Two randomized phase III clinical trials evaluating anti-inflammatory dose doxycycline (40-mg doxycycline, USP capsules) administered once daily for treatment of rosacea

Abstract

Background: Doxycycline monotherapy at antimicrobial doses has been shown to be effective for the treatment of rosacea.

Objective: To evaluate the efficacy and safety of once-daily anti-inflammatory dose doxycycline for the treatment of rosacea.

Methods: In two phase III, parallel-group, multicenter, randomized, double-blind, placebo-controlled studies (studies 301 and 302), patients received 40-mg of controlled-release doxycycline (n = 269) or placebo (n = 268) for 16 weeks. The primary efficacy end point was the mean change from baseline in facial inflammatory lesion count.

Results: The mean lesion count at baseline was approximately 20 in each study arm. At week 16, the mean change from baseline in lesion count in the active-treatment groups was -11.8 in study 301 and -9.5 in study 302 compared with -5.9 and -4.3, respectively, in the placebo groups (P < .001 for both comparisons). Anti-inflammatory dose doxycycline was well tolerated; the most common adverse events were nasopharyngitis (4.8%), diarrhea (4.4%), and headache (4.4%).

Limitations: In both studies, the reduction of inflammatory lesion counts did not plateau within the 16-week time frame in either treatment group. Rosacea is often treated for a period of months or years. The duration of the studies did not allow for assessment of safety beyond 16 weeks or whether the progressive improvement seen with active treatment would continue beyond 16 weeks. Neither study assessed the effect of treatment in patients with only erythematotelangiectatic (subtype 1) rosacea.

Conclusion: Once-daily anti-inflammatory dose doxycycline appears to be effective and safe for the treatment of rosacea.