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Exploratory Study to Estimate the Prophylactic Efficacy of Palivizumab in Healthy Adult Participants Inoculated With RSV

A Double-Blind, Randomised, Placebo-Controlled Exploratory Study to Estimate the Prophylactic Efficacy of Palivizumab in Healthy Adult Participants Inoculated With Respiratory Syncytial Virus (RSV)

Status
Completed
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT04540627
Enrollment
56
Registered
2020-09-07
Start date
2020-07-06
Completion date
2020-10-23
Last updated
2021-10-04

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Healthy Adult Participants

Brief summary

Double-Blind, Randomised, Placebo-Controlled Exploratory Study to Estimate the Prophylactic Efficacy of Palivizumab in Healthy Adult Participants Inoculated with Respiratory Syncytial Virus (RSV).

Detailed description

As no data exists for Palivizumab in the RSV human challenge model, this exploratory study is therefore planned to establish the margins of effect and variance of prophylactically administered Palivizumab within the RSV-A Memphis 37b challenge model in healthy adult volunteers. The study will be performed in adults aged 18-55 years, in two parts. • Part 1: All participants will be administered Palivizumab (8mg/Kg, intravenously). Pharmacokinetic (PK), safety will be measured. If there are no safety concerns in Part 1, and PK analysis of Palivizumab treated participants confirm the modelling of 8mg/Kg to be appropriate, Part 2 will commence with the planned 8mg/Kg treatment dose. However, if PK analysis of Part 1 suggests that 8mg/kg may be insufficient dose to provide suitable efficacious coverage in Part 2, then Part 2 will proceed with a dose of 15mg/Kg. • Part 2: Participants will be either administered Palivizumab (8mg/Kg or 15mg/Kg, as determined in Part ) or a placebo and they will subsequently be challenged with an RSV-A strain (Memphis 37b). The margin of effect and variance between groups will be measured, as well as safety and reactogenicity.

Interventions

Liquid solution in sterile water for injection (final concentration of 20mg/mL), intravenous infusion, single dose of 8mg/kg or 15mg/kg, administered at a rate of 1mL/min

DRUGPlacebo

Sodium Chloride 0.9% Solution (Normal Saline), intravenous infusion, single dose of 0mg/Kg, administered at a rate of 1mL/min

OTHERRSV-A Memphis 37b virus

Single Intranasal Virus Dose (challenge dose is approximately 4.5log10 PFU)

Sponsors

mAbxience Research S.L.
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
TRIPLE (Subject, Caregiver, Investigator)

Eligibility

Sex/Gender
ALL
Age
18 Years to 55 Years
Healthy volunteers
Yes

Inclusion criteria

1. An informed consent document signed and dated by the participant and the Investigator. 2. Aged between 18 and 55 years old on the day of signing the consent form. 3. In good health with no history, or current evidence, of clinically significant medical conditions, and no clinically significant test abnormalities that will interfere with participant safety, as defined by medical history, physical examination, (including vital signs), Electrocardiogram (ECG), and routine laboratory tests as determined by the Investigator. 4. A documented medical history prior to enrolment. 5. The following criteria are applicable to female participants participating in the study. 1. Females of childbearing potential must have a negative pregnancy test prior to enrolment. 2. Females of non-childbearing potential: <!-- --> 1. Post- menopausal females; defined as having a history of amenorrhea for \>12 months with no alternative medical cause, and /or by Follicle stimulating hormone (FSH) level \>40mIU/mL, confirmed by laboratory 2. Documented status as being surgically sterile (e.g. tubal ligation, hysterectomy, bilateral salpingectomy and bilateral oophorectomy). 6. The following criteria apply to female and male participants: 1. Female participants of childbearing potential must use one form of highly effective contraception. Hormonal methods must be in place from at least 2 weeks prior to the first study visit. The contraception use must continue until 30 days after the date of viral challenge/last dosing with IMP (whichever occurs last). Highly effective contraception is as described below: <!-- --> 1. Established use of hormonal methods of contraception described below (for a minimum of 2 weeks prior to the first study visit). When hormonal methods of contraception are used, male partners are required to use a condom with a spermicide: 1\. Oral 2. Intravaginal 3. Transdermal b. Intrauterine device (IUD) c. Intrauterine hormone-releasing system (IUS) d. Bilateral tubal ligation e. Male sterilisation (with the appropriate post vasectomy documentation of the absence of sperm in the ejaculate) where the vasectomised male is the sole partner for that woman. f. True abstinence - sexual abstinence is considered a highly effective method only if defined as refraining from heterosexual intercourse during the entire period of risk associated with the study treatments. The reliability of sexual abstinence needs to be evaluated in relation to the duration of the clinical trial and the preferred and usual lifestyle of the participant. b) Male participants must agree to the contraceptive requirements below at entry to quarantine and continuing until 90 days after the date of Viral challenge / last dosing with the investigational medicinal product (IMP) (whichever occurs last): 1. Use a condom with a spermicide to prevent pregnancy in a female partner or to prevent exposure of any partner (male and female) to the IMP. 2. Male sterilisation with the appropriate post vasectomy documentation of the absence of sperm in the ejaculate (please note that the use of condom with spermicide will still be required to prevent partner exposure). This applies only to males participating in the study 3. In addition, for female partners of childbearing potential, that partner must use another form of contraception such as one of the highly effective methods mentioned above for female participants. 4. True abstinence - sexual abstinence is considered a highly effective method only if defined as refraining from heterosexual intercourse during the entire period of risk associated with the study treatments. The reliability of sexual abstinence needs to be evaluated in relation to the duration of the clinical trial and the preferred and usual lifestyle of the participant. c) In addition to the contraceptive requirements above, male participants must agree not to donate sperm following discharge from quarantine until 90 days after the date of Viral Challenge/last dosing with IMP (whichever occurs last). 7\. For Part 2 of the study: Sero-suitable to the challenge virus, as defined in the study Analytical Plan.

Exclusion criteria

Medical History 1. History of, or currently active, symptoms or signs suggestive of upper or lower respiratory tract infection within 4 weeks prior to the first study visit. 2. a) Any history or evidence of any other clinically significant or currently active systemic comorbidities including psychiatric disorders (includes participants with a history of depression and/or anxiety). b) And/or other major disease that, in the opinion of the Investigator, may put the participant at undue risk, or interfere with a participant completing the study and necessary investigations. The following conditions apply: • Participants with clinically mild atopic eczema/atopic dermatitis and clinically mild psoriasis may be included at the Investigator's discretion (e.g., if small amounts of regular topical steroids are used, no eczema in cubital fossa; moderate to large amounts of daily dermal corticosteroids is an exclusion). * Rhinitis (including hay fever) which is clinically active or history of moderate to severe rhinitis, or history of seasonal allergic rhinitis likely to be active at the time of inclusion into the study and/or requiring regular nasal corticosteroids on an at least weekly basis, within 30 days of admission to quarantine will be excluded. Participants with a history of currently inactive rhinitis (within the last 30 days) or mild rhinitis may be included at the PI's discretion. * Participants with a physician diagnosed underactive thyroid who have been controlled on treatment for at least 6 months with evidence of a normal thyroid function test (TFT) can be included at the discretion of the PI. * Any concurrent serious illness including history of malignancy that may interfere with the aims of the study or a participant completing the study. Basal cell carcinoma within 5 years of initial diagnosis or with evidence of recurrence is also an exclusion. o Participants with a history of psychiatric illness including depression and/or anxiety of any severity within the last 2 years can be included if the Patient Health Questionnaire (PHQ-9) and / or the Generalised Anxiety Disorder Questionnaire (GAD-7) is less than or equal to 4. Participants with a PHQ-9 or GAD-7 score of between 5 and 9 may be included following consultation with a Senior Physician (Clinical Lead for Screening) who may advise further consultation with the PI. o Participants reporting physician diagnosed migraine can be included provided there are no associated neurological symptoms such as hemiplegia or visual loss. Cluster headache/migraine or prophylactic treatment for migraine is an exclusion. * Participants with physician diagnosed mild Irritable Bowel Syndrome (IBS) not requiring regular treatment can be included at the discretion of the PI. 3. Participants who have smoked ≥ 10 pack years at any time \[10 pack years is equivalent to one pack of 20 cigarettes a day for 10 years\]). 4. A total body weight ≤ 50 kg and Body Mass Index (BMI) ≤18 kg/m2 and ≥30kg/m2 5. Females who: 1. Are breastfeeding, or 2. Have been pregnant within 6 months prior to the study. 6. History of anaphylaxis-and/or a history of severe allergic reaction or significant intolerance to any food or drug, as assessed by the PI. 7. Venous access deemed inadequate for the phlebotomy and cannulation demands of the study. 8. a) For Part 2 of the study: Any significant abnormality altering the anatomy of the nose in a substantial way or nasopharynx that may interfere with the aims of the study and in particular any of the nasal assessments or viral challenge, (historical nasal polyps can be included, but large nasal polyps causing current and significant symptoms and/or requiring regular treatments in the last month will be excluded). b) Any clinically significant history of epistaxis (large nosebleeds) within the last 3 months of the first study visit and/or history of being hospitalized due to epistaxis on any previous occasion. c) Any nasal or sinus surgery within 3 months of the first study visit. Prior or Concomitant Medications and Assessments 9. For Part 2 of the study: 1. Evidence of vaccinations within the 4 weeks prior to the planned date of viral challenge/first dosing with IMP (whichever occurs first). 2. Intention to receive any vaccination(s) before the last day of Follow-up. (NB. No travel restrictions will apply after the Day 28 (±3 days) Follow-up Visit). 10. Receipt of blood or blood products, or loss (including blood donations) of 470 mL or more of blood during the 3 months prior to the planned date of viral challenge/first dosing with IMP (whichever occurs first) or planned during the 3 months after the final visit. 11. a) Receipt of any investigational drug within 3 months prior to the planned date of viral challenge/first dosing with IMP (whichever occurs first). b) Receipt of three or more investigational drugs within the previous 12 months prior to the planned date of viral challenge/first dosing with IMP (whichever occurs first). For Part 2 of the study: c) Prior inoculation with a virus from the same virus-family as the challenge virus. d) Prior participation in another human viral challenge study with a respiratory virus in the preceding 3 months, taken from the date of viral challenge in the previous study to the date of expected viral challenge in this study 12. a) Confirmed positive test for drugs of abuse on first study visit. One repeat test allowed at PI discretion. b) History or presence of alcohol addiction, or excessive use of alcohol (weekly intake in excess of 28 units alcohol; 1 unit being a half glass of beer, a small glass of wine or a measure of spirits), or excessive consumption of xanthine containing substances (e.g. daily intake in excess of 5 cups of caffeinated drinks e.g. coffee, tea, cola). 13. For Part 2 of the study: A forced expiratory volume in 1 second (FEV1) \< 80%. 14. Positive human immunodeficiency virus (HIV), active hepatitis A (HAV), B (HBV), or C (HCV) test. Other 15. Those employed or immediate relatives of those employed at hVIVO or the Sponsor. 16. Any other finding that, in the opinion of the Investigator, deems the participant unsuitable for the study.

Design outcomes

Primary

MeasureTime frameDescription
Mean Serum Concentrations (Cmax) for Open-label Palivizumab (Part 1) on Day 12.In Part 1: before the start of infusion; at end of infusion,15 minutes and 0.5, 1, 4, 8, and 12 hours after infusion; and at 1, 2, 3, 7, and 12 days after infusion.The PK assessment up to and including Day 12 exposure was used as a decision information for the dose to be given to participants in Part 2. Pharmacokinetic exposure data from at least 5 out of 6 participants were required for dose decision making with a projected exposure of ≥40 μg/mL on Day 12 according to the protocol. This was achieved after administration of a single IV dose of Palivizumab at 8 mg/kg. Therefore, a dose of 8 mg/kg was chosen for Part 2.
Area Under the Viral Load-time Curve (VL-AUC) as Determined by Polymerase Chain Reaction (qRT-PCR) on Nasal Samples, for Double-blind Palivizumab or Placebo (Part 2).From two days post viral challenge (Day 2) to the end of quarantine (Day 12) in Part 2 on nasal samples collected twice daily.RSV viral load of RSV-A Memphis 37b as determined by qRT-PCR on nasal samples collected twice daily: Assessment of the Area under the viral load-time curve (VL-AUC)
qRT-PCR Peak Viral Load for Double-blind Palivizumab or Placebo (Part 2).From two days post viral challenge (Day 2) to the end of quarantine (Day 12) in Part 2Peak viral load of RSV-A Memphis 37b as determined by qRT-PCR on nasal samples collected twice daily.

Secondary

MeasureTime frameDescription
Number of Participants With Laboratory-confirmed Infection of RSV-A Memphis 37b in Nasal Samples (Variant 1) for Double-blind Palivizumab or Placebo (Part 2).From Day 2 to Day 12 in Part 2Percentage of Participants Infected Post-viral Challenge (Infectivity Status and Rate): occurrence of at least 2 positive quantifiable qRT-PCR measurements in nasal samples. Laboratory-confirmed infection (variant 1): At least 2 positive quantifiable detections by viral load qRT-PCR assay specific for the challenge virus, reported within 4 consecutive scheduled assessments and from 2 independent samples from Day 2 until discharge and/or 1 positive detection by viral load qRT-PCR assay, specific for the challenge virus, in which an aliquot of the same sample has also tested positive in a viral culture assay appropriate for detecting the challenge virus from Day 2 until discharge.
Number of Participants With Laboratory-confirmed Infection of RSV-A Memphis 37b in Nasal Samples (Variant 2), for Double-blind Palivizumab or Placebo (Part 2).From Day 2 to Day 12 in Part 2Percentage of Participants Infected Post-viral Challenge (Infectivity Status and Rate): Occurrence of at least 2 positive detectable qRT-PCR measurements in nasal samples. Laboratory-confirmed infection (variant 2): At least 2 positive detectable assessments by viral load qRT-PCR assay specific for the challenge virus, reported within 4 consecutive scheduled assessments and from 2 independent samples from Day 2 until discharge and/or 1 positive detection by viral load qRT-PCR assay, specific for the challenge virus, in which an aliquot of the same sample has also tested positive in a viral culture assay appropriate for detecting the challenge virus from Day 2 until discharge.
Viral Shedding of RSV-A Memphis 37b in Nasal Samples in Terms of Duration, for Double-blind Palivizumab or Placebo (Part 2).From Day 2 to Day 12 in Part 2Estimation of the duration of viral shedding by the number of days with quantifiable qRT-PCR measurements in nasal samples starting 2 days post viral challenge (Day 2) up to the end of quarantine.
Viral Shedding of RSV-A Memphis 37b in Nasal Samples in Terms of Time to Peak Viral Load, for Double-blind Palivizumab or Placebo (Part 2).From Day 2 to Day 12 in Part 2Estimation of the duration of viral shedding by the time to peak viral load of RSV by quantifiable qRT-PCR.
Viral Shedding of RSV-A Memphis 37b in Nasal Samples in Terms of Peak Viral Load, for Double-blind Palivizumab or Placebo (Part 2).From Day 2 to Day 12 in Part 2Peak viral load of RSV-A Memphis 37b as defined by the maximum viral load determined by quantifiable qRT PCR measurements in nasal samples starting 2 days post viral challenge (Day 2) up to the end of quarantine.
Total Symptom Score (TSS)-Time Curve (AUC) Collected Daily in the Participant Symptom Diary CardFrom two days post viral challenge (Day 2) to the end of quarantine (Day 12) in Part 2 on nasal samples collected twice daily.Mean TSS values (collected daily in the symptom diary card) over time. Symptoms were collected using the hVIVO (services provider) symptom diary card. Several symptoms (such as runny nose, sore throat, earache, etc) in the 13-item questionnaire were graded on a scale of 0-3 (grade 0: No symptoms; grade 1: just noticeable; grade 2: clearly bothersome from time to time but does not interfere with me doing my normal daily activities; grade 3: Quite bothersome most or all of the time, and it stops me participating in activities). Shortness of breath and wheeze have an additional grade 4: Symptoms at rest. The total symptom score (TSS) was determined as the sum of the symptom scores ranging from 0.0 (min) to 41(max) \[or a maximum of 41x11.33=464.67 depending on what the reviewer is asking\] using a 13-items self-reported diary card. 11.33 is the number of days symptom diary cards were included (Day +1 morning dairy card to Day 12 morning diary card). Higher scores mean worse outcome.
Peak Symptom ScoresFrom Day 2 to Day 12 in Part 2Peak symptom scores for symptoms collected daily in the participant symptom diary card. Symptoms (such as runny nose, sore throat, earache, etc) were collected using the 13-item hVIVO symptom questionnaire and were graded on a scale of 0-3 (grade 0: No symptoms; grade 1: just noticeable; grade 2: clearly bothersome from time to time but does not interfere with me doing my normal daily activities; grade 3: Quite bothersome most or all of the time, and it stops me participating in activities). Shortness of breath and wheeze have an additional grade 4: Symptoms at rest. The total symptom score (TSS) was determined as the sum of the symptom scores ranging from 0.0 (min) to 41(max) \[or a maximum of 41x11.33=464.67 depending on what the reviewer is asking\] using a 13-items self-reported diary card. 11.33 is the number of days symptom diary cards were included (Day +1 morning dairy card to Day 12 morning diary card). Higher scores mean worse outcome.
Total Weight of Nasal Discharge ProducedFrom Day 1 to Day 12 in Part 2Nasal Discharge Collection from Paper Tissues by means of the total weight of nasal discharge produced.
CmaxBefore the start of infusion; at end of infusion, 15 minutes and 0.5, 1, 4, 8, and 12 hours after infusion; and at 1, 2, 3, 7 and 12 days after infusion (Part 1) or at 1, 2, 3, 7, 13, 21, and 29 days after infusion (Part 2)Evaluation of Palivizumab PK levels throughout the study, by means of Cmax after intravenous administration of Palivizumab.
Number of Participants With Laboratory-confirmed Virus-like Illness (Variant 1) Using Viral Shedding Variant 1, for Double-blind Palivizumab or Placebo (Part 2).From Day 2 to Day 12 in Part 2Illness Post-viral challenge measured by means of the proportion of participants with any symptom ≥grade 1 for the evaluable population.
The Occurrence of Laboratory-confirmed Virus-like Illness (Variant 1) Using Viral Shedding Variant 2, for Double-blind Palivizumab or Placebo (Part 2).From Day 2 to Day 12 in Part 2Illness Post-viral challenge measured by means of the proportion of participants with any symptom ≥grade 1 for the evaluable population.
The Occurrence of Laboratory-confirmed Virus-like Illness (Variant 2) Using Viral Shedding Variant 1, for Double-blind Palivizumab or Placebo (Part 2).From Day 2 to Day 12 in Part 2Illness Post-viral challenge measured by means of the proportion of participants with any symptom ≥grade 1 for the evaluable population.
The Occurrence of Laboratory-confirmed Virus-like Illness (Variant 2) Using Viral Shedding Variant 2, for Double-blind Palivizumab or Placebo (Part 2).From Day 2 to Day 12 in Part 2Illness Post-viral challenge measured by means of the proportion of participants with any symptom ≥grade 1 for the evaluable population.
TmaxBefore the start of infusion; at end of infusion, 15 minutes and 0.5, 1, 4, 8, and 12 hours after infusion; and at 1, 2, 3, 7, and 12 days after infusion (Part 1) or at 1, 2, 3, 7, 13, 21, and 29 days after infusion (Part 2)Palivizumab PK levels throughout the study, by means of Tmax after intravenous administration of Palivizumab.
Safety Adults: Number of Participants With Adverse Events (AEs)From Day 1 to Day 18 in Part 1 and from Day 1 to Day 28 in Part 2Incidence of AEs, treatment-emergent AEs (TEAEs), serious AEs (SAEs) and; drug-related or challenge-virus related TEAEs and SAEs
Immunogenicity: Number of Participants Positive for Anti-palivizumab Antibody (ADA)Part 2: prior to infusion with Palivizumab and 7, 13, and 29 days post Palivizumab infusion.Determination of the incidence of anti-palivizumab ADA (number and percent of participants tested positive for anti-palivizumab ADA). ADA positive participant: baseline negative and any sample after treatment positive, or baseline positive and titre increased 4- to 9-fold after treatment) before the dose of palivizumab and at scheduled post-dose assessments.
Total Number of Tissues Used by ParticipantsFrom Day 1 to Day 12 in Part 2Nasal Discharge Collection from Paper Tissues by means of the total number of tissues used.
Area Under the Viral Load-time Curve (VL-AUC) as Determined by Cell Culture on Nasal Samples, for Double-blind Palivizumab (Part 2).From two days post viral challenge (Day 2) to the end of quarantine (Day 12) in Part 2 on nasal samples collected twice daily.RSV Viral Load of RSV-A Memphis 37b as Determined by Cell Culture on Nasal Samples collected twice daily: Area under the viral load-time curve (VL-AUC) of RSV-A Memphis 37b
Cell Culture Peak Viral Load for Double-blind Palivizumab or Placebo (Part 2).From Day 2 to Day 12 in Part 2Peak Viral Load of RSV-A Memphis 37b as Determined by Cell Culture on Nasal Sample

Countries

United Kingdom

Participant flow

Pre-assignment details

The study was conducted in 2 parts: Part 1 (PK sentinel part) and Part 2 (viral challenge part). Part 1: Open-label. This part of the study was used to determine the dose of Palivizumab IV for Part 2 (8 or 15 mg/kg). Part 2: Double-blind, randomized, and placebo-controlled. Participants received a single IV dose of either Palivizumab (8 mg/kg, as finally determined in Part 1) or a placebo and were subsequently challenged with an RSV-A strain.

Participants by arm

ArmCount
Open-label Palivizumab (Part 1)
Sterile vial 50mg/0.5mL Palivizumab: Liquid solution in sterile water for injection (final concentration of 20mg/mL), intravenous infusion, single dose of 8mg/kg, administered at a rate of 1mL/min
6
Double-blind Placebo (Part 2)
Sodium Chloride 0.9% Solution (Normal Saline) Placebo: Sodium Chloride 0.9% Solution (Normal Saline), intravenous infusion, single dose of 0mg/Kg, administered at a rate of 1mL/min RSV-A Memphis 37b virus: Single Intranasal Virus Dose (challenge dose is approximately 4.5log10 PFU)
25
Double-blind Palivizumab (Synagis™) (Part 2)
Sterile vial 50mg/0.5mL Palivizumab: Liquid solution in sterile water for injection (final concentration of 20mg/mL), intravenous infusion, single dose of 8mg/kg, administered at a rate of 1mL/min RSV-A Memphis 37b virus: Single Intranasal Virus Dose (challenge dose is approximately 4.5log10 PFU)
25
Total56

Baseline characteristics

CharacteristicDouble-blind Placebo (Part 2)Double-blind Palivizumab (Synagis™) (Part 2)TotalOpen-label Palivizumab (Part 1)
Age, Continuous28.16 years
STANDARD_DEVIATION 6.3
26.76 years
STANDARD_DEVIATION 5.83
26.86 years
STANDARD_DEVIATION 4.9
25.67 years
STANDARD_DEVIATION 2.58
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants1 Participants1 Participants0 Participants
Race (NIH/OMB)
Asian
0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
Black or African American
0 Participants2 Participants2 Participants0 Participants
Race (NIH/OMB)
More than one race
2 Participants2 Participants6 Participants2 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
White
23 Participants20 Participants47 Participants4 Participants
Sex: Female, Male
Female
12 Participants5 Participants19 Participants2 Participants
Sex: Female, Male
Male
13 Participants20 Participants37 Participants4 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
0 / 250 / 25
other
Total, other adverse events
12 / 2514 / 25
serious
Total, serious adverse events
0 / 251 / 25

Outcome results

Primary

Area Under the Viral Load-time Curve (VL-AUC) as Determined by Polymerase Chain Reaction (qRT-PCR) on Nasal Samples, for Double-blind Palivizumab or Placebo (Part 2).

RSV viral load of RSV-A Memphis 37b as determined by qRT-PCR on nasal samples collected twice daily: Assessment of the Area under the viral load-time curve (VL-AUC)

Time frame: From two days post viral challenge (Day 2) to the end of quarantine (Day 12) in Part 2 on nasal samples collected twice daily.

Population: The evaluable population includes 49 participants. All participants in this population received study intervention, were inoculated with challenge virus, and completed quarantine. One Palivizumab-treated participant was excluded from the evaluable population because the participant had not completed the quarantine period.

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)Area Under the Viral Load-time Curve (VL-AUC) as Determined by Polymerase Chain Reaction (qRT-PCR) on Nasal Samples, for Double-blind Palivizumab or Placebo (Part 2).11.68 Log10 copies*day/mLStandard Deviation 15.36
Double-blind Placebo (Part 2)Area Under the Viral Load-time Curve (VL-AUC) as Determined by Polymerase Chain Reaction (qRT-PCR) on Nasal Samples, for Double-blind Palivizumab or Placebo (Part 2).9.94 Log10 copies*day/mLStandard Deviation 12.38
p-value: 0.5802Wilcoxon (Mann-Whitney)
Primary

Mean Serum Concentrations (Cmax) for Open-label Palivizumab (Part 1) on Day 12.

The PK assessment up to and including Day 12 exposure was used as a decision information for the dose to be given to participants in Part 2. Pharmacokinetic exposure data from at least 5 out of 6 participants were required for dose decision making with a projected exposure of ≥40 μg/mL on Day 12 according to the protocol. This was achieved after administration of a single IV dose of Palivizumab at 8 mg/kg. Therefore, a dose of 8 mg/kg was chosen for Part 2.

Time frame: In Part 1: before the start of infusion; at end of infusion,15 minutes and 0.5, 1, 4, 8, and 12 hours after infusion; and at 1, 2, 3, 7, and 12 days after infusion.

Population: All participants treated had at least 1 post-dose PK result; therefore, all participants were included in the PK analysis population. One participant had an interrupted IV infusion of Palivizumab but received the complete dose of 8 mg/kg.

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)Mean Serum Concentrations (Cmax) for Open-label Palivizumab (Part 1) on Day 12.71.2 μg/mLStandard Deviation 6.11
Primary

qRT-PCR Peak Viral Load for Double-blind Palivizumab or Placebo (Part 2).

Peak viral load of RSV-A Memphis 37b as determined by qRT-PCR on nasal samples collected twice daily.

Time frame: From two days post viral challenge (Day 2) to the end of quarantine (Day 12) in Part 2

Population: The evaluable population includes 49 participants. All participants in this population received study intervention, were inoculated with challenge virus, and completed quarantine. One Palivizumab-treated participant was excluded from the evaluable population because the participant had not completed the quarantine period.

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)qRT-PCR Peak Viral Load for Double-blind Palivizumab or Placebo (Part 2).3.66 Log10 copies/mLStandard Deviation 2.42
Double-blind Placebo (Part 2)qRT-PCR Peak Viral Load for Double-blind Palivizumab or Placebo (Part 2).3.11 Log10 copies/mLStandard Deviation 2.65
p-value: 0.4868Wilcoxon (Mann-Whitney)
Secondary

Area Under the Viral Load-time Curve (VL-AUC) as Determined by Cell Culture on Nasal Samples, for Double-blind Palivizumab (Part 2).

RSV Viral Load of RSV-A Memphis 37b as Determined by Cell Culture on Nasal Samples collected twice daily: Area under the viral load-time curve (VL-AUC) of RSV-A Memphis 37b

Time frame: From two days post viral challenge (Day 2) to the end of quarantine (Day 12) in Part 2 on nasal samples collected twice daily.

Population: Evaluable population

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)Area Under the Viral Load-time Curve (VL-AUC) as Determined by Cell Culture on Nasal Samples, for Double-blind Palivizumab (Part 2).2.05 Log10 PFU*day/mLStandard Deviation 5.29
Double-blind Placebo (Part 2)Area Under the Viral Load-time Curve (VL-AUC) as Determined by Cell Culture on Nasal Samples, for Double-blind Palivizumab (Part 2).1.64 Log10 PFU*day/mLStandard Deviation 3.43
p-value: 0.2681Wilcoxon (Mann-Whitney)
Secondary

Cell Culture Peak Viral Load for Double-blind Palivizumab or Placebo (Part 2).

Peak Viral Load of RSV-A Memphis 37b as Determined by Cell Culture on Nasal Sample

Time frame: From Day 2 to Day 12 in Part 2

Population: Evaluable population

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)Cell Culture Peak Viral Load for Double-blind Palivizumab or Placebo (Part 2).0.60 Log10 PFU/mLStandard Deviation 1.47
Double-blind Placebo (Part 2)Cell Culture Peak Viral Load for Double-blind Palivizumab or Placebo (Part 2).0.88 Log10 PFU/mLStandard Deviation 1.41
p-value: 0.2431Wilcoxon (Mann-Whitney)
Secondary

Cmax

Evaluation of Palivizumab PK levels throughout the study, by means of Cmax after intravenous administration of Palivizumab.

Time frame: Before the start of infusion; at end of infusion, 15 minutes and 0.5, 1, 4, 8, and 12 hours after infusion; and at 1, 2, 3, 7 and 12 days after infusion (Part 1) or at 1, 2, 3, 7, 13, 21, and 29 days after infusion (Part 2)

Population: All participants treated had at least 1 post-dose PK result; therefore, all participants were included in the PK analysis population. One participant had an interrupted IV infusion of Palivizumab but received the complete dose of 8 mg/kg.

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)Cmax262 μg/mLStandard Deviation 35.6
Double-blind Palivizumab (Synagis™) (Part 2)Cmax283 μg/mLStandard Deviation 46.5
Secondary

Immunogenicity: Number of Participants Positive for Anti-palivizumab Antibody (ADA)

Determination of the incidence of anti-palivizumab ADA (number and percent of participants tested positive for anti-palivizumab ADA). ADA positive participant: baseline negative and any sample after treatment positive, or baseline positive and titre increased 4- to 9-fold after treatment) before the dose of palivizumab and at scheduled post-dose assessments.

Time frame: Part 2: prior to infusion with Palivizumab and 7, 13, and 29 days post Palivizumab infusion.

Population: Safety analysis population: All participants randomly assigned to study intervention and who took a dose of study intervention, regardless of whether they received the challenge virus or not.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Open-label Palivizumab (Part 1)Immunogenicity: Number of Participants Positive for Anti-palivizumab Antibody (ADA)0 Participants
Secondary

Number of Participants With Laboratory-confirmed Infection of RSV-A Memphis 37b in Nasal Samples (Variant 1) for Double-blind Palivizumab or Placebo (Part 2).

Percentage of Participants Infected Post-viral Challenge (Infectivity Status and Rate): occurrence of at least 2 positive quantifiable qRT-PCR measurements in nasal samples. Laboratory-confirmed infection (variant 1): At least 2 positive quantifiable detections by viral load qRT-PCR assay specific for the challenge virus, reported within 4 consecutive scheduled assessments and from 2 independent samples from Day 2 until discharge and/or 1 positive detection by viral load qRT-PCR assay, specific for the challenge virus, in which an aliquot of the same sample has also tested positive in a viral culture assay appropriate for detecting the challenge virus from Day 2 until discharge.

Time frame: From Day 2 to Day 12 in Part 2

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Open-label Palivizumab (Part 1)Number of Participants With Laboratory-confirmed Infection of RSV-A Memphis 37b in Nasal Samples (Variant 1) for Double-blind Palivizumab or Placebo (Part 2).13 Participants
Double-blind Placebo (Part 2)Number of Participants With Laboratory-confirmed Infection of RSV-A Memphis 37b in Nasal Samples (Variant 1) for Double-blind Palivizumab or Placebo (Part 2).12 Participants
Secondary

Number of Participants With Laboratory-confirmed Infection of RSV-A Memphis 37b in Nasal Samples (Variant 2), for Double-blind Palivizumab or Placebo (Part 2).

Percentage of Participants Infected Post-viral Challenge (Infectivity Status and Rate): Occurrence of at least 2 positive detectable qRT-PCR measurements in nasal samples. Laboratory-confirmed infection (variant 2): At least 2 positive detectable assessments by viral load qRT-PCR assay specific for the challenge virus, reported within 4 consecutive scheduled assessments and from 2 independent samples from Day 2 until discharge and/or 1 positive detection by viral load qRT-PCR assay, specific for the challenge virus, in which an aliquot of the same sample has also tested positive in a viral culture assay appropriate for detecting the challenge virus from Day 2 until discharge.

Time frame: From Day 2 to Day 12 in Part 2

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Open-label Palivizumab (Part 1)Number of Participants With Laboratory-confirmed Infection of RSV-A Memphis 37b in Nasal Samples (Variant 2), for Double-blind Palivizumab or Placebo (Part 2).15 Participants
Double-blind Placebo (Part 2)Number of Participants With Laboratory-confirmed Infection of RSV-A Memphis 37b in Nasal Samples (Variant 2), for Double-blind Palivizumab or Placebo (Part 2).15 Participants
Secondary

Number of Participants With Laboratory-confirmed Virus-like Illness (Variant 1) Using Viral Shedding Variant 1, for Double-blind Palivizumab or Placebo (Part 2).

Illness Post-viral challenge measured by means of the proportion of participants with any symptom ≥grade 1 for the evaluable population.

Time frame: From Day 2 to Day 12 in Part 2

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Open-label Palivizumab (Part 1)Number of Participants With Laboratory-confirmed Virus-like Illness (Variant 1) Using Viral Shedding Variant 1, for Double-blind Palivizumab or Placebo (Part 2).11 Participants
Double-blind Placebo (Part 2)Number of Participants With Laboratory-confirmed Virus-like Illness (Variant 1) Using Viral Shedding Variant 1, for Double-blind Palivizumab or Placebo (Part 2).5 Participants
Secondary

Peak Symptom Scores

Peak symptom scores for symptoms collected daily in the participant symptom diary card. Symptoms (such as runny nose, sore throat, earache, etc) were collected using the 13-item hVIVO symptom questionnaire and were graded on a scale of 0-3 (grade 0: No symptoms; grade 1: just noticeable; grade 2: clearly bothersome from time to time but does not interfere with me doing my normal daily activities; grade 3: Quite bothersome most or all of the time, and it stops me participating in activities). Shortness of breath and wheeze have an additional grade 4: Symptoms at rest. The total symptom score (TSS) was determined as the sum of the symptom scores ranging from 0.0 (min) to 41(max) \[or a maximum of 41x11.33=464.67 depending on what the reviewer is asking\] using a 13-items self-reported diary card. 11.33 is the number of days symptom diary cards were included (Day +1 morning dairy card to Day 12 morning diary card). Higher scores mean worse outcome.

Time frame: From Day 2 to Day 12 in Part 2

Population: Evaluable population

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)Peak Symptom Scores4.16 score on a scaleStandard Error 3.45
Double-blind Placebo (Part 2)Peak Symptom Scores2.54 score on a scaleStandard Error 3.32
p-value: 0.0403Wilcoxon (Mann-Whitney)
Secondary

Safety Adults: Number of Participants With Adverse Events (AEs)

Incidence of AEs, treatment-emergent AEs (TEAEs), serious AEs (SAEs) and; drug-related or challenge-virus related TEAEs and SAEs

Time frame: From Day 1 to Day 18 in Part 1 and from Day 1 to Day 28 in Part 2

Population: Safety analysis population: All participants randomly assigned to study intervention and who took a dose of study intervention, regardless of whether they received the challenge virus or not.

ArmMeasureGroupValue (NUMBER)
Open-label Palivizumab (Part 1)Safety Adults: Number of Participants With Adverse Events (AEs)Any SAE related to the study treatment0 participants
Open-label Palivizumab (Part 1)Safety Adults: Number of Participants With Adverse Events (AEs)Any TEAE related to the challenge virus0 participants
Open-label Palivizumab (Part 1)Safety Adults: Number of Participants With Adverse Events (AEs)Any TEAE0 participants
Open-label Palivizumab (Part 1)Safety Adults: Number of Participants With Adverse Events (AEs)Any SAE leading to study discontinuation0 participants
Open-label Palivizumab (Part 1)Safety Adults: Number of Participants With Adverse Events (AEs)Any SAE0 participants
Open-label Palivizumab (Part 1)Safety Adults: Number of Participants With Adverse Events (AEs)Any AE0 participants
Open-label Palivizumab (Part 1)Safety Adults: Number of Participants With Adverse Events (AEs)Any SAE related to the challenge virus0 participants
Open-label Palivizumab (Part 1)Safety Adults: Number of Participants With Adverse Events (AEs)Any TEAE related to the study drug0 participants
Open-label Palivizumab (Part 1)Safety Adults: Number of Participants With Adverse Events (AEs)Any death0 participants
Double-blind Placebo (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any SAE related to the study treatment0 participants
Double-blind Placebo (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any AE12 participants
Double-blind Placebo (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any TEAE12 participants
Double-blind Placebo (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any TEAE related to the study drug1 participants
Double-blind Placebo (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any TEAE related to the challenge virus5 participants
Double-blind Placebo (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any SAE0 participants
Double-blind Placebo (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any SAE leading to study discontinuation0 participants
Double-blind Placebo (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any SAE related to the challenge virus0 participants
Double-blind Placebo (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any death0 participants
Double-blind Palivizumab (Synagis™) (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any SAE leading to study discontinuation0 participants
Double-blind Palivizumab (Synagis™) (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any TEAE related to the study drug4 participants
Double-blind Palivizumab (Synagis™) (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any SAE related to the study treatment0 participants
Double-blind Palivizumab (Synagis™) (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any TEAE14 participants
Double-blind Palivizumab (Synagis™) (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any death0 participants
Double-blind Palivizumab (Synagis™) (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any SAE related to the challenge virus1 participants
Double-blind Palivizumab (Synagis™) (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any SAE1 participants
Double-blind Palivizumab (Synagis™) (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any TEAE related to the challenge virus8 participants
Double-blind Palivizumab (Synagis™) (Part 2)Safety Adults: Number of Participants With Adverse Events (AEs)Any AE14 participants
Secondary

The Occurrence of Laboratory-confirmed Virus-like Illness (Variant 1) Using Viral Shedding Variant 2, for Double-blind Palivizumab or Placebo (Part 2).

Illness Post-viral challenge measured by means of the proportion of participants with any symptom ≥grade 1 for the evaluable population.

Time frame: From Day 2 to Day 12 in Part 2

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Open-label Palivizumab (Part 1)The Occurrence of Laboratory-confirmed Virus-like Illness (Variant 1) Using Viral Shedding Variant 2, for Double-blind Palivizumab or Placebo (Part 2).11 Participants
Double-blind Placebo (Part 2)The Occurrence of Laboratory-confirmed Virus-like Illness (Variant 1) Using Viral Shedding Variant 2, for Double-blind Palivizumab or Placebo (Part 2).5 Participants
Secondary

The Occurrence of Laboratory-confirmed Virus-like Illness (Variant 2) Using Viral Shedding Variant 1, for Double-blind Palivizumab or Placebo (Part 2).

Illness Post-viral challenge measured by means of the proportion of participants with any symptom ≥grade 1 for the evaluable population.

Time frame: From Day 2 to Day 12 in Part 2

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Open-label Palivizumab (Part 1)The Occurrence of Laboratory-confirmed Virus-like Illness (Variant 2) Using Viral Shedding Variant 1, for Double-blind Palivizumab or Placebo (Part 2).13 Participants
Double-blind Placebo (Part 2)The Occurrence of Laboratory-confirmed Virus-like Illness (Variant 2) Using Viral Shedding Variant 1, for Double-blind Palivizumab or Placebo (Part 2).11 Participants
Secondary

The Occurrence of Laboratory-confirmed Virus-like Illness (Variant 2) Using Viral Shedding Variant 2, for Double-blind Palivizumab or Placebo (Part 2).

Illness Post-viral challenge measured by means of the proportion of participants with any symptom ≥grade 1 for the evaluable population.

Time frame: From Day 2 to Day 12 in Part 2

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Open-label Palivizumab (Part 1)The Occurrence of Laboratory-confirmed Virus-like Illness (Variant 2) Using Viral Shedding Variant 2, for Double-blind Palivizumab or Placebo (Part 2).15 Participants
Double-blind Placebo (Part 2)The Occurrence of Laboratory-confirmed Virus-like Illness (Variant 2) Using Viral Shedding Variant 2, for Double-blind Palivizumab or Placebo (Part 2).14 Participants
Secondary

Tmax

Palivizumab PK levels throughout the study, by means of Tmax after intravenous administration of Palivizumab.

Time frame: Before the start of infusion; at end of infusion, 15 minutes and 0.5, 1, 4, 8, and 12 hours after infusion; and at 1, 2, 3, 7, and 12 days after infusion (Part 1) or at 1, 2, 3, 7, 13, 21, and 29 days after infusion (Part 2)

Population: All participants treated had at least 1 post-dose PK result; therefore, all participants were included in the PK analysis population. One participant had an interrupted IV infusion of Palivizumab but received the complete dose of 8 mg/kg.

ArmMeasureValue (MEDIAN)
Open-label Palivizumab (Part 1)Tmax0.90 hours
Double-blind Palivizumab (Synagis™) (Part 2)Tmax0.92 hours
Secondary

Total Number of Tissues Used by Participants

Nasal Discharge Collection from Paper Tissues by means of the total number of tissues used.

Time frame: From Day 1 to Day 12 in Part 2

Population: Evaluable population

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)Total Number of Tissues Used by Participants32.04 tissuesStandard Error 42.74
Double-blind Placebo (Part 2)Total Number of Tissues Used by Participants20.38 tissuesStandard Error 21.88
Secondary

Total Symptom Score (TSS)-Time Curve (AUC) Collected Daily in the Participant Symptom Diary Card

Mean TSS values (collected daily in the symptom diary card) over time. Symptoms were collected using the hVIVO (services provider) symptom diary card. Several symptoms (such as runny nose, sore throat, earache, etc) in the 13-item questionnaire were graded on a scale of 0-3 (grade 0: No symptoms; grade 1: just noticeable; grade 2: clearly bothersome from time to time but does not interfere with me doing my normal daily activities; grade 3: Quite bothersome most or all of the time, and it stops me participating in activities). Shortness of breath and wheeze have an additional grade 4: Symptoms at rest. The total symptom score (TSS) was determined as the sum of the symptom scores ranging from 0.0 (min) to 41(max) \[or a maximum of 41x11.33=464.67 depending on what the reviewer is asking\] using a 13-items self-reported diary card. 11.33 is the number of days symptom diary cards were included (Day +1 morning dairy card to Day 12 morning diary card). Higher scores mean worse outcome.

Time frame: From two days post viral challenge (Day 2) to the end of quarantine (Day 12) in Part 2 on nasal samples collected twice daily.

Population: Evaluable population

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)Total Symptom Score (TSS)-Time Curve (AUC) Collected Daily in the Participant Symptom Diary Card13.84 Total Symptom Score scale-points*dayStandard Error 14.72
Double-blind Placebo (Part 2)Total Symptom Score (TSS)-Time Curve (AUC) Collected Daily in the Participant Symptom Diary Card7.27 Total Symptom Score scale-points*dayStandard Error 9.03
Secondary

Total Weight of Nasal Discharge Produced

Nasal Discharge Collection from Paper Tissues by means of the total weight of nasal discharge produced.

Time frame: From Day 1 to Day 12 in Part 2

Population: Evaluable population

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)Total Weight of Nasal Discharge Produced22.23 gStandard Error 41.52
Double-blind Placebo (Part 2)Total Weight of Nasal Discharge Produced7.66 gStandard Error 14.92
Secondary

Viral Shedding of RSV-A Memphis 37b in Nasal Samples in Terms of Duration, for Double-blind Palivizumab or Placebo (Part 2).

Estimation of the duration of viral shedding by the number of days with quantifiable qRT-PCR measurements in nasal samples starting 2 days post viral challenge (Day 2) up to the end of quarantine.

Time frame: From Day 2 to Day 12 in Part 2

Population: Evaluable population

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)Viral Shedding of RSV-A Memphis 37b in Nasal Samples in Terms of Duration, for Double-blind Palivizumab or Placebo (Part 2).2.84 daysStandard Deviation 3.01
Double-blind Placebo (Part 2)Viral Shedding of RSV-A Memphis 37b in Nasal Samples in Terms of Duration, for Double-blind Palivizumab or Placebo (Part 2).2.61 daysStandard Deviation 2.98
Secondary

Viral Shedding of RSV-A Memphis 37b in Nasal Samples in Terms of Peak Viral Load, for Double-blind Palivizumab or Placebo (Part 2).

Peak viral load of RSV-A Memphis 37b as defined by the maximum viral load determined by quantifiable qRT PCR measurements in nasal samples starting 2 days post viral challenge (Day 2) up to the end of quarantine.

Time frame: From Day 2 to Day 12 in Part 2

Population: Evaluable population

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)Viral Shedding of RSV-A Memphis 37b in Nasal Samples in Terms of Peak Viral Load, for Double-blind Palivizumab or Placebo (Part 2).3.66 Log10 copies/mLStandard Deviation 2.42
Double-blind Placebo (Part 2)Viral Shedding of RSV-A Memphis 37b in Nasal Samples in Terms of Peak Viral Load, for Double-blind Palivizumab or Placebo (Part 2).3.11 Log10 copies/mLStandard Deviation 2.65
p-value: 0.4868Wilcoxon (Mann-Whitney)
Secondary

Viral Shedding of RSV-A Memphis 37b in Nasal Samples in Terms of Time to Peak Viral Load, for Double-blind Palivizumab or Placebo (Part 2).

Estimation of the duration of viral shedding by the time to peak viral load of RSV by quantifiable qRT-PCR.

Time frame: From Day 2 to Day 12 in Part 2

Population: Evaluable population

ArmMeasureValue (MEAN)Dispersion
Open-label Palivizumab (Part 1)Viral Shedding of RSV-A Memphis 37b in Nasal Samples in Terms of Time to Peak Viral Load, for Double-blind Palivizumab or Placebo (Part 2).7.21 daysStandard Deviation 2.98
Double-blind Placebo (Part 2)Viral Shedding of RSV-A Memphis 37b in Nasal Samples in Terms of Time to Peak Viral Load, for Double-blind Palivizumab or Placebo (Part 2).7.03 daysStandard Deviation 2.35

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026