NCT05559905

Respiratory Syncytial Virus (RSV) Human Challenge Study of Molnupiravir in Healthy Participants (MK-4482-017)

A Phase 2a Double-Blind, Randomized, Placebo-Controlled Study to Evaluate the Efficacy and Safety of MK-4482 in Healthy Participants Inoculated With Experimental Respiratory Syncytial Virus

• Status: Completed
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 116 (actual)
• Sponsor: Merck Sharp & Dohme LLC · Industry
• Sex: All
• Age: 18 Years – 55 Years
• Healthy volunteers: Accepted

Summary

This is a study of molnupiravir (MK-4482) in healthy participants who have been inoculated with an experimental Respiratory Syncytial Virus (RSV) \[RSV-A Memphis 37b\]. It is hypothesized that treatment with the drug MK-4482 (molnupiravir) will reduce the peak viral load (PVL) in the participant compared to placebo when given either before or after RSV-A Memphis 37b inoculation.

Detailed description

Participants arrive at the study center for check-in between Day -3 and Day -1. Participants receive the assigned treatment beginning on Day -1. On Day 0, all participants receive viral inoculation with RSV-A Memphis 37b. All participants depart on Day 12 and follow-up is continued until Day 28. The study is designed with the following arms: * Panel A: Molupiravir Prophylaxis - in this arm, participants receive molupiravir beginning on Day -1, are incoluated with RSV-A Memphis 37b on Day 0, and continue receiving molnupiravir for a total of 5 days before switching to placebo through Day 10. * Panel B: Molupiravir Triggered Treatment - in this arm, participants receive placebo beginning on Day -1 until testing positive for RSV. Participants are inoculated with RSV-A Memphis 37b on Day 0. When participants test positive for RSV, they switch to molnupiravir for a total of 5 consecutive days before switching back to placebo through Day 10. If participants in this arm do not test positive for RSV by Day 5, they automatically switch to molnupiravir through Day 10. * Panel C: Placebo - in this arm, all participants receive placebo beginning on Day -1, are inoculated with RSV-A Memphis 37b on Day 0, and continue receiving placebo through Day 10.

Conditions

• Respiratory Syncytial Virus

Interventions

Type	Name	Description
DRUG	Molnupiravir	Four molnupiravir 200 mg capsules (800 mg total dose) taken twice daily by mouth.
DRUG	Placebo	Placebo capsule matched to molnupiravir taken twice daily by mouth.
BIOLOGICAL	RSV A Memphis 37b	RSV A Memphis 37b viral challenge given once by intranasal administration at a dosage of \~4 Log10 plaque forming units (PFUs).

Timeline

• Start date: 2022-11-02
• Primary completion: 2023-04-18
• Completion: 2023-06-08
• First posted: 2022-09-29
• Last updated: 2025-07-18
• Results posted: 2024-05-20

Locations

1 site across 1 country: United Kingdom

Regulatory

• FDA-regulated drug study