Squarex Pharma announced positive results from a phase 2 study of SQX770, a topical formulation of the immunomodulator squaric acid dibutyl ester (SADBE), in patients with recurrent herpes labialis. Data showed SQX770 was able to extend the time between herpes labialis outbreaks and reduced both the frequency and severity of outbreaks.
The multi-center, placebo-controlled, double-blinded randomized trial enrolled 139 subjects who reported four or more herpes labialis episodes in the past 12 months. Groups of patients received 1 or 2 doses of SQX770 or placebo. The study was designed to determine if the topical application of SADBE can delay outbreaks of HSV-1.
Results from the Phase 2 study demonstrated that a single topical dose of SQX770 applied to the upper arm significantly extended time to next herpes labialis outbreak and reduced both the frequency and severity of outbreaks. The greatest effect was recorded during days 43 to 121 following the drug’s application, suggesting SQX770 immunotherapy can take up to 6 weeks to fully exert a clinically meaningful effect on the immune system.
During the span between days 43 and 121, both the 1-dose group, as well as the pooled treatment groups demonstrated significantly superior statistic results compared to the placebo group for the following endpoints: average number of outbreaks, time to next outbreak, proportion of subjects with an outbreak, and proportion of subjects with moderate or severe outbreaks. No serious adverse events (SAEs) were reported.
An End-of-Phase 2 meeting is planned with the FDA for later this year, expected to be followed by a phase 3 clinical trial.
About Herpes Labialis
Herpes labialis is a common condition characterized by blisters or erosions on the lips and skin around the mouth and nose. Most cases are caused by herpes simplex virus type 1 (HSV-1), but 10-15% of cases are caused by HSV-2 with this percentage reportedly increasing. The natural history of HSV-1 infection leading to herpes labialis is that the virus typically initially infects oral mucosa, and then migrates to sensory neurons and establishes latency, typically in the trigeminal ganglion. The virus is later activated from latency by various events including fever, stress, cold or flu infection, immunosuppression, and sunlight. Upon activation, the virus migrates down sensory neurons to epithelial cells, typically on the vermillion border of the lip, and causes cell lysis and outbreaks as epidermal lesions. Outbreaks typically last 1-2 weeks. The frequency and severity of outbreaks is thought to be dependent on the effectiveness of immune control of the virus.
SQX770 is a topical formulation of the immunomodulator squaric acid dibutyl ester (SADBE).