Study of Remdesivir in Participants Below 18 Years Old With COVID-19

TEAEs were defined as any AEs with an onset date on or after the study drug start date and no later than 30 days after permanent discontinuation of study drug and/or any AEs leading to premature discontinuation of study drug.

Treatment-emergent graded laboratory abnormalities were defined as values that increase at least 1 toxicity grade from baseline at any time post baseline up to and including the date of last dose of study drug plus 30 days. The laboratory abnormalities were graded using division of allergy and infectious diseases (DAIDS) scale. DAIDS scale is used to grade the severity of adult and pediatric unwanted medical events. Grade 1: mild event, Grade 2: moderate event, Grade: serious event, Grade 4: potentially life-threatening event.

Cmax is defined as maximum plasma concentration of drug. Plasma concentrations were drawn as follows: (1) for Cohorts 1-4 and 8 on Day 2 and Day 3 with Day 5 as optional; (2) for Cohorts 5-7 on Day 2 or Day 3.

AUCtau is defined as area under the concentration versus time curve over the dosing interval. Plasma concentrations were drawn as follows: (1) for Cohorts 1-4 and 8 on Day 2 and Day 3 with Day 5 as optional; (2) for Cohorts 5-7 on Day 2 or Day 3.

Clinical improvement was defined as ≥ 1-point and ≥ 2-point improvement from Baseline clinical status or recovery or discharged alive on 7-point ordinal scale. Recovery was defined as an improvement from a Baseline score of 2 - 5 to a score of 6 or 7 or an improvement from a Baseline score of 6 to 7 on the ordinal scale. The ordinal scale was used for the assessment of the clinical status at a given day using a 7-point ordinal scale with an increasing score indicating improvement. Scale: 1=Death, 2=Hospitalized, on invasive mechanical ventilation or ECMO, 3=Hospitalized, on non-invasive ventilation or high flow oxygen devices, 4=Hospitalized, requiring low flow supplemental oxygen, 5=Hospitalized, not requiring supplemental oxygen-requiring ongoing medical care COVID-19 related or otherwise), 6=Hospitalized, not requiring supplemental oxygen-no longer required ongoing medical care (other than RDV administration), 7=Not hospitalized. The 95% CI was based on the Clopper-Pearson method.

Time to discharge was the duration from the first dose date to getting discharged from the hospital.

Oxygen support status was derived from the 7-point ordinal scale score, 1 = death; 2 = invasive mechanical ventilation; 3 = high flow oxygen; 4 = low flow oxygen; 5 or 6 = room air; 7 = discharge. Change from Baseline for participants with oxygenation use status as '3=High Flow Oxygen', '4=Low Flow Oxygen' and '5=Room Air' at Baseline.

Mechanical ventilation status was derived from the 7-point ordinal scale score, 1 = death; 2 = invasive mechanical ventilation; 3 = high flow oxygen; 4 = low flow oxygen; 5 or 6 = room air; 7 = discharge.

Confirmed negative PCR is defined by as 2 consecutive negative PCR results or negative result at the last available sample for participants who completed or discontinued from the study. The assessment were done for the samples: nasal/oropharyngeal (OP), nasopharyngeal (NP)/oropharyngeal (OP), endotracheal (ET) aspirates, and rectal/fecal swabs.

Change from baseline in SARS-CoV-2 viral load up to Day 10 or up to the first negative PCR result with confirmation (whichever comes first) were reported. The assessment were done for the samples: nasal/oropharyngeal (OP) samples, nasopharyngeal (NP)/OP samples, endotracheal (ET) aspirates, and rectal/fecal swabs.

The PEWS was measured by 3 components, where 1= behavior, 2= perfusion assessed by capillary refill and heart rate, and 3= respiratory status assessed by respiratory rate, effort, and oxygen requirement. The score ranged between 0 to 9 point, with higher score representing the highest severity level. A negative change from baseline value indicated an improvement. Data are reported for participants with a PEWS behavior score ≥ 2 at baseline, and a ≥ 2-point improvement (indicated by a decrease) in PEWS behavior score by Day 10, participants with a PEWS behavior score ≥ 1 at baseline, with ≥ 1-point improvement in PEWS behavior score by Day 10 and participants who recovered in PEWS behavior, defined as a Baseline score of 1 through 3 improved to a score of 0.

Plasma concentrations were drawn as follows: (1) for Cohorts 1-4 and 8 on Day 2 and Day 3, with Day 5 as optional; (2) for Cohorts 5-7 on Day 2 or Day 3.

Participants who received at least one concomitant non-study COVID-19 medication from the first day of RDV treatment through the 30-day Follow-up visit or early withdrawal are reported.