Placebo-controlled Phase 1/2
Our first placebo-controlled Phase 1/2 clinical trial, conducted at Massachusetts General Hospital, found that a single topical dose of our SX770 formulation tripled median time to next outbreak from 40 days in the placebo group to >124 days in the treatment group (p<0.01).
Mechanism of Action Clinical Trial
Our second clinical trial studied the immune gene expression of persons infected with HSV-1 who had frequent cold sores (≥6 episodes per year) versus those with few episodes, and found many differences in immune gene expression between the groups, including significantly greater interferon gamma expression in persons with few or no outbreaks.
We then dosed the persons who had frequent outbreaks once on the arm with SQX770. This caused their immune gene signature to be more like the persons with few or no outbreaks in every respect, including significantly greater interferon-gamma expression.
Phase 2 Clinical Trial
We have conducted a larger placebo-controlled clinical trial at Massachusetts General Hospital, Stanford University, and other sites in approximately 140 persons with 4 or more herpes labialis outbreaks per year. The results have published in the Journal of the American Academy of Dermatology. As expected and shown in the mechanism of action clinical trial, it took about 6 weeks for the drug to exert its effect of changing the immune response to the HSV-1 virus and to begin preventing outbreaks. Over days 43-121 after one dose on day 1, the treated group had a 2.42-fold delay in time to next outbreak, 2.64-fold fewer outbreaks, and 3.5-fold fewer moderate-to-severe outbreaks. All of those differences were statistically significant. Patients were followed for a full year, and it was found that after day 121 or about 4 months the effect of the single dose waned and differences with the placebo group were smaller. But even so, over days 1-365 the treated group had 2.09-fold fewer moderate-to-severe outbreaks than the placebo group, and that difference was statistically significant.
Since the effect of a single dose partially waned after 3-4 months, we will dose every 3 months for 1 year in our Phase 3 trials and plan to sell the commercial product with the prescribing information that it should be dosed once every 3 months to prevent cold sore outbreaks.