An Exploratory, Phase 2a, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the prophylactic Efficacy of a Single Immunization of Ad26.RSV.preF Against Respiratory Syncytial Virus Infection in a Virus Challenge Model in Healthy 18 to 50 Year-Old Adults

INTERVENTION: Product Name: Ad26.RSV.preF Product Code: JNJ‐64400141‐AAA Pharmaceutical Form: Solution for injection INN or Proposed INN: Ad26.RSV.preF Other descriptive name: JNJ‐64400141‐AAA Concentration unit: U/ml unit(s)/millilitre Concentration type: equal Concentration number: 2x10e11‐ Pharmaceutical form of the placebo: Solution for injection Route of administration of the placebo: Intramuscular use CONDITION: Prophylactic respiratory syncytial virus (RSV) vaccine. Therapeutic area: Diseases [C] ‐ Virus Diseases [C02] PRIMARY OUTCOME: ; Secondary Objective: ‐To assess a trend for prophylactic efficacy of a single dose of Ad26.RSV.preF in the RSV challenge model in terms of reduction of nasal wash viral load as measured by the peak viral load of the RT‐PCR compared to placebo.; ‐ To assess the effect of a single dose of 1x10e11 vp of Ad26.RSV.preF on viral load, as measured by RT‐PCR and quantitative culture of RSV, and clinical symptoms on Day 6 and Day 7 post‐challenge compared to placebo.; ‐To assess a trend for prophylactic efficacy of a single dose of 1x10e11 vp of Ad26.RSV.preF in the RSV challenge model in terms of prevention of symptomatic RSV infection defined as two quantifiable RT‐PCR measurements and one or more positive clinical symptoms of any grade from two different categories in the symptom scoring system (Upper Respiratory, Lower Respiratory, Systemic), or one Grade 2 symptom from any category compared to placebo.; ; Full list of secondary objectives is available in section 2 of the protocol.; ; Main Objective: To assess a trend for the prophylactic efficacy of a single dose of 1x10e11 vp of Ad26.RSV.preF administered intramuscularly to adults aged 18‐50 years in the RSV challenge model in terms of reduction of nasal wash viral load as measured by the area under the curve (AUC) over time by quantitative reverse transcriptase‐polymerase chain reaction (RT‐PCR) compared to placebo. Primary end point(s): The primary endpoint is the VL‐AUC (area under curve for viral load) of RSV‐A Memphis 37b as determined by quantitative RT‐PCR assay of nasal wash samples. Timepoint(s) of evaluation of this end point: Nasal wash samples are taken every 12 (±1) hours beginning two days after inoculation of the challenge virus until discharge from the challenge Unit. SECONDARY OUTCOME: ; Secondary end point(s): 1. Peak viral load of RSV‐A Memphis 37b, defined as the maximum viral load as determined by quantitative RT‐PCR assay of nasal wash samples, observed over the entire time period.; ; 2. Occurrence of symptomatic RSV infection defined as two quantifiable RT‐PCR measurements at different time points plus symptoms of any grade from two different categories from the subject symptom card (SSC) or two quantifiable RT‐PCR measurements plus any Grade 2 symptom from any category.; The three SSC categories are:; ‐ Upper Respiratory symptoms: runny nose, stuffy nose, sneezing, sore throat, earache; ‐ Lower Respiratory symptoms: cough, shortness of breath, chess tightness, wheeze; ‐ Systemic symptoms: malaise, headache, muscle and/or joint ache, chilliness/ feverishness; ; 3. Occurrence of RSV infection defined as two quantifiable RT‐PCR measurements plus any clinical symptom of any severity.; ; 4. Total weight of mucus produced and tissue count.; ; 5. Safety and tolerability; ‐ Unsolicited adverse events (AEs) from informed consent form (ICF) signature until 28 days after vaccination, and from the entry into the Unit until 28 days after challenge.; ‐ Safety data including, but not limited to, physical examinations, vital signs, 12‐lead electrocardiograms (ECGs) and clinical laboratory results (including biochemistry, hematology, and urinalysis).; ‐ Serious adverse events (SAEs) throughout the study (from signing the ICF to the end of the study, 6 months after vaccination).; ‐ Solicited local and systemic AEs for 7 days after vaccination.; ; Timepoint(s) of evaluation of this end point: 1. Nasal wash samples are taken every 12 (±1) hours beginning two days after inoculation of the challenge virus until discharge from the challenge Unit.; ; 2. 3 and 4 ‐samples collected at multiple timepoints until discharge from the challenge unit; ; 5. ‐ unsolicited AEs from ICF signature until 28 days after vaccination and from entry to the Unit (Day ‐2 or ‐1) until 28 days after challenge; ‐ safety data throughout the study; ‐ SAEs throughout the study; ‐ solicited local and systemic AEs for 7 days after vaccination; INCLUSION CRITERIA: 1.Subject is a man or woman, =18 to =50 years old on the day of ICF signature. 2. Subjects must be in good health, without significant medical illness, on the basis of a medical evaluation that reveals the absence of any clinically relevant abnormality and includes a physical examination, and the results of clinical laboratory tests performed within 56 days of vaccination. If there are abnormalities, the subject may be included only if the investigator judges the abnormalities or deviations from normal to be not clinically significant. This determination must be recorded in the subject’s source documents and initialed by the investigator. 3. Subjects must have a non‐clinically significant 12‐lead ECG within 56 days of vaccination including: a) normal sinus rhythm (heart rate between 50 and 100 beats per minute [bpm], extremes included) b) QT interval corrected for heart