Who Reported Each Level of Response on Anxiety/Depression Dimension of EuroQol EQ-5D-5L Questionnaire

    Participants' self-reported health state within anxiety/depression dimension of five-dimension EuroQol EQ-5D-5L questionnaire. Participants were asked to indicate their health state by selecting the most appropriate response level for them from five ordinal response levels: no problems (1), slight problems (2), moderate problems (3), severe problems (4), and extreme problems (5).

    Results were dichotomized into no problems (level 1) and any problems (levels 2, 3, 4, and 5 combined) for reporting and analysis.

    Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Baseline, Days 8, 15, and 29

  17. Proportion of Participants With Grade 3 or Greater Treatment-emergent Adverse Event

    Study protocol required reporting of all adverse events (AEs) that (1) led to a change in study treatment regardless of grade, (2) met the serious AE (SAE) or Expedited AE (EAE) reporting requirement, and (3) were Grade 3 or greater. AEs were graded using the DAIDS AE Grading Table (Version 2.1).

    Severity Grade: 1 = Mild, 2 = Moderate, 3 = Severe, 4 = Life-Threatening, 5 = Death

    Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Through 56 days of follow-up (i.e., Day 57)

  18. Number of Participants Who Died From Any Cause

    Includes data from follow-up visits occurring through October 23, 2024.

    Measured: Through 56 days of follow-up (i.e., Day 57)

  19. Tecovirimat Concentrations in Children Less Than 18 Years of Age

    Plasma tecovirimat concentrations were quantified using validated liquid chromatography tandem mass spectrometry (LC-MS/MS) methods. The lower limit of quantification was 5.0 ng/mL.

    Measured: On Day 8, blood samples were collected pre-dose and at 1, 2, 3, 4, 6, 8, and 10 hours post-dose. On Day 15, a single blood sample was collected within 4 hours of study product administration.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted10 Sep 2022
  2. Study start8 Sep 2022
  3. Primary completion23 Oct 2024
  4. Study completion22 Feb 2025

Why it stopped: DSMB recommendation due to statistical futility

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Double blind
Who is masked
Participant, Investigator
Enrolment
719 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05534984
Sponsor's protocol ID
A5418
Other IDs
38982
Acronym
STOMP
Status last verified
May 2026
First submitted
8 Sep 2022
Last updated
23 Jun 2026
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: Individual participant data that underlie results in the publication after deidentification

Publications

  • Zucker J, Fischer WA 2nd, Zheng L, McCarthy C, Saha PT, Javan AC, Greninger A, Hamill MM, Leslie K, Brooks KM, Berardi J, Smith D, Hosey L, Aldrovandi G, Ferbas K, Day C, Bender Ignacio RA, Bolan R, Glesby MJ, Landovitz RJ, Luetkemeyer AF, Sierra Madero J, Gandhi RT, Nachman S, Eron J, Currier JS, Wilkin T; STOMP/A5418 Investigators. Tecovirimat for the Treatment of Mpox. N Engl J Med. 2026 Feb 26;394(9):884-895. doi: 10.1056/NEJMoa2506495.

    PubMed 41740032

  • Chenchula S, Atal S, Ghanta MK, Uppugunduri CR, Karunakaran S, Amerneni KC, Sarma P, Prakash S, Amerneni LS, Padmavathi R, Anitha K, Sri Varshini T, Vishnu Vardhan K, Kaore S, Sadasivam B. Emerging variants of Mpox virus and tecovirimat resistance: Genomic insights and implications for treatment strategies. Virology. 2025 Jul;608:110532. doi: 10.1016/j.virol.2025.110532. Epub 2025 Apr 12.

    PubMed 40245474

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing Tecovirimat Oral Capsule and Tecovirimat Oral Capsule (Open Label) in people with MPOX, run by National Institute of Allergy and Infectious Diseases (NIAID) at 54 sites in 6 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 24 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: stopped early, as of the sponsor's last update on 23 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 54 sites in United States, Peru, Thailand, Argentina, Brazil and 1 more country. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 10 Feb 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Cumulative Proportion With Clinical Resolution by Day 29 (time frame: From study entry through 28 days of follow-up (i.e., Day 29)). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05534984, which also lists 2 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Jun 2026.

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