Intervention: Squaric acid dibutyl ester
Trial phase: Phase 2
SMILES: CCCCOc1c(OCCCC)c(=O)c1=O
Sex: All
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 10
Group description: Treated with 2% Squaric Acid Dibutyl Ester (SADBE) on day 0 and with 0.5% SADBE on the visits at week 3, week 6, week 9, and month 8.

Squaric Acid Dibutyl Ester: 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).
Eligibility criteria:
Inclusion Criteria:

Age ≥ 18 and ≤ 65
Clinical diagnosis of herpes labialis, which may be made at the screening visit based on the patient's self-reported history of symptoms. An active herpes labialis outbreak at the time of entry into the clinical trial will neither be required nor will be an exclusion criterion.

Self report having four (4) or more episodes of herpes labialis in the past 12 months.

Subjects will NOT be told that four-or-more episodes in the previous 12 months is the entry criterion. Subjects will be asked "How many separate episodes of cold sores have you had in the previous 12 months?" They will be included if they give an answer of four or more and excluded if they give an answer of three or fewer.

At least half of the subject's episodes of the previous 12 months should be vesicular in nature and at least half preceded by prodromal symptoms. Prodromal symptoms may include tingling, itching, burning or pain before the development of a herpetic lesion.

Exclusion Criteria:

Pregnant or lactating females.
Current or recurrent non-herpetic infection or any underlying condition that may predispose to infection or anyone who has been admitted to the hospital due to bacteremia, pneumonia or any other serious infection in the last 12 months.
Therapy with glucocorticoid or immunosuppressants at time of recruitment or within past 4 weeks prior to the screening visit, or at any time during the study (including inhaled corticosteroids for asthma), except for topical steroids in sites other than face.
History of malignancy (except patients with surgically cured basal cell or squamous cell skin cancers).
History of organ transplantation.
HIV-positive status determined by history at screening or known history of any other immunosuppressive disease.
Severe co-morbidities (CHF [NYHA class II or worse], MI, CVA or TIA) within 3 months of screening visit, current unstable angina pectoris or oxygen-dependent severe pulmonary disease.
Known hypersensitivity to Dimethyl sulfoxide (DMSO).
Any condition judged by the investigator to cause this clinical trial to be detrimental to the patient.
Subject is currently enrolled in another investigational device or drug trial(s), or subject has received other investigational agent(s) within 28 days of the screening visit.
Previous exposure to SADBE (squaric acid or squaric acid dibutyl ester).
Subject has an abnormal skin condition (e.g., acne, eczema, rosacea, psoriasis, albinism, or chronic vesiculo-bullous disorder) that occurs in the area ordinarily affected by herpes labialis
Subject has an abnormal skin condition (e.g., eczema, rosacea, psoriasis, albinism, or chronic vesiculo-bullous disorder) that occurs in the inner aspect of either upper arm (the area where drug will be applied).
Subject has had a vaccine for either HSV-1 or HSV-2.
Subject has had treatment with anti-viral therapy (including ABREVA) within 2 weeks before first dose of SADBE or at any time during the study.