Squarex

Primary Objective: To assess local and generalized adverse events with repeat topical application of 2% and 0.5% squaric acid dibutyl ester (SADBE) in subjects with frequent herpes labialis (4 or more episodes in the previous 12 months).
Secondary Objective: To assess efficacy of repeat topical application of 2% and 0.5% SADBE in the prevention of herpes labialis episodes.

Subjects were recruited who were positive for antibody against herpes simplex virus type 1 (HSV-1) and self-reported having in the previous 12 months
6 or more herpes labialis outbreaks (group A),
1 or 2 outbreaks (group B), or
zero outbreaks (group C). Twelve subjects in each group were recruited. Blood was collected from these persons and peripheral blood mononuclear cells (PBMCs) isolated and tested for proliferation in vitro when stimulated with HSV-1-infected cell extracts, free HSV-1 virus, or Candida albicans extract. Candida albicans is a ubiquitous infectious fungus and its extract is used as a test of general immune response. RNA was also isolated from the PBMCs after incubation in the three stimuli and expression of 41 immune-related genes quantified by quantitative real-time PCR. Also serum anti-HSV-1 IgG levels were quantified.
After the blood collection on day 1, the persons in group A (frequent cold sore sufferers) were treated with a single topical application of 2% squaric acid dibutyl ester (SADBE) in DMSO, applied to the inner aspect of the upper arm. These subjects returned on days 15 and 57 for blood collection, and their PBMCs were tested again on those dates for proliferation in vitro against the same stimuli and for gene expression and for serum anti-HSV-1 IgG levels.

This study evaluates the safety and efficacy of SADBE in the prevention of recurrent herpes labialis in adults. Two-thirds of the participants will receive a SADBE solution, while the other third will receive only the vehicle as a placebo control. The solutions will be administered topically to the patient's arms. The study will compare a single-arm application versus a two-arm application versus two placebo doses on the arm.