Conditions

Influenza Infection

Outcome Measures

Primary Outcomes (5)

Part 1: Infectivity Rate Based on Quantitative Reverse Transcriptase-Polymerase Chain Reaction (qRT-PCR) From Day 1 PM Through Day 8 AM
Infectivity rate was defined as the number of participants with two quantifiable (≥lower limit of quantitation (LLOQ)) influenza challenge virus (A/France/759/21 \[H1N1\] strain) qRT-PCR measurements reported on ≥2 independent nasopharyngeal samples (from nasal wash samples collected twice daily - morning and evening). Infectivity rate based on qRT-PCR in Part 1 participants from baseline (day 1 PM - afternoon) up to planned discharge from quarantine (day 8 AM - post viral inoculation) is presented. Per protocol, only data for part 1 participants were presented for this endpoint.
From Day 1 PM up to Day 8 post viral inoculation
Part 1: Infectivity Rate Based on Quantitative Reverse Transcriptase-Polymerase Chain Reaction (qRT-PCR) From Day 2 PM Through Day 8 AM
The number of participants with two quantifiable (≥lower limit of quantitation (LLOQ)) influenza challenge virus qRT-PCR measurements reported on ≥2 independent nasopharyngeal samples (from nasal wash samples collected twice daily - morning and evening). Infectivity rate based on qRT-PCR in Part 1 participants from day 2 PM up to day 8 post viral inoculation is presented. Per protocol, only data for part 1 participants were presented for this endpoint.
From Day 2 PM up to Day 8 post viral inoculation
Part 1: Number of Participants Experiencing ≥1 Viral Challenge-related Adverse Event (AE)
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE is viral challenge-related as determined by the investigator. Number of participants experiencing ≥1 viral challenge-related AE in part 1 is presented. Per protocol, only data for part 1 participants were presented for this endpoint.
Up to approximately 31 days
Part 2: Peak Viral Load (PVL) Determined by Quantitative Viral Culture Tissue Culture Infective Dose 50% (TCID50) Assay From Day 1 PM Through Day 8 AM After Intranasal Inoculation (Molnupiravir PEP and Placebo)
PVL was defined as the maximum viral load of influenza challenge virus from nasopharyngeal samples (nasal wash samples collected twice daily - morning and evening). PVL as determined by quantitative viral culture (QVC) was measured starting from day 1 PM (baseline) up to planned discharge from quarantine (day 8 AM). PVL of the H1N1 strain was measured by quantitative viral culture (QVC) using TCID50 plaque assay and analyzed using a linear model with treatment group as a fixed categorical effect. Per protocol, only data for Molnupiravir PEP and placebo were presented for this endpoint.
From Day 1 PM up to Day 8 post viral inoculation
Part 2: Area Under the Viral Load-Time Curve (VL-AUC) Determined by QVC (TCID50 Assay) From Day 2 AM Through Day 8 AM After Intranasal Inoculation (Molnupiravir Tx and Placebo)
VL-AUC is the area under the viral load-time curve of influenza challenge virus nasopharyngeal samples determined by QVC. H1N1 viral load was computed for each participant from nasopharyngeal samples collected twice daily (morning and evening) from day 2 AM to day 8 AM. VL-AUC (on the log10 scale) was analyzed using a linear model with treatment group as a fixed categorical effect. Per protocol, only data for Molnupiravir Tx and placebo were presented for this endpoint.
Days 2, 3, 4, 5, 6, 7 - twice daily (AM and PM), and day 8 AM post viral inoculation

Secondary Outcomes (79)

Part 1: QVC-Confirmed Influenza Infection From Day 1 PM Through Day 8 AM After Intranasal Inoculation
From Day 1 PM up to Day 8 post viral inoculation
Part 1: QVC-Confirmed Influenza Infection From Day 2 PM Through Day 8 AM After Intranasal Inoculation
From Day 2 PM Up to Day 8 post viral inoculation
Part 1: VL-AUC Determined by qRT-PCR From Day 1 PM Through Day 8 AM After Intranasal Inoculation
Day 1 PM, Days 2, 3, 4, 5, 6, 7 - twice daily (AM and PM), and day 8 AM post viral inoculation
Part 1: VL-AUC Determined by qRT-PCR From Day 2 PM Through Day 8 AM After Intranasal Inoculation
Day 2 PM, Days 3, 4, 5, 6, 7 - twice daily (AM and PM), and day 8 AM post viral inoculation
Part 1: VL-AUC Determined by Quantitative Viral Culture (TCID50 Assay) From Day 1 PM Through Day 8 AM After Intranasal Inoculation
Day 1 PM, Days 2, 3, 4, 5, 6, 7 - twice daily (AM and PM), and day 8 AM post viral inoculation

Study Arms (5)

Panel A: Molnupiravir Post-Exposure Prophylaxis (Part 2)

EXPERIMENTAL

Molnupiravir 800 mg every 12 hours Day 0 PM through Day 5 AM, placebo molnupiravir every 12 hours Day 5 PM through Day 6 PM

Drug: MolnupiravirDrug: Placebo molnupiravirBiological: Influenza A Virus

Panel B: Molnupiravir Treatment (Part 2)

EXPERIMENTAL

Placebo molnupiravir every 12 hours Day 0 PM through Day 1 PM, molnupiravir 800 mg every 12 hours Day 2 AM through Day 6 PM

Drug: MolnupiravirDrug: Placebo molnupiravirBiological: Influenza A Virus

Interventions

MolnupiravirDrug

Four molnupiravir 200 mg capsules (800 mg total dose) taken twice daily by mouth.

Also known as: MK-4482

Panel A: Molnupiravir Post-Exposure Prophylaxis (Part 2)Panel B: Molnupiravir Treatment (Part 2)

Placebo molnupiravirDrug

Four placebo capsules matched to molnupiravir taken twice daily by mouth.

Eligibility Criteria

Age18 Years - 55 Years

Sexall

Healthy VolunteersYes

Age GroupsAdult (18-64)

You may qualify if:

Is in good health based on medical history, physical examination, vital sign measurements, spirometry, and electrocardiograms performed before inoculation.
Has a total body weight ≥50 kg and Body Mass Index (BMI) ≥18 kg/m\^2 and ≤35 kg/m\^2.

Sponsors & Collaborators

Merck Sharp & Dohme LLC
Industrylead

Study Sites (1)

hVIVO Services ( Site 0001)

London, London, City of, E1 2AX, United Kingdom

Related Publications (1)

Schrell L, Scheibner D, Dickmanns A, Stegmann KM, Michaely LM, Graaf-Rau A, Beer P, Parker A, Diederich S, Balkema-Buschmann A, Dobbelstein M. Inhibitors of pyrimidine synthesis synergize with N4-hydroxycytidine to diminish influenza virus replication. Antiviral Res. 2025 Dec;244:106286. doi: 10.1016/j.antiviral.2025.106286. Epub 2025 Oct 3.
PMID: 41047107DERIVED

MeSH Terms

Interventions

molnupiravirOseltamivir

Intervention Hierarchy (Ancestors)

AcetamidesAmidesOrganic ChemicalsCyclohexenesCyclohexanesCycloparaffinsHydrocarbons, AlicyclicHydrocarbons, CyclicHydrocarbons

Results Point of Contact

Title: Senior Vice President, Global Clinical Development
Organization: Merck Sharp & Dohme LLC

Study Officials

Medical Director
Merck Sharp & Dohme LLC
STUDY DIRECTOR

Publication Agreements

PI is Sponsor Employee: No
Restriction Type: OTHER
Restrictive Agreement: Yes

Brief Summary

Registry Overview

Trial Relationships

Related Scientific Literature

Study Timeline

First Submitted

First Posted

Study Start

Primary Completion

Study Completion

Results Posted

Conditions

Outcome Measures

Primary Outcomes (5)

Secondary Outcomes (79)

Study Arms (5)

Panel A: Molnupiravir Post-Exposure Prophylaxis (Part 2)

Panel B: Molnupiravir Treatment (Part 2)

Interventions

Eligibility Criteria

You may qualify if:

Sponsors & Collaborators

Study Sites (1)

Related Publications (1)

Related Links

MeSH Terms

Interventions

Intervention Hierarchy (Ancestors)

Results Point of Contact

Study Officials

Publication Agreements

Enrollment

Study Design

Study Record Dates

Panel C: Oseltamivir Treatment (Part 2)

Panel D: Molnupiravir Placebo (Part 2)

Virus Inoculation (Part 1 & 2)

You may not qualify if:

Data Sharing

Source record

Documents

Locations