Penciclovir cream for the treatment of sunlight-induced herpes simplex labialis: A randomized, double-blind, placebo-controlled trial

Objective: The purpose of this study was to further define the therapeutic value of penciclovir cream in the treatment of sunlight-induced herpes labialis by comparing its efficacy and tolerability with those of an inactive control (purified water). Methods: In this randomized, double-blind, placebo-controlled, parallel-group clinical trial, lesions were induced by exposure to sunlight. Treatment was self-initiated within 1 hour of development of the signs or symptoms of a recurrence. Results: Healthy male and female patients (mean age, 38.3 years; range, 18 to 81 years) who had a history of sunlight-induced herpes labialis (mean of 6 recurrences in previous 12 months) applied either penciclovir cream (n = 266) or purified water (n = 275). Penciclovir cream significantly decreased the time to lesion healing (P < 0.001), with a reduction in median time of up to 2 days. The efficacy of penciclovir cream was further supported by a significant reduction in maximum lesion area (P = 0.008), a faster loss of lesion-associated symptoms (P = 0.026), and significant reductions in daily assessments of pain (P less than or equal to 0.040), itching (P less than or equal to 0.032), burning (P less than or equal to 0.028), and tenderness (P less than or equal to 0.026) as moderate or severe. These effects were reinforced by the results of the daily self-assessment of lesion attributes, with significantly fewer severe/extreme assessments of lesion size (P less than or equal to 0.003), noticeability (P less than or equal to 0.003), amount of scab/crust (P less than or equal to 0.003), raised/ swollen area (P less than or equal to 0.040), soreness/tenderness (P less than or equal to 0.043), and overall severity (P less than or equal to 0.001) throughout the study period. Conclusions: Penciclovir cream has demonstrated efficacy for a bread range of clinically important outcomes. Significant effects on lesion area, lesion symptoms, and other lesion attributes extend the clinical efficacy of penciclovir cream beyond lesion healing.