Evaluation of ALX-0171 in Japanese Children Hospitalized for Respiratory Syncytial Virus Lower Respiratory Tract Infection

Phase 2

Terminated

Brief Summary: This was a randomized, double-blind, multicenter, Phase II study (NCT03418571) designed to support the selection of an optimal dose of inhaled ALX-0171 for further clinical development, taking ethnicity into consideration.

Based on the results of the Phase IIb dose-ranging study ALX0171-C201 (RESPIRE), the Sponsor decided to discontinue ALX-0171 development in infants and to early terminate the ALX0171-C203 study.

Detailed Description: Four dose levels were planned to be evaluated in four consecutive cohorts consisting of Japanese infants and young children aged 28 days to \<2 years with a gestational age ≥33 weeks who were hospitalized for and diagnosed with respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI):

* Dose level 1: target dose of 1.5 mg/kg

* Dose level 2: target dose of 3.0 mg/kg

* Dose level 3: target dose of 6.0 mg/kg

* Dose level 4: target dose of 9.0 mg/kg

Each cohort was planned to consist of 15 subjects enrolled and randomly assigned to receive ALX-0171 or placebo, in an allocation ratio of 4:1 (N = 12 active versus N = 3 placebo per cohort).

Due to early termination of the trial, only enrollment of Cohort 1 could be completed as planned. For Cohort 2, only 1 subject was screened but did not meet the eligibility criteria and was considered a screen failure. Therefore, data were not available for treatment groups ALX-0171 3.0 mg/kg, 6.0 mg/kg, and 9.0 mg/kg.

Of note, in line with applicable guidelines, an Independent Data Monitoring Committee (IDMC) was assigned to monitor the study. Upon completing of Cohort 1, the IDMC reviewed the available unblinded safety data and unanimously recommended to continue the study with no changes to the protocol.

Recruitment & Eligibility

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Arm && Interventions

Group	Intervention	Description
Placebo	Placebo	-
ALX-0171 1.5 mg/kg	ALX-0171 1.5 mg/kg	-

Primary Outcome Measures

Name	Time	Method
Safety and Tolerability of Inhaled ALX-0171 1.5 mg/kg as Measured by the Number of Serious and Non-serious TEAEs.	From the subject's first study drug administration until completion of the subject's last visit, an average of 4 weeks	Number of serious and non-serious TEAEs reported in the ALX-0171 1.5 mg/kg treatment group and placebo treatment group.
Safety and Tolerability of Inhaled ALX-0171 1.5 mg/kg as Measured by the Number of Subjects With at Least 1 Serious or Non-Serious Treatment-emergent Adverse Event (TEAE).	From the subject's first study drug administration until completion of the subject's last visit, an average of 4 weeks	Number of subjects reported with at least 1 serious or non-serious TEAEs in the ALX-0171 1.5 mg/kg treatment group and placebo treatment group.

Secondary Outcome Measures

Name	Time	Method

Locations (4): Investigator Site
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Ōmura, Japan
Investigator site 1
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Yokosuka, Japan
Investigator site 2
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Yokosuka, Japan
Investigator site
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Wako, Japan