Efficacy, Pharmacokinetics, and Safety of Presatovir in Hospitalized Adults With Respiratory Syncytial Virus (RSV) Infection

Study Overview
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Brief Summary
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The primary objective of this study is to evaluate the effects of presatovir on respiratory syncytial virus (RSV) viral load in RSV-positive adults who have been hospitalized with acute respiratory infectious symptoms. Participants will receive 1 dose of presatovir on Day 1 and followed for 27 days postdose. Nasal swabs will be collected at each study visit (excluding Day 28) and assayed for change in viral load as the primary endpoint.

Official Title
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A Phase 2b, Randomized, Double-Blind, Placebo-Controlled Multi-Center Study Evaluating Antiviral Effects, Pharmacokinetics, Safety, and Tolerability of GS-5806 in Hospitalized Adults With Respiratory Syncytial Virus (RSV) Infection

Conditions
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Respiratory Syncytial Virus Infection

Intervention / Treatment
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* Drug: Presatovir
* Drug: Presatovir placebo


Participation Criteria
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Eligibility Criteria
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Key Inclusion Criteria: Current inpatient New onset of acute respiratory infectious symptoms, or acute worsening of chronic symptoms related to ongoing respiratory disease for ≤ 5 days prior to screening: Upper respiratory tract symptoms: nasal congestion, runny nose, sore throat, or earache Lower respiratory tract symptoms: cough, sputum production, wheezing, dyspnea, or chest tightness Documented to be RSV-positive at the current admission within 72 hours of screening, or as evaluated at screening Key Exclusion Criteria: Related to concomitant or previous medication use: Use of oral prednisone or other corticosteroid equivalent to: > 20 mg/day for > 14 days prior to screening is not permitted. > 20 mg/day for ≤ 14 days, including corticosteroids received during current hospitalization (ie, bolus doses), is permitted. ≤ 20 mg/day, regardless of duration, is permitted. Individuals taking a moderate or strong cytochrome P450 enzyme (CYP) inducer including but not limited to rifampin, St John's Wort, carbamazepine, phenytoin, efavirenz, bosentan, etracirine, modafinil, and nafcillin within 2 weeks prior to the first dose of study drug Related to medical history: Pregnant, breastfeeding, or lactating females Individuals requiring > 50% supplemental oxygen (while the individual is awake) at screening Individuals with a Clinical Frailty Scale (CFS) > 7 at Baseline Known significant abnormality altering the anatomy of the nose or nasopharynx that in, the opinion of the investigator, will preclude obtaining adequate nasal swab sampling in either nasal passage Waiting for or recently (within the past 12 months) received a bone marrow, stem cell, or solid organ transplant, or who have received radiation or chemotherapy within 12 months prior to Screening Individuals with HIV/AIDS and a known CD4 count < 200 cells/uL History of severe dementia or Alzheimer's disease History of drug and/or alcohol abuse that, in the opinion of the investigator, may prevent adherence to study activities Related to medical condition at screening: Influenza-positive as determined by local diagnostic test Known Middle East Respiratory Syndrome coronavirus (MERS-CoV) infection or known coinfection with other coronavirus Use of mechanical ventilation during the current admission, not including noninvasive ventilation Clinically significant bacteremia or fungemia that has not been adequately treated prior to Screening, as determined by the investigator Inadequate treatment of confirmed bacterial, fungal, or non-RSV pneumonia, as determined by the investigator Excessive nausea/vomiting at admission, as determined by the investigator, that precludes administration of an orally administered study drug Related to allergies: Known allergy to components of the study drug (microcrystalline cellulose, mannitol, croscarmellose sodium, magnesium stearate, polyvinyl alcohol, titanium dioxide, polyethylene glycol and talc) Documented history of acute (anaphylaxis) or delayed (Stevens-Johnson syndrome or epidermal necrolysis) allergy to sulfa drugs Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Presatovir<br>Participants will receive a single dose of presatovir. | Drug: Presatovir<br>* Presatovir 200 mg (4 x 50 mg tablets) administered orally<br>* Other names: GS-5806;|
| Placebo Comparator: Presatovir placebo<br>Participants will receive a single dose of presatovir placebo. | Drug: Presatovir placebo<br>* Presatovir placebo tablets administered orally<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time-Weighted Average Change in Respiratory Syncytial Viral (RSV) Load From Baseline to Day 5 | The time-weighted average change, often referred to as the DAVG, provides the average viral burden change from baseline. The mean values presented were calculated using the ANCOVA model and are adjusted for baseline value and stratification factor. | Baseline to Day 5 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time-weighted Average Change in the Flu-PRO Score From Baseline to Day 5 | The Flu-PRO is a patient-reported outcome questionnaire utilized as a standardized method for evaluating symptoms of influenza. Flu-PRO Score was calculated as the mean of 38 individual scores. Individual scores ranged from 0 (no symptoms) to 4 (worst symptoms). The mean values presented were calculated using the ANCOVA model and are adjusted for baseline value and stratification factor. | Baseline to Day 5 | 
| Number of Hospitalization-Free Days Following Presatovir Administration |  | Up to Day 28 | 
| Rate of Unplanned Medical Encounters | The adjusted rate of unplanned medical encounters (clinic visits, emergency room visits, urgent care visits, and rehospitalizations) related to a respiratory illness after initial hospital discharge through Day 28 will be assessed. Event rate was calculated as the total number of unplanned medical encounters divided by the total number of participants. The mean values presented were adjusted for stratification factor. | Up to Day 28 |