Penciclovir cream for the treatment of sunlight-induced herpes simplex labialis: a randomized, double-blind, placebo-controlled trial. Penciclovir Cream Herpes Labialis Study Group.

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 < or = 0.040), itching (P < or = 0.032), burning (P < or = 0.028), and tenderness (P < or = 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 < or = 0.003), noticeability (P < or = 0.003), amount of scab/crust (P < or = 0.003), raised/ swollen area (P < or = 0.040), soreness/tenderness (P < or = 0.043), and overall severity (P < or = 0.001) throughout the study period.

Conclusions: Penciclovir cream has demonstrated efficacy for a broad 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.