Summary and objectives
The purpose of this study is to define the safety and immunogenicity of IHV01 and A244/AHFG with and without ALFQ at a full dose and at a fractional dose (one-fifth of a full dose) in a late boost setting for participants who had previously received a late boost of AIDSVAX®B/E with or without ALVAC in RV306. Safety will be assessed through the frequency of the overall and specific post-vaccination reactions. Blood, lymph nodes, sigmoid tissue, and mucosal specimens/secretions will be collected to assess humoral, cell-mediated, innate, and mucosal immune responses. Healthy, HIV-uninfected participants, at a low risk for HIV infection, available for 12 months, who were randomized to receive active vaccine in RV306 and completed all vaccinations will be enrolled. A total of 120 participants will be enrolled across four vaccination groups. In each group, 25 participants will receive IHV01 and A244/ AHFG at a full or fractional dose with or without ALFQ and 5 participants will receive placebo. All injections, whether vaccine or placebo, will be a one-time intramuscular (IM) administration into the quadriceps muscle at study Day 0. Participants will be followed-up for up to 48 weeks after enrollment on days 1, 7, 14, 168 and 336. Mucosal secretion collections and endocervical cytobrush/swab procedures will be performed at Weeks 0, 2, 24, and 48 on consenting participants. Leukapheresis, sigmoid biopsy, and lymph node biopsy
procedures will be performed only at Week 2 on consenting participants.