Maintenance of remission following successful treatment of papulopustular rosacea with ivermectin 1% cream vs. metronidazole 0.75% cream: 36-week extension of the ATTRACT randomized study

Background There are a limited number of approved treatments for papulopustular rosacea (PPR) and remission is difficult to maintain after successful treatment. Objectives To investigate remission over a 36-week extension period in patients with moderate to severe PPR successfully treated with 16 weeks' treatment with ivermectin 1% cream once daily (QD) or metronidazole 0.75% cream twice daily (BID) in a randomized, parallel-group Phase III study. Methods Treatment was discontinued in patients initially successfully treated [Investigator's Global Assessment (IGA) score of 0 or 1] with ivermectin 1% cream QD (n = 399) or metronidazole 0.75% cream BID (n = 365; Part A) and patients were followed every 4 weeks for up to 36 weeks (Part B). Treatment with the same study treatment as used in Part A was only re-initiated if patients relapsed (IGA 2). Efficacy assessments were: time to first relapse; relapse rate; and number of days free of treatment. Safety assessments included incidence of adverse events and local cutaneous signs and symptoms. Results The median time to first relapse was significantly longer (115 days vs. 85 days) and relapse rates at the end of the study period significantly lower (62.7% vs. 68.4%) for patients initially successfully treated with ivermectin 1% compared with metronidazole 0.75%; Kaplan-Meier plot demonstrated a statistically significant difference between the two arms (P = 0.0365). The median number of days free of treatment was higher for ivermectin compared with metronidazole (196 days vs. 169.5 days; P = 0.026). The percentage of patients who experienced a related adverse event was equally low in both groups. Conclusion The results of this relapse study showed that an initial successful treatment with ivermectin 1% cream QD significantly extended remission of rosacea compared with initial treatment with metronidazole 0.75% cream BID following treatment cessation.