A Clinical Trial to Evaluate the Safety and Immunogenicity of BG505 MD39.3, BG505 MD39.3 gp151, and BG505 MD39.3 gp151 CD4KO HIV Trimer mRNA Vaccines in Healthy, HIV-uninfected Adult Participants

This is an open-label, multicenter, randomized phase 1 study to evaluate the safety and immunogenicity of BG505 MD39.3, BG505 MD39.3 gp151, and BG505 MD39.3 gp151 CD4KO HIV trimer mRNA. These trimers are based on the BG505 MD39 native-like trimer reported in Steichen et al. Immunity 2016. The primary hypothesis is that the BG505 MD39.3 soluble and membrane-bound trimer mRNA vaccines will be safe and well-tolerated among HIV-uninfected individuals and will elicit autologous neutralizing antibodies.

Participants will receive BG505 MD39.3 mRNA, BG505 MD39.3 gp151 mRNA or BG505 MD39.3 gp151 CD4KO mRNA, at doses of 100 mcg or 250mcg, administered via intramuscular (IM) injections into the deltoid muscle. Participants will be evaluated for safety and immune responses through blood and lymph node fine-needle aspiration collection at specified timepoints throughout the study. A dose escalation plan will be implemented, whereby sentinel safety groups for each of the three low-dose groups in Part A would be enrolled and evaluated for safety 2 weeks after the first vaccination. If safety criteria are met, then enrollment of the Part B sentinel safety groups and the remainder of the Part A participants would commence. Safety for the sentinel groups in Part B will be assessed after the first vaccination prior to full enrollment of Part B. In addition, standard safety evaluations will occur routinely throughout the trial.