A Multicentre Study in Otherwise Healthy Infants and Toddlers Hospitalised For and Diagnosed With RSV Lower Respiratory Tract Infection to Evaluate the Safety, Tolerability, and Clinical Activity of ALX-0171

Study Overview
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Brief Summary
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The primary objective of the study is to investigate the safety and tolerability of ALX-0171. The secondary objectives are to evaluate the clinical effect of ALX-0171 and to explore the pharmacodynamics (PD) and the systemic pharmacokinetics (PK) of ALX-0171.

Official Title
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A Phase I/IIa Multicentre Study in Otherwise Healthy Infants and Toddlers Hospitalised For and Diagnosed With Respiratory Syncytial Virus Lower Respiratory Tract Infection, Consisting of an Open-label Lead-in Part Followed by a Double-blind, Placebo-controlled Part, to Evaluate the Safety, Tolerability and Clinical Activity of ALX-0171, Administered Via Inhalation, in Addition to Standard of Care.

Conditions
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Respiratory Syncytial Virus Infection

Intervention / Treatment
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* Biological: ALX-0171
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subject is otherwise healthy, but hospitalised for and clinically diagnosed with RSV LRTI (Lower Respiratory Tract Infection) Subject has appearance of upper or lower respiratory tract infection symptoms that are likely related to RSV Subject has a positive RSV diagnostic test Others as defined in the protocol Exclusion Criteria: Subject has history of wheezing Subject is known to have significant comorbidities Subject is known to be immunocompromised Subject is suspected of having a clinically relevant infection other than RSV Others as defined in the protocol

Ages Eligible for Study
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Minimum Age: 28 Days
Maximum Age: 23 Months

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: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: ALX-0171<br>Inhalation of ALX-0171 during 3 consecutive days | Biological: ALX-0171<br> <br> |
| Placebo Comparator: Placebo<br>Inhalation of Placebo during 3 consecutive days | Other: Placebo<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Safety and Tolerability as measured by the incidence of treatment emergent adverse events, clinical laboratory parameters and physical examination |  | 1 day before first dose to 14 days after first dose | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical activity as measured by the evaluation of the clinical response of the subjects |  | 1 day before first dose to 14 days after first dose | 
| Exploratory Pharmacokinetics as measured by the concentration of ALX-0171 in serum |  | Day 3 | 
| Exploratory Pharmacodynamics as measured by the concentration of viral load in respiratory secretions and exploratory biomarkers in serum |  | 1 day before first dose to 14 days after first dose | 
| Immunogenicity as measured by the concentration of anti-drug antibodies in serum |  | 1 day before first dose to 14 days after first dose |