Safety and Immunogenicity Study of BCG, H4:IC31, and H56:IC31 Revaccination in Healthy Adolescents

The aims of the phase 1b trial described here are to facilitate identification of assays and immune responses that could then be evaluated as correlates of risk and correlates of protection in efficacy studies and ultimately to provide leads for biomarkers of protection against tuberculosis. This study will complement one ongoing study (NCT02075203) evaluating the prevention of M. Tuberculosis infection using H4:IC31 (also known as AERAS-404).

This study proposes to further evaluate the safety and immunogenicity of H4:IC31, H56:IC31, and BCG revaccination. The study will be conducted in previously BCG vaccinated healthy adolescents, and will entail a thorough immunogenicity evaluation of these regimens incorporating unbiased systems vaccinology approaches and novel assessments of baseline and elicited responses that may impact vaccine responses. A major goal for this study is to generate immunological data on a wide range of immune responses using a variety of approaches including validated assessments, unbiased strategies, and novel exploratory assays to increase the likelihood of detecting responses correlating with risk or protection in the prevention of infection study. Investigators contributing to the proposed study have participated in a correlates analysis for an HIV vaccine exhibiting modest efficacy in which 2 correlates of risk were identified.

An additional aim of this study is to explore factors affecting vaccine induced responses that may also impact efficacy. For example, it is hypothesized that exposure to environmental mycobacteria may alter protection provided by BCG vaccination. Reagents for evaluating levels of exposure to environmental mycobacteria are in development as part of a concurrent collaborative study. An exploratory objective for this trial is to apply these reagents to examine whether such exposures influence immune responses elicited by the study vaccine and regimens.