Development of a HIV-1 vaccine using an orally-administered, replication-competent adenovirus serotype 4 vector expressing Env clade C glycoprotein

Background Our hypothesis is that the replicating Ad4 vector approach, may be the best strategy for an effective HIV-1 vaccine due to advantages of demonstrated clinical safety and immunogenicity of both the Ad4 backbone and an Ad4 H5N1 vector influenza vaccineevaluated in Phase 1. Unlike other vectors, it can be bioengineered to express full-length HIV-1 Env gp160. More than 50% of global HIV-1 infections are caused by cladeC viruses and therefore we initiated development of Ad4-Env160 vaccine using an Env cladeC sequence obtained from CHAVI.