Clinical and experimental assessment of the effects of a new topical treatment with praziquantel in the management of rosacea

Background: Rosacea is a common, chronic, and inflammatory skin disease. The burden imposed by this condition requires that new topical treatments be sought to enlarge the arsenal of drugs available in order to better manage this disease.

Objectives: This study was conducted to carry out an in vitro/in vivo evaluation of the antimicrobial activity of 3% praziquantel (PZQ) ointment and to determine its efficacy and safety in the treatment of rosacea.

Methods: Patients with rosacea (n = 65) participated in a 16-week, randomized, single-blind pilot study of the effects of twice-daily monotherapy with 3% PZQ ointment vs. placebo (vehicle ointment). Efficacy was assessed clinically using the Investigator's Global Assessment Scale (IGAS) and the Clinical Erythema Assessment Scale (CEAS). Patients' quality of life was also determined using the Dermatology Life Quality Index (DLQI). The antimicrobial potential of 3% PZQ ointment was assessed by agar diffusion assay.

Results: Scores on the IGAS and CEAS showed PZQ ointment to have a statistically significant therapeutic advantage over the placebo treatment (P < 0.001). At week 16, the PZQ group demonstrated a statistically significant greater reduction in CEAS score than the placebo group (P < 0.001). Analysis of CEAS scores showed that 41.9% of patients in the PZQ group and 18.2% of those in the placebo group achieved a CEAS score equivalent to a rating of "none". Mean scores on the DLQI at baseline and at the end of the study were, respectively, 15.8 and 4.1 in the praziquantel group. The PZQ-treated group also experienced a statistically significant improvement in comparison with the placebo group at week 16 (P < 0.001). The inhibitory zone indicating the extent of antimicrobial activity of 3% PZQ ointment ranged from 6 mm to 17 mm. No serious treatment-related adverse events occurred in either treatment group.

Conclusions: Use of 3% PZQ ointment twice daily for 12 weeks resulted in significantly better effects than a placebo treatment in improving rosacea and the patient's quality of life.