JNJ-53718678

Area under the RSV VL-time curve (AUC) was determined as log10 copies\*hour per milliliter (Log10 copies\*hr/mL) by quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay of mid turbine nasal swabs.

Area under the RSV VL-time curve (AUC) was determined as Log10 copies\*hr/mL by qRT-PCR assay of mid turbine nasal swabs.

Area under the RSV VL-time curve (AUC) was determined as Log10 copies\*hr/mL by qRT-PCR assay of mid turbine nasal swabs.

Area under the RSV VL-time curve (AUC) was determined as Log10 copies\*hr/mL by qRT-PCR assay of mid turbine nasal swabs.

Change from baseline in RSV viral load at Day 3 was measured as Log10 copies/mL by qRT-PCR assay in the mid-turbinate nasal swab specimens.

Change from baseline in RSV viral load at Day 5 was measured as Log10 copies/mL by qRT-PCR assay in the mid-turbinate nasal swab specimens.

Change from baseline in RSV viral load at Day 8 was measured as Log10 copies/mL by qRT-PCR assay in the mid-turbinate nasal swab specimens.

Change from baseline in RSV viral load at Day 14 was measured as Log10 copies/mL by qRT-PCR assay in the mid-turbinate nasal swab specimens.

Change from baseline in RSV viral load oat Day 21 was measured as Log10 copies/mL by qRT-PCR assay in the mid-turbinate nasal swab specimens.

RSV viral load was measured as log10 copies/mL by qRT-PCR assay in the mid-turbinate nasal swab specimens.

RSV viral load was measured as log10 copies/mL by qRT-PCR assay in the mid-turbinate nasal swab specimens.

RSV viral load was measured as log10 copies/mL by qRT-PCR assay in the mid-turbinate nasal swab specimens.

RSV viral load was measured as log10 copies/mL by qRT-PCR assay in the mid-turbinate nasal swab specimens.

RSV viral load was measured as log10 copies/mL by qRT-PCR assay in the mid-turbinate nasal swab specimens.

RSV viral load was measured as log10 copies/mL by qRT-PCR assay in the mid-turbinate nasal swab specimens.

The time to undetectable nasal RSV RNA viral load was defined as the time in days from initiation of study treatment until first post-baseline time point at which RSV RNA was undetectable and after which time there were no more detectable virus assessments.

Percentage of participants with undetectable RSV viral load at Day 3 were reported.

Percentage of participants with undetectable RSV viral load at Day 5 were reported.

Percentage of participants with undetectable RSV viral load at Day 8 were reported.

Percentage of participants with undetectable RSV viral load at Day 14 were reported.

Percentage of participants with undetectable RSV viral load at Day 21 were reported.

VL AUC for RSV-A Memphis 37b will be determined by quantitative reverse transcriptase -polymerase chain reaction (qRT-PCR) assay of nasal wash. The VL AUC will be calculated based on the viral load values measured 2 times per day, starting with the last value prior to first dosing, and ending with the last available value before discharge.

Ctrough is defined as observed plasma analyte concentration just prior to the beginning of a dosing interval.

Ctrough is defined as observed plasma analyte concentration just prior to the beginning of a dosing interval.

Cmax is defined as maximum observed plasma analyte concentration.

Cmax is defined as maximum observed plasma analyte concentration.

AUC24h is defined as AUC from time 0 to 24 hours postdose.

AUC24h is defined as AUC from time 0 to 24 hours postdose.

Placebo-corrected change from baseline in QT interval corrected for heart rate (QTc) will be determined. The mean change from baseline in QTc in placebo treatment will be subtracted from the mean change from baseline in JNJ-53718678 treatment at the same time point to generate placebo-corrected change from baseline in QTc, which will be presented.

Total mass balance calculated by D(dose) urine, total (percent \[%\]) + D feces, total (%) + D duodenal, total (%) where D urine, total is the total percentage of the dose excreted into urine, calculated as 100 \* (Ae total \[total amount excreted into urine, calculated by adding the amounts of the individual intervals together\] /Dose); D feces,total is the total percentage of the dose excreted into feces, calculated as 100 \* (Ae total \[total amount excreted into feces, calculated by adding the amounts of the individual stools together\]/Dose) and D duodenal, total is defined as total percentage of the dose collected in all duodenal samples collectively, calculated as % of dose.

Metabolite profiling will be performed with radio high-performance liquid chromatography.

The Cmax is the maximum observed plasma concentration.

The AUC (0-last) is the area under the plasma concentration time curve from time 0 to the time of the last measurable non-below quantification limit concentration, calculated by liner-linear trapezoidal summation.

The AUC (0-infinity) is the area under the plasma concentration time curve from time zero to infinite time, calculated as the sum of AUC(last) and C(last)/lambda(z); wherein AUC(last) is area under the plasma concentration time curve from time zero to last quantifiable time, C(last) is the last observed quantifiable concentration, and lambda(z) is elimination rate constant.

The relative bioavailability based on Cmax, AUC(0last), and AUC(0-inf) will be estimated as 100\*Test/Reference, where Test is defined as the pharmacokinetic parameters of oral JNJ-53718678 and Reference is defined as currently existing oral solution G024.

The effect of food will be evaluated by comparing the pharmacokinetics of JNJ-53718678 under fed conditions with the currently existing oral solution under fasted conditions.

The Cmax is the maximum observed analyte concentration after the JNJ-53718678 doses on Day 1, Day 4 (Panel 2 only) and Day 9.

The (AUC \[0-last\]) is the area under the analyte concentration-time curve from time 0 to time of the last quantifiable concentration after the JNJ-53718678 doses on Day 1 and Day 9.

The AUC (0-infinity) is the area under the Analyte concentration-time curve from time 0 to infinite time after the JNJ-53718678 doses on Day 1 and Day 9, calculated as the sum of AUC(0-last) and C(0-last)/lambda(z), wherein AUC(0-last) is the area under the analyte concentration-time curve from time 0 to time of the last quantifiable concentrations; C(0-last) is the last observed quantifiable concentration; and lambda(z) is elimination rate constant.

The AUC24h is the area under the analyte concentration-time curve from time 0 to 24h after dosing on Day 1 and Day 4 (Panel 2 only).

Ratio Cmax, test/reference is the ratio of individual Cmax values between test (JNJ-53718678 with itraconazole, on Day 9, or JNJ-53718678 with rifampicin, on Day 4 and Day 9) and reference (without itraconazole or rifampicin, on Day 1) treatments.

Ratio AUC24h, test/reference is the ratio of individual AUC24h values between test (JNJ-53718678 with rifampicin, on Day 4) and reference (without rifampicin, on Day 1) treatments.

Ratio AUClast, test/reference is the ratio of individual AUClast values between test (JNJ-53718678 with itraconazole or rifampicin, on Day 9) and reference (without itraconazole or rifampicin, on Day 1) treatments.

Ratio AUC(infinity), test/reference is the ratio of individual AUC(infinity) values between test (JNJ-53718678 with itraconazole or rifampicin, on Day 9) and reference (without itraconazole or rifampicin, on Day 1) treatments.

The Cmax is the maximum observed plasma concentration.

The Tmax is defined as actual sampling time to reach maximum observed JNJ 53718678 concentration.

The Tlast is the time to last observed quantifiable plasma concentration.

The AUC (0-last) is the area under the plasma concentration-time curve from time zero to last quantifiable time.

The AUC (0-infinity) is the area under the plasma concentration-time curve from time zero to infinite time, calculated as the sum of AUC(last) and C(last)/lambda(z); wherein AUC(last) is area under the plasma concentration-time curve from time zero to last quantifiable time, C(last) is the last observed quantifiable concentration, and lambda(z) is elimination rate constant.

Apparent initial elimination rate constant, determined by linear regression of the data points within the first elimination phase of the ln-linear plasma concentration-time curve.

Lambda(z) is first-order elimination rate constant associated with the terminal portion of the curve, determined as the negative slope of the terminal log-linear phase of the drug concentration-time curve.

Apparent initial elimination half-life is calculated as 0.693/lambda(alpha).

The elimination half-life (t1/2) is the time measured for the plasma concentration to decrease by 1 half to its original concentration. It is associated with the terminal slope of the semi logarithmic drug concentration-time curve, and is calculated as 0.693/lambda(z).

Clearance of a drug is a measure of the rate at which a drug is metabolized or eliminated by normal biological processes. Clearance obtained after oral dose (apparent oral clearance) is influenced by the fraction of the dose absorbed. Drug clearance is a quantitative measure of the rate at which a drug substance is removed from the blood.

Volume of distribution is defined as the theoretical volume in which the total amount of drug would need to be uniformly distributed to produce the desired plasma concentration of a drug. Apparent volume of distribution after subcutaneous dose (Vd/F) is influenced by the fraction absorbed.

An adverse event is any untoward medical event that occurs in a participant administered an investigational product, and it does not necessarily indicate only events with clear causal relationship with the relevant investigational product.