Regulatory Decision Summary for Sitavig

Health Canada considers that the benefit/risk profile of Sitavig is favourable when used as directed for the treatment of recurrent herpes labialis (cold sores) in immunocompetent adults.

The indication was based on the results of one Phase 3 trial (study BA2005/21/02 or LIP trial) in patients with a history (defined as at least 4 episodes in the preceding 12 months) of herpes labialis (cold sores). The patients were to be randomized to initiate Sitavig or a placebo at the onset of symptoms. To be included in the trial, patients were required to have prodromal symptoms in at least 50% of their prior episodes. A total of 1721 patients were randomized 1:1 to receive a single dose of Sitavig or placebo. Of the 1721 randomized, 775 initiated treatment (378 in the Sitavig group and 397 in the placebo group), of which 521 developed a primary vesicular lesion.

In the analysis supporting approval, the median duration of exposure using Hodges-Lehmann estimates was 5.49 days for Sitavig and 6.00 days for placebo, with a median difference of 0.58 days (p-value 0.0289). The labelling in the Product Monograph noted that the mean and median durations of the recurrent herpes labialis episode (ITT population, n = 771) were at least half a day shorter in patients treated with Sitavig compared to patients treated with placebo.

No deaths were reported. The product was well tolerated, and there were no significant safety issues. Headache was the most common adverse drug reaction, along with application site pain.

Based on the clinical data submitted, Health Canada considers that the anticipated benefits of Sitavig outweigh the potential risks under the conditions of use described in the Sitavig Product Monograph at this time.