Inclusion criteria:
Each potential participant must satisfy all of the following criteria to be enrolled in the study:
1. Male or female.
2. 18 to 75 years of age, inclusive. Subjects =13 and <18 years of age may be enrolled in selected countries and study sites consistent with local regulations. Note: Adolescent participants will not be included in the study in Germany.
3. Received an autologous or allogeneic HSCT using any conditioning regimen.
4. ALC <1,000 cells/µL. The local assessment confirming ALC <1,000 cells/µL should be performed no more than 48 hours prior to randomization.
5. The participant has been diagnosed with RSV infection using a rapid PCR- or other molecular-based diagnostic assay performed on a bilateral mid-turbinate nasal swab sample as part of the study-specific screening assessment or on an upper respiratory tract sample as part of SOC testing.
6. New onset of at least 1 of the following respiratory symptoms within 4 days prior to the anticipated start of dosing (Day 1): nasal congestion, rhinorrhea, cough or pharyngitis (sore throat), and/or worsening of one of these chronic (associated with previously existing diagnosis, eg, chronic rhinorrhea, seasonal allergies, chronic lung disease) respiratory symptoms within 4 days prior to the anticipated start of dosing (Day 1).
7. No evidence of new abnormalities consistent with LRTI on a chest X-ray relative to the most recent chest X-ray, as determined by the local radiologist (preferentially) or the investigator. A chest X-ray should be performed no more than 48 hours prior to randomization. If a chest X-ray has not been obtained as part of SOC, it must be obtained during Screening.
Are the trial subjects under 18? no
Number of subjects for this age range:
F.1.2 Adults (18-64 years) yes
F.1.2.1 Number of subjects for this age range 200
F.1.3 Elderly (>=65 years) yes
F.1.3.1 Number of subjects for this age range 49
Exclusion criteria:
Any potential participant who meets any of the following criteria will be excluded from participating in the study:
1. Admitted to the hospital primarily for a lower respiratory tract disease of any cause as determined by the investigator.
2. Requires supplemental oxygen at Screening or any time between Screening and randomization.
3. Documented to be positive for other respiratory viruses (limited to influenza, parainfluenza, human rhinovirus, adenovirus, human metapneumovirus, or coronavirus) within 7 days prior to or at the Screening visit, if determined by local SOC testing (additional testing is not required).
4. Clinically significant bacteremia or fungemia within 7 days prior to or at Screening that has not been adequately treated, as determined by the investigator.
5. Known allergies, hypersensitivity, or intolerance to JNJ-53718678 or its excipients.
6. Bacterial, fungal, or viral pneumonia within 2 weeks prior to Screening that has not been adequately treated, as determined by the investigator.
7. Criterion modified per Amendment 2/DEU-1.
7.1 Criterion modified per Amendment 3.
7.2 Confirmed QTcF interval >450 milliseconds per the machine read parameter result at Screening. Presence of an abnormal QTcF interval should be confirmed by repeat ECG recording during Screening.
8. Criterion modified per Amendment 2/DEU-1.
8.1 Criterion modified per Amendment 5
8.2 Clinically significant abnormal ECG findings (other than QTcF interval >450 milliseconds, see exclusion criterion 7.2) not consistent with the underlying condition in the study population, as judged by the investigator based on the machine read ECG results at Screening.
9. Has evidence of one of the following ECG abnormalities per the machine read ECG results at Screening confirmed by repeat ECG recording:
- Repetitive premature ventricular contractions (>10/min)
- Second- or third-degree heart block
- Complete or incomplete left bundle branch block or complete right bundle branch block
