CI

At a glance

ClinicalIndex Comparison Record
Phase 1Completed· 60 enrolled
Drug / intervention
Influenza RG-A/Texas/71/2017 (H3N2) Challenge +1 morebiological
Likely dose
Influenza RG-A/Texas/71/2017 (H3N2) Challenge 0.5 mLfrom record
Structured eligibility isn't available for this trial yet — see the full criteria in the Eligibility tab below.

Standardized by ClinicalIndex from the ClinicalTrials.gov record · verify against the source.

Search/NCT04978454
NCT04978454Phase 1Completed

A Multicenter, Blinded, Randomized, Placebo-Controlled, Dose-Ranging Influenza Challenge Study in Healthy Adult Volunteers to Determine the Optimal Infection Dose and Safety of a Recombinant H3N2 (A/Texas/71/2017 (H3N2), Clade 3C3a) Influenza Challenge Virus

National Institute of Allergy and Infectious Diseases (NIAID)·interventional·Posted Jul 27, 2021·Updated Aug 28, 2025

In Brief

A Phase 1 clinical trial evaluating Influenza RG-A/Texas/71/2017 (H3N2) Challenge and Placebo for Influenza. Completed, enrolled 60 participants across 2 sites.

Detailed Summary

An open-label, dose-ranging influenza challenge study in healthy adult volunteers to determine the optimal infection dose and safety of a recombinant H3N2 (A/Texas/ A/Texas/71/2017 (H3N2, clade 3C3a) influenza strain. The goal of this study is to find a challenge virus dose that is safe and can achieve a symptomatic influenza Attack Rate (AR) that will be sufficiently high for utilization in future vaccine or intervention studies. The optimal dose of the three considered is broadly defined as the minimum challenge virus dose that elicits the highest AR without meeting safety-stopping criteria. Additionally, viral recovery, clinical symptoms, and immune responses over the post-challenge period will be described by challenge dose group. This study will last for up to 1 year depending upon the number of challenge cohorts enrolled given the adaptive dose-escalation design. The populations are healthy males and non-pregnant, non-breastfeeding females aged = 18 and \< 46 years of age with a serum HAI antibody titer of \</=1:40 against influenza A/Texas/71/2017 (H3N2), clade 3C3a. The study will enroll and challenge up to 106 (plus 8 shams) healthy adult volunteers with the H3N2 (A/Texas/71/2017 (H3N2), clade 3C3a) influenza virus challenge strain. The primary objectives are: 1) To determine the optimal infectious dose of a recombinant influenza virus (A/Texas/71/2017 (H3N2), clade 3C3a) to be used as a clinical challenge strain in future vaccine efficacy or intervention studies as assessed by viral shedding and clinical symptoms. 2) To describe viral detection by quantitative and qualitative Reverse Transcription - Polymerase Chain Reaction (RT-PCR) from study subjects at baseline and post-challenge. 3) To document clinical symptoms from self-reported surveys and standardized symptom scales at baseline and post-challenge.

Study Details

Study Typeinterventional
Allocation--
Masking--
Primary Purpose--
ConditionsInfluenza
CountriesUnited States
Collaborators--

Timeline

Phase 1CompletedFinished
20222023202420252026
First PostedJul 27, 2021
Enrollment StartAug 19, 2021
Primary CompletionSep 22, 2022
TodayJul 2, 2026
Enrollment to primary: 1.1 yearsPosted 4.9 years ago

Interventions

Influenza RG-A/Texas/71/2017 (H3N2) Challengebiological

RG-A/Texas/71/2017 (H3N2) is an infectious influenza virus and requires handling at BioSafety Level 2. The challenge virus will be administered intranasally in a volume of approximately 0.5 mL per nostril. Intranasal challenge will be carried out using the Intranasal Mucosal Atomization ( MAD Nasa(TM)) Device attached to a 1 mL syringe.

Placeboother

Sucrose phosphate glutamate (SPG) inoculum