Efficacy and Safety of Molnupiravir in Healthy Participants Inoculated With Experimental Influenza Virus (MK-4482-019)

Summary

This is a phase 2a double-blind, randomized, placebo-controlled study to evaluate the efficacy and safety of molnupiravir (MK-4482) in healthy participants inoculated with experimental influenza virus. The primary hypotheses are that MK-4482 initiated 12 hours following intranasal inoculation of the influenza challenge virus reduces the peak viral load compared to placebo and that MK-4482 initiated 2 days following intranasal inoculation of the influenza challenge virus reduces the viral load area under the curve (AUC) compared to placebo.

Timeline

Start

2023-08-21

Primary completion

2024-06-28

Completion

2024-06-28

Outcome

Missed primary endpoint

registry Molnupiravir Post-Exposure Prophylaxis (PEP) vs Placebo; p = 0.110; Difference in least squares means -0.94 (95% CI -2.10 to 0.22); ANOVA NCT05818124 ↗

registry Molnupiravir Treatment (Tx) vs Placebo; p = 0.090; Difference in least squares mean -1.60 (95% CI -3.47 to 0.27); ANOVA NCT05818124 ↗

Publications

• 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.

Drugs

Evaluation	Drug	Modality	Dose	Route
Subject	Molnupiravir	Small molecule	800 mg	Oral
Comparator	Oseltamivir	Small molecule	75 mg	Oral

Indications