Study of Tecovirimat for Human Mpox Virus

Phase 3

Active, not recruiting

• Conditions: MPOX
• Interventions: Drug: Tecovirimat Oral Capsule; Drug: Placebo; Drug: Tecovirimat Oral Capsule (Open Label)

• Registration Number: NCT05534984
• Lead Sponsor: National Institute of Allergy and Infectious Diseases (NIAID)

Brief Summary

A5418 is a randomized, placebo-controlled, double-blind study to establish the efficacy of tecovirimat for the treatment of people with laboratory-confirmed or presumptive HMPXV disease.

Detailed Description

Eligible and consented participants for the randomized arms (N=530) will be randomized 2:1 to receive either tecovirimat or placebo; participants with severe disease, significant skin conditions, participants with severe immune suppression will receive open-label tecovirimat. Participants who are pregnant or breastfeeding will receive open-label tecovirimat after discussion of the potential risks and benefits. Participants less than 18 years of age will receive open-label tecovirimat. Participants receiving a potent inducing concomitant medication will receive open-label tecovirimat.

Once enrolled, study drug administration will be for 14 days. Participants who progress to severe HMPXV disease will be seen in person for a confirmation of progression. If severe disease is confirmed, participants will stop blinded study treatment and start a 14-day course of open-label tecovirimat. Participants reporting severe pain 5 days after randomization will stop blinded study treatment and start a 14-day course of open-label tecovirimat.

Participants will self-monitor skin and/or mucosal lesions daily through 29 days or resolution (whichever comes first), complete a daily diary of symptoms and complete a daily numerical rating scale for pain assessment.

Participants will be seen weekly through day 29 for assessment of HMPXV disease, safety assessments, HMPXV sampling similar to that described for entry, and swabbing of new HMPXV lesions.

Participants will be seen at day 57 to assess for possible recrudescence of infection (i.e., new lesions occurring after initial resolution of disease.

Study Timeline

• Study First Submitted: 2022-09-08
• Study First Submitted QC: 2022-09-08
• Study First Posted: 2022-09-10
• Study Start: 2022-09-12
• Primary Completion: 2024-10-23
• Status Verified: 2025-07
• Last Update Submitted: 2025-07-16
• Last Update Posted: 2025-07-20
• Study Completion: 2025-09-30

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 719

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Arm A	Tecovirimat Oral Capsule	-
Arm B	Placebo	-
Arm C	Tecovirimat Oral Capsule (Open Label)	-

Primary Outcome Measures

Name	Time	Method
Time to clinical resolution, defined as the first day on which all skin lesions are scabbed, desquamated or healed, and visible mucosal lesions are healed	Up to day 29

Secondary Outcome Measures

Name	Time	Method
Pain assessed by 11-point numerical rating scale for pain	Through day 29
Time to development of severe HMPXV in those without severe HMPXV at baseline	Through day 57
Level of HMPXV in blood	Through day 57
Level of HMPXV in skin lesions	Through day 57
Level of HMPXV in oropharynx	Through day 57
Level of HMPXV in rectum	Through day 57
Level of HMPXV in genital secretions	Through day 57
Time to complete lesion healing defined as all lesions being re-epithelialized	Up to day 29
Participant-reported adherence	Through day 15
Participant-reported quality-of-life as measured by EQ-5D-5L	Through day 29
Occurrence of Grade 3 or greater adverse event	Through day 57
All-cause mortality	Through day 57
Tecovirimat concentrations in blood in children less than 18 years of age	Through day 15

Trial Locations

Locations (54)

Alabama CRS; 🇺🇸 Birmingham, Alabama, United States

Kaiser Permanente Los Angeles Medical Center; 🇺🇸 Los Angeles, California, United States

Los Angeles LGBT Center CRS; 🇺🇸 Los Angeles, California, United States

UCLA CARE Center CRS; 🇺🇸 Los Angeles, California, United States

University of California, Davis CRS; 🇺🇸 Sacramento, California, United States

UCSD Antiviral Research Center CRS; 🇺🇸 San Diego, California, United States

University of California, San Francisco HIV/AIDS CRS; 🇺🇸 San Francisco, California, United States

Harbor University of California Los Angeles Center; 🇺🇸 Torrance, California, United States

University of Colorado Denver NICHD CRS; 🇺🇸 Aurora, Colorado, United States

University of Colorado Hospital CRS; 🇺🇸 Aurora, Colorado, United States

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