Antiviral activity of oral JNJ-53718678 in healthy adult volunteers challenged with respiratory syncytial virus: A placebo-controlled study

Abstract

Background. Respiratory syncytial virus (RSV) disease has no effective treatment. JNJ-53718678 is a fusion inhibitor with selective activity against RSV. Methods. After confirmation of RSV infection or 5 days after inoculation with RSV, participants (n = 69) were randomized to JNJ-53718678 75 mg (n = 15), 200 mg (n = 17), 500 mg (n = 18), or placebo (n = 17) orally once daily for 7 days. Antiviral effects were evaluated by assessing RSV RNA viral load (VL) area under the curve (AUC) from baseline (before the first dose) until discharge, time-to-peak VL, duration of viral shedding, clinical symptoms, and quantity of nasal secretions. Results. Mean VL AUC was lower for individuals treated with different doses of JNJ-53718678 versus placebo (203.8-253.8 vs 432.8 log10 PFUe.hour/mL). Also, mean peak VL, time to peak VL, duration of viral shedding, mean overall symptom score, and nasal secretion weight were lower in each JNJ-53718678-treated group versus placebo. No clear exposure-response relationship was observed. Three participants discontinued due to treatment-emergent adverse events of grade 2 and 1 electrocardiogram change (JNJ-53718678 75 mg and 200 mg, respectively) and grade 2 urticaria (placebo). Conclusions. JNJ-53718678 at all 3 doses substantially reduced VL and clinical disease severity, thus establishing clinical proof of concept and the compound's potential as a novel RSV treatment.