Rosacea: An Update on Medical Therapies
Rosacea: An Update on Medical Therapies
Several topical acaricidal agents (permethrin 5%, crotamiton 10%, and ivermectin 1%) have been studied for the treatment of rosacea, all of which primarily target Demodex folliculorum and Demodex brevis mites. The potential etiological role of these mites in rosacea has been debated for many years. There is renewed interest in Demodex mites due to recent studies that demonstrated antigenic proteins produced by a Demodexisolated bacterium (Bacillus oleronius) may aggravate the inflammatory responses in papulopustular and ocular rosacea, as well as in erythematotelangiectatic rosacea. This pathogenic scenario implicating the bacterium rather than the Demodex mites themselves may explain the efficacy of antibacterial therapies in rosacea.
Numerous case reports have been published on the successful treatment of rosacea with topical acaricidal agents refractory to other therapies, however, data from controlled, randomized trials are lacking. Phase 3 randomized clinical trials studying the impact of topical ivermectin 1% cream in rosacea are underway, which compare its efficacy and safety with metronidazole 0.75% cream and azelaic acid 15% gel. Results are expected to be available in the near future.
Diffuse and persistent facial erythema has long been a clinical challenge in rosacea therapy. One contributing factor to diffuse facial erythema is abnormal cutaneous vasomotor responses, which leads to enlarged superficial facial blood vessels. Importantly, however, these blood vessels remain responsive to vasoactive stimuli, hence, the growing interest in alpha (α)-2 adrenergic receptor agonists as a therapeutic option to manage the nontransient erythema.
Brimonidine tartrate 0.33% gel, approved by the US FDA in August 2013 and by Health Canada in February 2014, is the latest addition to the treatment armamentarium and the first topical agent approved for the treatment of facial erythema of rosacea. Brimonidine (initially available in prescription eye drops for the treatment of glaucoma) is a highly selective α-2 adrenergic receptor agonist with potent vasoconstrictive activity.
In two Phase 3 randomized, double-blind pivotal trials, topical brimonidine tartrate (BT) gel 0.5% once-daily was found to be significantly more effective than vehicle over a 4 week treatment period. In the two trials, approximately 24.82% of the patients using BT gel 0.5% (vs. 9.76%; p<0.05) were assessed on day 29 to have at least a two-grade improvement by both clinicians and patients over 12 hours after drug application, with peak improvements observed at 3 and 6 hours. Noticeable improvement (one-grade based on Clinician's Erythema Assessment and Patient's Self-Assessment) was observed (28.2% vs. 5.9%; p<0.01) as early as 30 minutes after the first application on day 1. Adverse events were mildly elevated in the active treatment group, but events were mostly skin-related, transient, and mild, with the most commonly reported being worsening of erythema (5.1%), pruritus (5.0%), skin irritation (1.2%), and worsening of rosacea (1.1%). There was no evidence of tachyphylaxis, rebound, or aggravation of telangiectasia or inflammatory lesions. Additionally, recently published data from a 12-month, multicenter, open-label study reported sustained efficacy with no incidence of tachyphylaxis in the long-term treatment of moderate to severe erythema of rosacea.
Phase 2 clinical trial for another promising α-adrenergic receptor agonist, called oxymetazoline, has recently been completed. Results should be available in the near future.
New and Emerging Therapies
Topical Ivermectin
Several topical acaricidal agents (permethrin 5%, crotamiton 10%, and ivermectin 1%) have been studied for the treatment of rosacea, all of which primarily target Demodex folliculorum and Demodex brevis mites. The potential etiological role of these mites in rosacea has been debated for many years. There is renewed interest in Demodex mites due to recent studies that demonstrated antigenic proteins produced by a Demodexisolated bacterium (Bacillus oleronius) may aggravate the inflammatory responses in papulopustular and ocular rosacea, as well as in erythematotelangiectatic rosacea. This pathogenic scenario implicating the bacterium rather than the Demodex mites themselves may explain the efficacy of antibacterial therapies in rosacea.
Numerous case reports have been published on the successful treatment of rosacea with topical acaricidal agents refractory to other therapies, however, data from controlled, randomized trials are lacking. Phase 3 randomized clinical trials studying the impact of topical ivermectin 1% cream in rosacea are underway, which compare its efficacy and safety with metronidazole 0.75% cream and azelaic acid 15% gel. Results are expected to be available in the near future.
Topical Brimonidine and Oxymetazoline
Diffuse and persistent facial erythema has long been a clinical challenge in rosacea therapy. One contributing factor to diffuse facial erythema is abnormal cutaneous vasomotor responses, which leads to enlarged superficial facial blood vessels. Importantly, however, these blood vessels remain responsive to vasoactive stimuli, hence, the growing interest in alpha (α)-2 adrenergic receptor agonists as a therapeutic option to manage the nontransient erythema.
Brimonidine tartrate 0.33% gel, approved by the US FDA in August 2013 and by Health Canada in February 2014, is the latest addition to the treatment armamentarium and the first topical agent approved for the treatment of facial erythema of rosacea. Brimonidine (initially available in prescription eye drops for the treatment of glaucoma) is a highly selective α-2 adrenergic receptor agonist with potent vasoconstrictive activity.
In two Phase 3 randomized, double-blind pivotal trials, topical brimonidine tartrate (BT) gel 0.5% once-daily was found to be significantly more effective than vehicle over a 4 week treatment period. In the two trials, approximately 24.82% of the patients using BT gel 0.5% (vs. 9.76%; p<0.05) were assessed on day 29 to have at least a two-grade improvement by both clinicians and patients over 12 hours after drug application, with peak improvements observed at 3 and 6 hours. Noticeable improvement (one-grade based on Clinician's Erythema Assessment and Patient's Self-Assessment) was observed (28.2% vs. 5.9%; p<0.01) as early as 30 minutes after the first application on day 1. Adverse events were mildly elevated in the active treatment group, but events were mostly skin-related, transient, and mild, with the most commonly reported being worsening of erythema (5.1%), pruritus (5.0%), skin irritation (1.2%), and worsening of rosacea (1.1%). There was no evidence of tachyphylaxis, rebound, or aggravation of telangiectasia or inflammatory lesions. Additionally, recently published data from a 12-month, multicenter, open-label study reported sustained efficacy with no incidence of tachyphylaxis in the long-term treatment of moderate to severe erythema of rosacea.
Phase 2 clinical trial for another promising α-adrenergic receptor agonist, called oxymetazoline, has recently been completed. Results should be available in the near future.
Source...