Safety and immunogenicity of investigational herpes simplex virus-2 vaccines in adults with recurrent genital infection

HSV529 and G103 are investigational therapeutic vaccines for genital herpes. HSV529 is a replication-defective HSV-2. G103 contains three recombinant HSV-2 proteins: truncated UL19 and gD2 and full-length UL25. A randomized, placebo-controlled clinical trial was conducted over a two-dose schedule to assess various combinations of G103 and HSV529 with GLA-SE adjuvant in 24 participants. No immediate unsolicited adverse reactions were observed. Most injection site reactions (>50 %) were grade 2 with one reported grade 3 swelling. Grade 2 systemic reactions (headache and myalgia) were independent of GLA-SE dose. The vaccine candidates showed adequate safety profiles. All participants had baseline immune responses to HSV-2. gD2, UL19, and UL25-specific CD4 T cells increased in G103 recipients after the first dose and were most robust for gD2. Binding antibody levels increased most markedly for UL25, as did neutralizing antibodies.