HerpV

What it is

HerpV, formerly called AG-707, is made of 32 synthetic 35mer HSV-2 peptides non-covalently complexed with recombinant human Hsc70 protein. The peptides are derived from 22 HSV-2 proteins, and the vaccine is formulated with the saponin adjuvant QS-21. It is described as a therapeutic vaccine candidate, meaning it is intended for people who already have HSV-2, and a 2024 review calls it a subunit vaccine from Agenus.

Where it stands

In a Phase I study, thirty-five HSV-2-infected participants were randomized to HerpV plus QS-21, HerpV alone, QS-21 alone, or vehicle; the sources do not give a registry number for that study. The study paper reports that the vaccine was well tolerated and safe. All seven participants with evaluable samples who received HerpV with QS-21 showed a statistically significant CD4+ T cell response to HSV-2 antigens, and most also showed a significant CD8+ T cell response. Agenus Inc. then sponsored NCT01687595, a Phase 2a, double-blinded, randomized trial of HerpV with QS-21 versus placebo on viral shedding in adults with recurrent genital herpes. That trial enrolled 80 participants (actual count), was completed in 2015, and has results posted on the registry, though those results are not in the sources reviewed here. A ClinicalTrials.gov search on 2026-09-27 for records naming HerpV returned 1 record, and none had an ongoing status. A 2024 review states that HerpV has not advanced further.

What this does and doesn’t mean

In mice, HerpV produced CD4+ and CD8+ T cell responses in three strains and gave significant protection from viral challenge in a prophylaxis model. In a guinea pig therapeutic model of existing infection, the paper reports that it showed signals of activity. These animal results are not human results, and the mouse prophylaxis finding does not speak to the therapeutic use the human trials tested. The T cell responses seen in the Phase I study are immune measurements, not evidence that the vaccine reduced shedding or outbreaks. The sources here do not report the Phase 2a trial’s outcomes, so they do not show whether HerpV reduced viral shedding.