A Study of JNJ-64281802 for the Prevention of Dengue Infection

Number of participants with laboratory-confirmed symptomatic DENV infection between baseline and last day of dosing + 1 day among all HHC participants (with/without evidence of DENV infection at baseline) were reported. Laboratory confirmed symptomatic DENV infection was defined as having at least 2 solicited systemic adverse events (AEs; retro-orbital pain, fever, arthralgia, headache, myalgia, rash, abdominal pain, nausea, fatigue, loss of appetite, vomiting, and diarrhea) of which at least 1 was a most common dengue symptom (retro-orbital pain, fever, arthralgia, headache, myalgia, rash), lasted for >=1 day and occurred within +/-2 days time window around positive PCR or NS1 test, between baseline and last day of dosing. Sample was considered positive for DENV RNA when result was 'target detected' (when result was above the limit of detection of PCR assay) or sample considered DENV NS1 positive if qualitative DENV NS1 result was positive (quantitative DENV NS1 result >=11 RU/mL).

Number of participants with laboratory-confirmed symptomatic DENV infection between baseline and last day of dosing + 1 day among HHC participants with no evidence of DENV infection at baseline were reported. Laboratory confirmed symptomatic DENV infection was defined as having at least 2 solicited systemic AEs (retro-orbital pain, fever, arthralgia, headache, myalgia, rash, abdominal pain, nausea, fatigue, loss of appetite, vomiting, and diarrhea) of which at least 1 was a most common dengue symptom (retro-orbital pain, fever, arthralgia, headache, myalgia, and rash), lasted for >=1 day and occurred within a +/-2 days time window around the positive PCR or NS1 test, between baseline and the last day of dosing. A sample was considered positive for DENV RNA when the result was 'target detected' (when result was above the limit of detection of PCR assay) or sample was considered DENV NS1 positive if the qualitative DENV NS1 result was positive (quantitative DENV NS1 result >=11 RU/mL).

An adverse event (AE) was any untoward medical occurrence in a clinical study participant administered a medicinal (investigational or non-investigational) product. An AE does not necessarily have a causal relationship with the intervention. Serious AE was the AE resulting in any of following outcomes/deemed significant for any other reason: death; initial/prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. TEAEs were defined as any AE occurring at or after initial administration of study intervention until the last study-related activity, or until the participant had been deemed lost to follow-up after demonstration of due diligence of follow up efforts. TEAEs included both serious and non-serious adverse events.

Vital signs: pulse and blood pressure (systolic blood pressure[SBP]/diastolic blood pressure[DBP]). Abnormality grades determined per Division of Acquired Immunodeficiency Syndrome (DAIDS) for grading severity of adult and pediatric AEs: SBP(millimeters of mercury[mmHg]):Hypertension:Grade (G)1(mild):141-150, G2(moderate):greater than (>)150-155, G3(severe):>155; SBP(mmHg):Hypotension:G1(mild):85-89, G2(moderate):80 to less than (<)85, G3(severe):<80; DPB(mmHg):Hypertension:G1(mild):91-95, G2(moderate):>95-100, G3(severe):>100; Pulse(beats per minutes[bpm]):Tachycardia: G1(mild):>100-115, G2(moderate):>115-130, G3(severe):>130; Pulse(bpm):Bradycardia:G1(mild):50-54, G2(moderate):<50-45, G3(severe):<45. Any abnormality occurring at/after initial administration of study intervention until last study-related activity, or participant had been deemed lost to follow-up after demonstration of due diligence of follow up efforts was considered TE. Worst TE toxicity grade=highest grade reached.

ECG variables: heart rate (HR), PR interval, RR interval, QRS interval, QT interval, and corrected QT (QTc) interval using both following correction methods: QT corrected according to Bazett's formula (QTcB), QT corrected according to Fridericia's formula (QTcF). Abnormalities were categorized as low or high. HR (bpm): low: < 45, high: >=120; PR Interval (milliseconds [ms]): low: <110, high: >=220; QRS interval (ms): high: >=120; QTcB and QTcF (ms): Borderline prolonged QT: 450< QTc <=480, 480 <QTc <=500, QTc >500. Any abnormality occurring at or after initial administration of study intervention until last study-related activity, or participant had been deemed lost to follow-up after demonstration of due diligence of follow up efforts was considered treatment emergent.

Number of participants with treatment-emergent worst grade (Grade 3 or 4) abnormalities in laboratory parameters were reported. Laboratory assessments included clinical chemistry, hematology and urinalysis. Abnormality criterions were based on DAIDS: Grade 1= mild, Grade 2= moderate, Grade 3= severe, Grade 4= life-threatening. Any abnormality occurring at or after initial administration of study intervention until the last study-related activity, or until the participant had been deemed lost to follow-up after demonstration of due diligence of follow up efforts was considered treatment emergent.

Number of participants with abnormalities in physical examination parameters (head/neck/thyroid, eyes/ears/nose/throat, respiratory, cardiovascular, lymph nodes, abdomen, skin, musculoskeletal, and neurological) were reported based on investigator's discretion.

Plasma concentrations of JNJ-64281802 were reported. Plasma samples were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) method.