Trial Outcomes & Findings for The Effectiveness of CD388 to Prevent Flu in an Influenza Challenge Model in Healthy Adults (NCT NCT05523089)

Results Overview

Evaluation of the prophylactic effect of CD388, when compared to placebo, on VL-AUC of influenza challenge virus as determined by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) on nasal samples starting 1 day post viral challenge.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

59 participants

Primary outcome timeframe

Day 1 (evening [pm]); Days 2, 3, 4, 5, 6, and 7 (morning [am] and pm); Day 8 (am)

Results posted on

2024-09-19

Participant Flow

Up to 168 participants in up to 2 cohorts were planned for enrollment in the study. Due to low participant eligibility, the randomization schedule was changed in Cohort 1 after the first quarantine group to only randomize participants to the 150 mg CD388 and placebo arms. With only 2 participants in the 50 mg CD388 arm, safety and demographic data only have been reported. Based on data from the planned interim analysis of Cohort 1, a decision was made to not proceed with Cohort 2.

Participant milestones

Participant milestones
Measure	Placebo Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	50 mg CD388 Up to 30 participants randomized to receive a single dose of 50 milligrams (mg) CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Overall Study STARTED	29	2	28
Overall Study COMPLETED	27	2	28
Overall Study NOT COMPLETED	2	0	0

Reasons for withdrawal

Reasons for withdrawal
Measure	Placebo Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	50 mg CD388 Up to 30 participants randomized to receive a single dose of 50 milligrams (mg) CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Overall Study Withdrawal by Subject	1	0	0
Overall Study Lost to Follow-up	1	0	0

Baseline Characteristics

The Effectiveness of CD388 to Prevent Flu in an Influenza Challenge Model in Healthy Adults

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Placebo n=29 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	50 mg CD388 n=2 Participants Up to 30 participants randomized to receive a single dose of 50 milligrams (mg) CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	Total n=59 Participants Total of all reporting groups
Age, Continuous	31.00 years n=5 Participants	27.50 years n=7 Participants	32.00 years n=5 Participants	31.00 years n=4 Participants
Sex: Female, Male Female	9 Participants n=5 Participants	0 Participants n=7 Participants	13 Participants n=5 Participants	22 Participants n=4 Participants
Sex: Female, Male Male	20 Participants n=5 Participants	2 Participants n=7 Participants	15 Participants n=5 Participants	37 Participants n=4 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	29 Participants n=5 Participants	2 Participants n=7 Participants	28 Participants n=5 Participants	59 Participants n=4 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Asian	2 Participants n=5 Participants	1 Participants n=7 Participants	2 Participants n=5 Participants	5 Participants n=4 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Black or African American	1 Participants n=5 Participants	0 Participants n=7 Participants	3 Participants n=5 Participants	4 Participants n=4 Participants
Race (NIH/OMB) White	24 Participants n=5 Participants	1 Participants n=7 Participants	23 Participants n=5 Participants	48 Participants n=4 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Unknown or Not Reported	2 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	2 Participants n=4 Participants
Region of Enrollment United Kingdom	29 participants n=5 Participants	2 participants n=7 Participants	28 participants n=5 Participants	59 participants n=4 Participants
Weight	72.90 kg n=5 Participants	72.40 kg n=7 Participants	75.60 kg n=5 Participants	75.20 kg n=4 Participants
Height	1.72 meters (m) n=5 Participants	1.70 meters (m) n=7 Participants	1.77 meters (m) n=5 Participants	1.74 meters (m) n=4 Participants
Body Mass Index (BMI)	25.00 kg/m^2 n=5 Participants	25.15 kg/m^2 n=7 Participants	24.60 kg/m^2 n=5 Participants	24.90 kg/m^2 n=4 Participants

PRIMARY outcome

Timeframe: Day 1 (evening [pm]); Days 2, 3, 4, 5, 6, and 7 (morning [am] and pm); Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the prophylactic effect of CD388, when compared to placebo, on VL-AUC of influenza challenge virus as determined by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) on nasal samples starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Mean Area Under the Viral Load-Time Curve (VL-AUC) After Influenza Viral Challenge	16.09 log[10] copies/milliliter (mL)*hour Standard Deviation 11.86	10.70 log[10] copies/milliliter (mL)*hour Standard Deviation 8.01	—

PRIMARY outcome

Timeframe: Day 1 (evening [pm]); Days 2, 3, 4, 5, 6, and 7 (morning [am] and pm); Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the prophylactic effect of CD388, when compared to placebo, on VL-AUC of influenza challenge virus as determined by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) on nasal samples starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Median Area Under the Viral Load-Time Curve (VL-AUC) After Influenza Viral Challenge	8.52 log[10] copies/mL*hour Interval 6.4 to 39.8	6.40 log[10] copies/mL*hour Interval 6.4 to 29.9	—

SECONDARY outcome

Timeframe: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the peak (i.e., maximum) viral load of influenza as determined by quantifiable qRT-PCR measurements in nasal samples starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Mean Peak Viral Load by qRT-PCR After Influenza Viral Challenge	4.28 log[10] copies/mL Standard Deviation 2.94	2.84 log[10] copies/mL Standard Deviation 2.40	—

SECONDARY outcome

Timeframe: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the peak (i.e., maximum) viral load of influenza as determined by quantifiable qRT-PCR measurements in nasal samples starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Median Peak Viral Load by qRT-PCR After Influenza Viral Challenge	3.79 log[10] copies/mL Interval 1.0 to 8.5	0.97 log[10] copies/mL Interval 0.9 to 7.5	—

SECONDARY outcome

Timeframe: From Day 1 (pm) until the first confirmed undetectable assessment after peak measurement, assessed up to Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint. NOTE: Participants without a detectable qRT-PCR value were excluded from the analysis.

Evaluation of the effect of CD388, when compared to placebo, on the time (in hours, as estimated using the Kaplan-Meier method) to confirmed negative test for influenza as determined by quantifiable qRT-PCR measurements in nasal samples starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=19 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=12 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Time to Confirmed Negative Test by qRT-PCR After Influenza Viral Challenge 75th Percentile	158.3 hours Interval 134.1 to Some values were not computable due to the lack of an event {i.e., the first result equal to not detected (less than the Lower Level of Detection \[\<LLOD\]) after peak measure} at the assessed timepoint.	131.7 hours Interval 72.4 to Some values were not computable due to the lack of an event {i.e., the first result equal to not detected (less than the Lower Level of Detection \[\<LLOD\]) after peak measure} at the assessed timepoint.	—
Time to Confirmed Negative Test by qRT-PCR After Influenza Viral Challenge 25th Percentile	61.9 hours Interval 14.7 to 120.3	66.7 hours Interval 24.3 to 72.4	—
Time to Confirmed Negative Test by qRT-PCR After Influenza Viral Challenge Median	134.1 hours Interval 61.9 to Some values were not computable due to the lack of an event {i.e., the first result equal to not detected (less than the Lower Level of Detection \[\<LLOD\]) after peak measure} at the assessed timepoint.	79.4 hours Interval 24.4 to 143.1	—

SECONDARY outcome

Timeframe: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on VL-AUC of influenza challenge virus as determined by viral culture on nasal samples starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Mean Area Under the Viral Load-Time Curve (VL-AUC) by Viral Culture After Influenza Viral Challenge	5.82 log[10] copies/mL*hour Standard Deviation 3.70	3.95 log[10] copies/mL*hour Standard Deviation 1.57	—

SECONDARY outcome

Timeframe: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on VL-AUC of influenza challenge virus as determined by viral culture on nasal samples starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Median Area Under the Viral Load-Time Curve (VL-AUC) by Viral Culture After Influenza Viral Challenge	3.29 log[10] copies/mL*hour Interval 3.2 to 14.4	3.29 log[10] copies/mL*hour Interval 3.2 to 9.7	—

SECONDARY outcome

Timeframe: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the peak (i.e., maximum) viral load of influenza as determined by quantitative viral culture measurements in nasal samples starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Mean Peak Viral Load by Viral Culture After Influenza Viral Challenge	2.13 log[10] copies/mL Standard Deviation 2.10	1.07 log[10] copies/mL Standard Deviation 1.18	—

SECONDARY outcome

Timeframe: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the peak (i.e., maximum) viral load of influenza as determined by quantitative viral culture measurements in nasal samples starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Median Peak Viral Load by Viral Culture After Influenza Viral Challenge	0.50 log[10] copies/mL Interval 0.5 to 5.5	0.50 log[10] copies/mL Interval 0.5 to 4.5	—

SECONDARY outcome

Timeframe: From Day 1 (pm) until the first confirmed undetectable assessment after peak measurement, assessed up to Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint. NOTE: Participants without a detectable viral culture value were excluded from the analysis.

Evaluation of the effect of CD388, when compared to placebo, on the time (in hours, as estimated using the Kaplan-Meier method) to confirmed negative test for influenza as determined by quantifiable viral culture measurements in nasal samples starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=11 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=6 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Time to Confirmed Negative Test by Viral Culture After Influenza Viral Challenge 25th Percentile	71.4 hours Interval 47.2 to 85.9	62.3 hours Interval 24.3 to 85.9	—
Time to Confirmed Negative Test by Viral Culture After Influenza Viral Challenge 75th Percentile	110.1 hours Interval 85.9 to Some values were not computable due to the lack of an event {i.e., the first result equal to not detected (less than the Lower Level of Detection \[\<LLOD\]) after peak measure} at the assessed timepoint.	86.0 hours Interval 62.3 to Some values were not computable due to the lack of an event {i.e., the first result equal to not detected (less than the Lower Level of Detection \[\<LLOD\]) after peak measure} at the assessed timepoint.	—
Time to Confirmed Negative Test by Viral Culture After Influenza Viral Challenge Median	85.9 hours Interval 47.5 to 110.1	78.7 hours Interval 24.3 to Some values were not computable due to the lack of an event {i.e., the first result equal to not detected (less than the Lower Level of Detection \[\<LLOD\]) after peak measure} at the assessed timepoint.	—

SECONDARY outcome

Timeframe: Three (3) times per day, at the same time each day (±1 hour), on Days 1, 2, 3, 4, 5, 6, and 7; and on Day 8 (am only)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on TSS-AUC as measured by graded symptom scoring system (participant completed symptom diary card) collected 3 times daily starting 1 day post viral challenge. At each assessment, the participant provides scores from 0 to 3 for a list of 13 symptoms (runny nose, stuffy nose, sneezing, sore throat, earache, malaise/tiredness, headache, muscle and/or joint ache, chilliness/feverishness, cough, chest tightness, shortness of breath, and wheeze). Grade 0: no symptoms; grade 1: just noticeable; grade 2: clearly bothersome from time to time but does not interfere with normal daily activities; grade 3: quite bothersome most or all the time and stops participation in activities. An individual Total Symptom Score (TSS) is derived at each assessment of the diary card as the sum of the scores given to the 13 symptoms on that symptom score card, resulting in possible TSS values from 0 to 39.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Mean Area Under the Total Clinical Symptoms Score-Time Curve (TSS-AUC) After Influenza Viral Challenge	7.66 TSS points*day Standard Deviation 14.13	2.22 TSS points*day Standard Deviation 4.86	—

SECONDARY outcome

Timeframe: Three (3) times per day, at the same time each day (±1 hour), on Days 1, 2, 3, 4, 5, 6, and 7; and on Day 8 (am only)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on TSS-AUC as measured by graded symptom scoring system (participant completed symptom diary card) collected 3 times daily starting 1 day post viral challenge. At each assessment, the participant provides scores from 0 to 3 for a list of 13 symptoms (runny nose, stuffy nose, sneezing, sore throat, earache, malaise/tiredness, headache, muscle and/or joint ache, chilliness/feverishness, cough, chest tightness, shortness of breath, and wheeze). Grade 0: no symptoms; grade 1: just noticeable; grade 2: clearly bothersome from time to time but does not interfere with normal daily activities; grade 3: quite bothersome most or all the time and stops participation in activities. An individual Total Symptom Score (TSS) is derived at each assessment of the diary card as the sum of the scores given to the 13 symptoms on that symptom score card, resulting in possible TSS values from 0 to 39.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Median Area Under the Total Clinical Symptoms Score-Time Curve (TSS-AUC) After Influenza Viral Challenge	0.45 TSS points*day Interval 0.0 to 48.3	0.86 TSS points*day Interval 0.0 to 25.2	—

SECONDARY outcome

Timeframe: Three (3) times per day, at the same time each day (±1 hour), on Days 1, 2, 3, 4, 5, 6, and 7; and on Day 8 (am only)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the peak (i.e., maximum) TSS score as measured by graded symptom scoring system (participant completed symptom diary card) collected 3 times daily starting 1 day post viral challenge. At each assessment, the participant provides scores from 0 to 3 for a list of 13 symptoms (runny nose, stuffy nose, sneezing, sore throat, earache, malaise/tiredness, headache, muscle and/or joint ache, chilliness/feverishness, cough, chest tightness, shortness of breath, and wheeze). Grade 0: no symptoms; grade 1: just noticeable; grade 2: clearly bothersome from time to time but does not interfere with normal daily activities; grade 3: quite bothersome most or all the time and stops participation in activities. An individual Total Symptom Score (TSS) is derived at each assessment of the diary card as the sum of the scores given to the 13 symptoms on that symptom score card, resulting in possible TSS values from 0 to 39.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Mean Peak Total Clinical Symptoms Score (TSS) After Influenza Viral Challenge	3.54 total symptom score Standard Deviation 5.34	1.79 total symptom score Standard Deviation 3.12	—

SECONDARY outcome

Timeframe: Three (3) times per day, at the same time each day (±1 hour), on Days 1, 2, 3, 4, 5, 6, and 7; and on Day 8 (am only)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the peak (i.e., maximum) TSS score as measured by graded symptom scoring system (participant completed symptom diary card) collected 3 times daily starting 1 day post viral challenge. At each assessment, the participant provides scores from 0 to 3 for a list of 13 symptoms (runny nose, stuffy nose, sneezing, sore throat, earache, malaise/tiredness, headache, muscle and/or joint ache, chilliness/feverishness, cough, chest tightness, shortness of breath, and wheeze). Grade 0: no symptoms; grade 1: just noticeable; grade 2: clearly bothersome from time to time but does not interfere with normal daily activities; grade 3: quite bothersome most or all the time and stops participation in activities. An individual Total Symptom Score (TSS) is derived at each assessment of the diary card as the sum of the scores given to the 13 symptoms on that symptom score card, resulting in possible TSS values from 0 to 39.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Median Peak Total Clinical Symptoms Score (TSS) After Influenza Viral Challenge	1.00 total symptom score Interval 0.0 to 21.0	1.00 total symptom score Interval 0.0 to 16.0	—

SECONDARY outcome

Timeframe: From Day 1 up to Day 8

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the peak (i.e., maximum) daily symptom score (i.e., individual maximum daily sum of symptom score) as measured by graded symptom scoring system (participant completed symptom diary card) collected 3 times daily starting 1 day post viral challenge. At each assessment, the participant provides scores from 0 to 3 for a list of 13 symptoms (runny nose, stuffy nose, sneezing, sore throat, earache, malaise/tiredness, headache, muscle and/or joint ache, chilliness/feverishness, cough, chest tightness, shortness of breath, and wheeze). Grade 0: no symptoms; grade 1: just noticeable; grade 2: clearly bothersome from time to time but does not interfere with normal daily activities; grade 3: quite bothersome most or all the time and stops participation in activities. An individual Total Symptom Score (TSS) is derived at each assessment as the sum of the scores given to the 13 symptoms, giving possible TSS values from 0 to 39.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Mean Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 2	2.29 total symptom score Standard Deviation 4.60	0.75 total symptom score Standard Deviation 2.12	—
Mean Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 3	2.79 total symptom score Standard Deviation 5.10	1.25 total symptom score Standard Deviation 3.15	—
Mean Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 6	0.79 total symptom score Standard Deviation 1.91	0.39 total symptom score Standard Deviation 0.69	—
Mean Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 7	0.43 total symptom score Standard Deviation 1.53	0.07 total symptom score Standard Deviation 0.26	—
Mean Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 1	0.64 total symptom score Standard Deviation 1.50	0.46 total symptom score Standard Deviation 0.84	—
Mean Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 4	2.11 total symptom score Standard Deviation 3.83	0.82 total symptom score Standard Deviation 1.85	—
Mean Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 5	1.07 total symptom score Standard Deviation 2.12	0.36 total symptom score Standard Deviation 0.87	—
Mean Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 8 Discharge	0.15 total symptom score Standard Deviation 0.60	0.11 total symptom score Standard Deviation 0.42	—

SECONDARY outcome

Timeframe: From Day 1 up to Day 8

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the peak (i.e., maximum) daily symptom score (i.e., individual maximum daily sum of symptom score) as measured by graded symptom scoring system (participant completed symptom diary card) collected 3 times daily starting 1 day post viral challenge. At each assessment, the participant provides scores from 0 to 3 for a list of 13 symptoms (runny nose, stuffy nose, sneezing, sore throat, earache, malaise/tiredness, headache, muscle and/or joint ache, chilliness/feverishness, cough, chest tightness, shortness of breath, and wheeze). Grade 0: no symptoms; grade 1: just noticeable; grade 2: clearly bothersome from time to time but does not interfere with normal daily activities; grade 3: quite bothersome most or all the time and stops participation in activities. An individual Total Symptom Score (TSS) is derived at each assessment as the sum of the scores given to the 13 symptoms, giving possible TSS values from 0 to 39.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Median Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 2	0.00 total symptom score Interval 0.0 to 17.0	0.00 total symptom score Interval 0.0 to 11.0	—
Median Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 3	0.00 total symptom score Interval 0.0 to 21.0	0.00 total symptom score Interval 0.0 to 16.0	—
Median Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 4	0.00 total symptom score Interval 0.0 to 14.0	0.00 total symptom score Interval 0.0 to 8.0	—
Median Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 6	0.00 total symptom score Interval 0.0 to 9.0	0.00 total symptom score Interval 0.0 to 2.0	—
Median Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 7	0.00 total symptom score Interval 0.0 to 8.0	0.00 total symptom score Interval 0.0 to 1.0	—
Median Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 8 Discharge	0.00 total symptom score Interval 0.0 to 3.0	0.00 total symptom score Interval 0.0 to 2.0	—
Median Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 1	0.00 total symptom score Interval 0.0 to 7.0	0.00 total symptom score Interval 0.0 to 3.0	—
Median Individual Peak Daily Total Clinical Symptoms Score After Influenza Viral Challenge Quarantine Day 5	0.00 total symptom score Interval 0.0 to 8.0	0.00 total symptom score Interval 0.0 to 4.0	—

SECONDARY outcome

Timeframe: Starting Day 1, from the time of peak daily symptom score until the time of returning to baseline score, up to Day 8

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint. NOTE: Participants who only had a baseline TSS were excluded from the analysis.

Evaluation of the effect of CD388, when compared to placebo, on the time (in hours, as estimated using the Kaplan-Meier method) to symptom resolution (i.e., first time with Total Symptom Score \[TSS\] equal to the TSS at baseline after which no further increase above the baseline TSS was observed) as measured by graded daily symptom scoring system (participant completed symptom diary card) collected 3 times daily starting 1 day post viral challenge. An individual TSS is derived at each assessment of the diary card as the sum of the scores given to the 13 symptoms on that symptom score card, resulting in possible TSS values from 0 to 39.

Outcome measures

Outcome measures
Measure	Placebo n=19 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=18 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Time to Symptom Resolution After Influenza Viral Challenge 25th Percentile	8.4 hours Interval 6.9 to 31.1	23.3 hours Interval 6.7 to 54.3	—
Time to Symptom Resolution After Influenza Viral Challenge Median	41.5 hours Interval 8.4 to 72.7	74.8 hours Interval 23.3 to 96.2	—
Time to Symptom Resolution After Influenza Viral Challenge 75th Percentile	78.7 hours Interval 41.5 to Some values were not computable due to the lack of an event at the assessed timepoint.	133.5 hours Interval 84.4 to Some values were not computable due to the lack of an event at the assessed timepoint.	—

SECONDARY outcome

Timeframe: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the number of participants with qRT-PCR-confirmed influenza infection, defined as 2 quantifiable (≥ lower limit of quantification \[LLOQ\]) qRT-PCR measurements (reported on 2 or more independent nasal samples over 2 days), starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Number of Participants With qRT-PCR-Confirmed Influenza Infection After Influenza Viral Challenge No qRT-PCR-confirmed Influenza Infection	14 Participants	22 Participants	—
Number of Participants With qRT-PCR-Confirmed Influenza Infection After Influenza Viral Challenge qRT-PCR-confirmed Influenza Infection	14 Participants	6 Participants	—

SECONDARY outcome

Timeframe: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the percentage of participants with qRT-PCR-confirmed influenza infection, defined as 2 quantifiable (≥ lower limit of quantification \[LLOQ\]) qRT-PCR measurements (reported on 2 or more independent nasal samples over 2 days), starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Percentage of Participants With qRT-PCR-Confirmed Influenza Infection After Influenza Viral Challenge No qRT-PCR-confirmed Influenza Infection	50.0 percentage of participants Interval 30.6 to 69.4	78.6 percentage of participants Interval 59.0 to 91.7	—
Percentage of Participants With qRT-PCR-Confirmed Influenza Infection After Influenza Viral Challenge qRT-PCR-confirmed Influenza Infection	50.0 percentage of participants Interval 30.6 to 69.4	21.4 percentage of participants Interval 8.3 to 41.0	—

SECONDARY outcome

Timeframe: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the number of participants with at least 1 positive quantitative (≥LLOQ) cell culture measurement in nasal samples starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Number of Participants With at Least One Positive Quantitative (≥LLOQ) Cell Culture After Influenza Viral Challenge No Positive Quantitative (≥LLOQ) Cell Culture	17 Participants	22 Participants	—
Number of Participants With at Least One Positive Quantitative (≥LLOQ) Cell Culture After Influenza Viral Challenge At Least 1 Positive Quantitative (≥LLOQ) Cell Culture	11 Participants	6 Participants	—

SECONDARY outcome

Timeframe: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the percentage of participants with at least 1 positive quantitative (≥LLOQ) cell culture measurement in nasal samples starting 1 day post viral challenge.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Percentage of Participants With at Least One Positive Quantitative (≥LLOQ) Cell Culture After Influenza Viral Challenge No Positive Quantitative (≥LLOQ) Cell Culture	60.7 percentage of participants Interval 40.6 to 78.5	78.6 percentage of participants Interval 59.0 to 91.7	—
Percentage of Participants With at Least One Positive Quantitative (≥LLOQ) Cell Culture After Influenza Viral Challenge At Least 1 Positive Quantitative (≥LLOQ) Cell Culture	39.3 percentage of participants Interval 21.5 to 59.4	21.4 percentage of participants Interval 8.3 to 41.0	—

SECONDARY outcome

Timeframe: • For qRT-PCR measurements: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am) • For TSS measurements: Three (3) times per day, at the same time each day (±1 hour), on Days 1, 2, 3, 4, 5, 6, and 7; and on Day 8 (am only)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the number of participants with qRT-PCR-confirmed symptomatic influenza infection starting 1 day post viral challenge, defined as: * RT-PCR-confirmed influenza infection (2 quantifiable \[≥LLOQ\] qRT-PCR measurements \[reported on 2 or more independent nasal samples over 2 days\]), AND * TSS score ≥2 at any single time point (i.e., any individual symptom diary card for which the sum of symptom scores is ≥2; e.g., at a minimum, ≥1 symptom of grade ≥2, or ≥2 symptoms of grade ≥1), as measured by graded symptom scoring system (participant completed symptom diary card) collected 3 times daily.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Number of Participants With qRT-PCR-Confirmed Symptomatic Influenza Infection After Influenza Viral Challenge No qRT-PCR-confirmed Symptomatic Influenza Infection	19 Participants	24 Participants	—
Number of Participants With qRT-PCR-Confirmed Symptomatic Influenza Infection After Influenza Viral Challenge qRT-PCR-confirmed Symptomatic Influenza Infection	9 Participants	4 Participants	—

SECONDARY outcome

Timeframe: • For qRT-PCR measurements: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am) • For TSS measurements: Three (3) times per day, at the same time each day (±1 hour), on Days 1, 2, 3, 4, 5, 6, and 7; and on Day 8 (am only)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the percentage of participants with qRT-PCR-confirmed symptomatic influenza infection starting 1 day post viral challenge, defined as: * RT-PCR-confirmed influenza infection (2 quantifiable \[≥LLOQ\] qRT-PCR measurements \[reported on 2 or more independent nasal samples over 2 days\]), AND * TSS score ≥2 at any single time point (i.e., any individual symptom diary card for which the sum of symptom scores is ≥2; e.g., at a minimum, ≥1 symptom of grade ≥2, or ≥2 symptoms of grade ≥1), as measured by graded symptom scoring system (participant completed symptom diary card) collected 3 times daily.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Percentage of Participants With qRT-PCR-Confirmed Symptomatic Influenza Infection After Influenza Viral Challenge No qRT-PCR-confirmed Symptomatic Influenza Infection	67.9 percentage of participants Interval 47.6 to 84.1	85.7 percentage of participants Interval 67.3 to 96.0	—
Percentage of Participants With qRT-PCR-Confirmed Symptomatic Influenza Infection After Influenza Viral Challenge qRT-PCR-confirmed Symptomatic Influenza Infection	32.1 percentage of participants Interval 15.9 to 52.4	14.3 percentage of participants Interval 4.0 to 32.7	—

SECONDARY outcome

Timeframe: • For qRT-PCR measurements: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am) • For symptom scoring measurements: Three (3) times per day, at the same time each day (±1 hour), on Days 1, 2, 3, 4, 5, 6, and 7; and on Day 8 (am only)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the number of participants with qRT-PCR-confirmed moderately severe symptomatic influenza infection starting 1 day post viral challenge, defined as: * RT-PCR-confirmed influenza infection (2 quantifiable \[≥LLOQ\] qRT-PCR measurements \[reported on 2 or more independent nasal samples over 2 days\]), AND * One or more symptoms of grade ≥2 at a single time point (i.e., on any individual symptom card), as measured by graded symptom scoring system (participant completed symptom diary card) collected 3 times daily.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Number of Participants With qRT-PCR-Confirmed Moderately Severe Symptomatic Influenza Infection After Influenza Viral Challenge No qRT-PCR-confirmed Moderately Severe Symptomatic Influenza Infection	21 Participants	25 Participants	—
Number of Participants With qRT-PCR-Confirmed Moderately Severe Symptomatic Influenza Infection After Influenza Viral Challenge qRT-PCR-confirmed Moderately Severe Symptomatic Influenza Infection	7 Participants	3 Participants	—

SECONDARY outcome

Timeframe: • For qRT-PCR measurements: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am) • For symptom scoring measurements: Three (3) times per day, at the same time each day (±1 hour), on Days 1, 2, 3, 4, 5, 6, and 7; and on Day 8 (am only)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the percentage of participants with qRT-PCR-confirmed moderately severe symptomatic influenza infection starting 1 day post viral challenge, defined as: * RT-PCR-confirmed influenza infection (2 quantifiable \[≥LLOQ\] qRT-PCR measurements \[reported on 2 or more independent nasal samples over 2 days\]), AND * One or more symptoms of grade ≥2 at a single time point (i.e., on any individual symptom card), as measured by graded symptom scoring system (participant completed symptom diary card) collected 3 times daily.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Percentage of Participants With qRT-PCR-Confirmed Moderately Severe Symptomatic Influenza Infection After Influenza Viral Challenge No qRT-PCR-confirmed Moderately Severe Symptomatic Influenza Infection	75.0 percentage of participants Interval 55.1 to 89.3	89.3 percentage of participants Interval 71.8 to 97.7	—
Percentage of Participants With qRT-PCR-Confirmed Moderately Severe Symptomatic Influenza Infection After Influenza Viral Challenge qRT-PCR-confirmed Moderately Severe Symptomatic Influenza Infection	25.0 percentage of participants Interval 10.7 to 44.9	10.7 percentage of participants Interval 2.3 to 28.2	—

SECONDARY outcome

Timeframe: • For viral culture measurements: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am) • For TSS measurements: Three (3) times per day, at the same time each day (±1 hour), on Days 1, 2, 3, 4, 5, 6, and 7; and on Day 8 (am only)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the number of participants with culture laboratory-confirmed symptomatic influenza infection starting 1 day post viral challenge, defined as: * Lab-confirmed culturable influenza infection (1 quantifiable \[≥LLOQ\] cell culture measurement in nasal samples), AND * TSS score ≥2 at any single time point (i.e., any individual symptom diary card for which the sum of symptom scores is ≥2; e.g., at a minimum, ≥1 symptom of grade ≥2, or ≥2 symptoms of grade ≥1), as measured by graded symptom scoring system (participant completed symptom diary card) collected 3 times daily.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Number of Participants With Culture Lab-Confirmed Symptomatic Influenza Infection After Influenza Viral Challenge No Culture Lab-confirmed Symptomatic Influenza Infection	20 Participants	24 Participants	—
Number of Participants With Culture Lab-Confirmed Symptomatic Influenza Infection After Influenza Viral Challenge Culture Lab-confirmed Symptomatic Influenza Infection	8 Participants	4 Participants	—

SECONDARY outcome

Timeframe: • For viral culture measurements: Day 1 (pm); Days 2, 3, 4, 5, 6, and 7 (am and pm); Day 8 (am) • For TSS measurements: Three (3) times per day, at the same time each day (±1 hour), on Days 1, 2, 3, 4, 5, 6, and 7; and on Day 8 (am only)

Population: The Per-Protocol Population included all randomized participants who received at least 1 dose of study intervention and were challenged with the study virus, and who have a valid result for at least 80% of the planned qRT-PCR nasal samples from Day 1 (pm) up to Day 8 (am) (i.e., at least 11 out of 14), and who present no major deviations likely to impact the evaluation of the primary efficacy endpoint.

Evaluation of the effect of CD388, when compared to placebo, on the percentage of participants with culture laboratory-confirmed symptomatic influenza infection starting 1 day post viral challenge, defined as: * Lab-confirmed culturable influenza infection (1 quantifiable \[≥LLOQ\] cell culture measurement in nasal samples), AND * TSS score ≥2 at any single time point (i.e., any individual symptom diary card for which the sum of symptom scores is ≥2; e.g., at a minimum, ≥1 symptom of grade ≥2, or ≥2 symptoms of grade ≥1), as measured by graded symptom scoring system (participant completed symptom diary card) collected 3 times daily.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Percentage of Participants With Culture Lab-Confirmed Symptomatic Influenza Infection After Influenza Viral Challenge No Culture Lab-confirmed Symptomatic Influenza Infection	71.4 percentage of participants Interval 51.3 to 86.8	85.7 percentage of participants Interval 67.3 to 96.0	—
Percentage of Participants With Culture Lab-Confirmed Symptomatic Influenza Infection After Influenza Viral Challenge Culture Lab-confirmed Symptomatic Influenza Infection	28.6 percentage of participants Interval 13.2 to 48.7	14.3 percentage of participants Interval 4.0 to 32.7	—

SECONDARY outcome

Timeframe: From Day -5 (dosing) up to Day 0 (viral challenge)

Population: The Safety Population included all participants who received at least 1 dose of study intervention. Participants were analyzed according to the study intervention they received.

Evaluation of the occurrence of solicited AEs in participants dosed with CD388, when compared with placebo, from the time of SQ dosing up to the time of inoculation with the influenza challenge virus, based on the number of participants reporting any solicited AE. Solicited AEs are those predefined events relating to reactogenicity (pain, tenderness, erythema/redness, induration/swelling) for which participants were specifically questioned and which were noted by participants in a participant diary.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=2 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Occurrence of Solicited Adverse Events (AEs) From Subcutaneous (SQ) Dosing up to Viral Challenge - Number of Participants	0 Participants	0 Participants	1 Participants

SECONDARY outcome

Timeframe: From Day -5 (dosing) up to Day 0 (viral challenge)

Population: The Safety Population included all participants who received at least 1 dose of study intervention. Participants were analyzed according to the study intervention they received.

Evaluation of the occurrence of solicited AEs in participants dosed with CD388, when compared with placebo, from the time of SQ dosing up to the time of inoculation with the influenza challenge virus, based on the number of events reported. Solicited AEs are those predefined events relating to reactogenicity (pain, tenderness, erythema/redness, induration/swelling) for which participants were specifically questioned and which were noted by participants in a participant diary.

Outcome measures

Outcome measures
Measure	Placebo n=28 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=2 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Occurrence of Solicited Adverse Events (AEs) From Subcutaneous (SQ) Dosing up to Viral Challenge - Number of Events	0 events	0 events	1 events

SECONDARY outcome

Timeframe: From Day -5 (dosing) up to Day 28 (±3 days)

Population: The Safety Population included all participants who received at least 1 dose of study intervention. Participants were analyzed according to the study intervention they received.

Evaluation of the occurrence of unsolicited AEs in participants dosed with CD388, when compared with placebo, from the time of SQ dosing up to the time of the Day 28 follow-up visit, based on the number of participants for whom any AE is observed. Unsolicited AEs are any AEs observed by the participant or Principal Investigator (PI)/investigator which are not prelisted on a symptom diary card. Results are categorized by period: * Period 1 (from Day -5 dosing to just before challenge virus inoculation on Day 0) * Period 2 (from Day 0 challenge virus inoculation to actual discharge from the quarantine unit \[as scheduled on Day 8 or later at PI's decision\]) * Period 3 (from actual discharge from the quarantine unit to Day 28 (±3 days)

Outcome measures

Outcome measures
Measure	Placebo n=29 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=2 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Occurrence of Unsolicited AEs From SQ Dosing up to Day 28 Follow-up Visit - Number of Participants Periods 1 and 2	4 Participants	1 Participants	2 Participants
Occurrence of Unsolicited AEs From SQ Dosing up to Day 28 Follow-up Visit - Number of Participants Period 2	3 Participants	1 Participants	2 Participants
Occurrence of Unsolicited AEs From SQ Dosing up to Day 28 Follow-up Visit - Number of Participants Periods 2 and 3	10 Participants	1 Participants	11 Participants
Occurrence of Unsolicited AEs From SQ Dosing up to Day 28 Follow-up Visit - Number of Participants Period 3	8 Participants	1 Participants	9 Participants
Occurrence of Unsolicited AEs From SQ Dosing up to Day 28 Follow-up Visit - Number of Participants Period 1	1 Participants	1 Participants	0 Participants

SECONDARY outcome

Timeframe: From Day -5 (dosing) up to Day 28 (±3 days)

Population: The Safety Population included all participants who received at least 1 dose of study intervention. Participants were analyzed according to the study intervention they received.

Evaluation of the occurrence of unsolicited AEs in participants dosed with CD388, when compared with placebo, from the time of SQ dosing up to the time of the Day 28 follow-up visit, based on the number of events reported. Unsolicited AEs are any AEs observed by the participant or Principal Investigator (PI)/investigator which are not prelisted on a symptom diary card. Results are categorized by period: * Period 1 (from Day -5 dosing to just before challenge virus inoculation on Day 0) * Period 2 (from Day 0 challenge virus inoculation to actual discharge from the quarantine unit \[as scheduled on Day 8 or later at PI's decision\]) * Period 3 (from actual discharge from the quarantine unit to Day 28 (±3 days)

Outcome measures

Outcome measures
Measure	Placebo n=29 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=2 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Occurrence of Unsolicited AEs From SQ Dosing up to Day 28 Follow-up Visit - Number of Events Periods 1 and 2	4 events	2 events	2 events
Occurrence of Unsolicited AEs From SQ Dosing up to Day 28 Follow-up Visit - Number of Events Period 2	3 events	1 events	2 events
Occurrence of Unsolicited AEs From SQ Dosing up to Day 28 Follow-up Visit - Number of Events Periods 2 and 3	12 events	3 events	13 events
Occurrence of Unsolicited AEs From SQ Dosing up to Day 28 Follow-up Visit - Number of Events Period 3	9 events	2 events	11 events
Occurrence of Unsolicited AEs From SQ Dosing up to Day 28 Follow-up Visit - Number of Events Period 1	1 events	1 events	0 events

SECONDARY outcome

Timeframe: From Day -5 (dosing) up to Day 180 (±14 days)

Population: The Safety Population included all participants who received at least 1 dose of study intervention. Participants were analyzed according to the study intervention they received.

Evaluation of the occurrence of unsolicited AEs in participants dosed with CD388, when compared with placebo, from the time of SQ dosing up to the time of the Day 180 final follow-up visit, based on the number of participants for whom any AE was observed. Unsolicited AEs are any AEs observed by the participant or Principal Investigator (PI)/investigator which are not prelisted on a symptom diary card. Results are categorized by period: * Period 3 (from actual discharge from the quarantine unit to Day 28 \[±3 days\]) * Period 4 (from Day 28\[±3 days\] to the final follow-up visit \[Day 180 ±14 days\]) * Across All Periods (from Day -5 dosing to the final follow-up visit \[Day 180 ±14 days\])

Outcome measures

Outcome measures
Measure	Placebo n=29 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=2 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Occurrence of Unsolicited AEs From SQ Dosing up to the Final Follow-up Visit - Number of Participants Periods 3 and 4	16 Participants	1 Participants	19 Participants
Occurrence of Unsolicited AEs From SQ Dosing up to the Final Follow-up Visit - Number of Participants Period 4	9 Participants	0 Participants	14 Participants
Occurrence of Unsolicited AEs From SQ Dosing up to the Final Follow-up Visit - Number of Participants Period 3	8 Participants	1 Participants	9 Participants
Occurrence of Unsolicited AEs From SQ Dosing up to the Final Follow-up Visit - Number of Participants Across All Periods	19 Participants	1 Participants	21 Participants

SECONDARY outcome

Timeframe: From Day -5 (dosing) up to Day 180 (±14 days)

Population: The Safety Population included all participants who received at least 1 dose of study intervention. Participants were analyzed according to the study intervention they received.

Evaluation of the occurrence of unsolicited AEs in participants dosed with CD388, when compared with placebo, from the time of SQ dosing up to the time of the Day 180 final follow-up visit, based on the number of events reported. Unsolicited AEs are any AEs observed by the participant or Principal Investigator (PI)/investigator which are not prelisted on a symptom diary card. Results are categorized by period: * Period 3 (from actual discharge from the quarantine unit to Day 28 \[±3 days\]) * Period 4 (from Day 28\[±3 days\] to the final follow-up visit \[Day 180 ±14 days\]) * Across All Periods (from Day -5 dosing to the final follow-up visit \[Day 180 ±14 days\])

Outcome measures

Outcome measures
Measure	Placebo n=29 Participants Up to 30 participants randomized to receive a single dose of saline placebo, administered by subcutaneous (SQ) injection, prior to being inoculated with the influenza challenge virus Saline placebo: Sterile normal saline for injection	150 mg CD388 n=2 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection	150 mg CD388 n=28 Participants Up to 30 participants randomized to receive a single dose of 150 mg CD388, administered by SQ injection, prior to being inoculated with the influenza challenge virus CD388: CD388 liquid for injection
Occurrence of Unsolicited AEs From SQ Dosing up to the Final Follow-up Visit - Number of Events Period 3	9 events	2 events	11 events
Occurrence of Unsolicited AEs From SQ Dosing up to the Final Follow-up Visit - Number of Events Periods 3 and 4	21 events	2 events	32 events
Occurrence of Unsolicited AEs From SQ Dosing up to the Final Follow-up Visit - Number of Events Across All Periods	25 events	4 events	34 events
Occurrence of Unsolicited AEs From SQ Dosing up to the Final Follow-up Visit - Number of Events Period 4	12 events	0 events	21 events

Adverse Events

Placebo

Serious events: 0 serious events

Other events: 19 other events

Deaths: 0 deaths

50 mg CD388

Serious events: 0 serious events

Other events: 1 other events

Deaths: 0 deaths

150 mg CD388

Serious events: 0 serious events

Other events: 21 other events

Deaths: 0 deaths

All Arms

Serious events: 0 serious events

Other events: 41 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Additional Information

Chief Medical Officer

Cidara Therapeutics, Inc.

Phone: 858-888-7868

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place

Restriction type: OTHER