Monday, May 6, 2024
5/6/2024
Overall Summary A protective vaccine for HIV is arguably the most important prevention strategy to end the global HIV pandemic. The RV144 trial demonstrated a correlation between protection and envelope (Env) specific serum IgG antibodies. However, there was a notable lack of HIV-specific neutralizing antibodies (nAbs) and T cell responses. The DNA platform has several advantages, it is (1) simple to design, (2) can co-deliver molecular adjuvants, (3) can deliver complex structural antigens, and (4) is safe and well tolerated, even after numerous boosts. In our previous IPCAVD program we developed DNA-launched nanoparticle (DLNP) vaccines targeting Env which induced potent and neutralizing immunity in vivo. We have also developed DNA-launched native-like trimer (DL-NLT) immunogens including the clinically relevant BG505 MD39 trimer (Xu et al. Nat. Comm 2022). Protein nanoparticles are difficult to manufacture and poorly stimulate CD8+ T cells. We reported that in vivo assembled nanoparticles drive extremely rapid and strong B and T cell immunity. Functional antibody responses require help from germinal center (GC) follicular helper T cells (TFH). In previous clinical trials with HIV antigens, we observed increased B and T cell responses in the presence of plasmid-encoded IL-12 (pIL-12). Work from members of this team has demonstrated that co-delivery of adenosine deaminase (ADA-1) and plasmid-encoded IL-21 (pIL-21) can enhance antibody induction in mice in a GC-dependent fashion. Here, we combine the DLNP and DL-NLT platforms to generate DNLPs bearing stabilized NLTs focusing immune responses on apex and CD4bs B cell lineage-targeting Envs (DNLP-ACE). We will characterize humoral and cellular immunity to these constructs in the presence of molecular IL-12 with and without additional GC-targeting adjuvants, in mouse and non-human primate vaccination studies. The overarching hypothesis of this project is that DLNP-ACE immunogen technology combined with the co-delivery of genetic adjuvants is a novel approach for the development of HIV-1 vaccines that promotes robust, durable, broad, and neutralizing antibody responses, and supports effector T cell function in vivo A key innovation of this project will be to integrate the selected DNLP-ACE HIV vaccine constructs in a dual expressing plasmid construct with next generation noninvasive intradermal skin electroporation (EP) devices which promote functional CTL and humoral immune responses. The clinical development plan for this IPCAVD is directed by a leading HIV vaccine development organization, Inovio Pharmaceuticals (INO), which has expertise in development of synthetic DNA vaccines and in vivo electroporation delivery. Inovio will oversee clinical grade production of 2 plasmid constructs at a state- of-the-art cGMP plasmid manufacturing facility. Inovio’s processes have passed rigorous international regulatory reviews and have been used in dozens of human clinical trials in the U.S., Europe and Asia, including multiple Phase II and in Phase III studies.
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