Once-daily topical brimonidine tartrate gel 0·5% is a novel treatment for moderate to severe facial erythema of rosacea: results of two multicentre, randomized and vehicle-controlled studies

Rosacea is a common and chronic disorder, characterized by flushing and persistent erythema in the central facial area.1,2 The disease onset is typically between the ages of 20 and 50 years, and women are more often affected than men.3,4 Rosacea has considerable psychosocial impact and causes embarrassment, anxiety and low self-esteem.5,6 Erythema is the primary feature of rosacea and presents ubiquitously among patients. Other cutaneous signs such as telangiectasia, papules, pustules and oedema may also present.7,8 Although several medications are approved for the treatment of inflammatory lesions of rosacea, there is currently no approved medication directly targeting erythema of rosacea, making it a key unmet medical need.4 In the absence of effective treatment, patients are usually advised to avoid environmental and lifestyle triggers that can exacerbate erythema.9–11 While the exact cause of erythema of rosacea is not known, it is hypothesized that erythema results from dysregulation in the cutaneous vasomotor responses, which leads to abnormal dilation of facial blood vessels upon various stimuli.12–14 Therefore, agents with vasoconstrictive activity may have a symptomatic effect on erythema. Transcriptomic studies suggest the involvement of adrenergic receptors in the neurovascular regulation pathway.15 Brimonidine tartrate (BT) is a highly selective α2-adrenergic receptor agonist, with potent vasoconstrictive activity.16 It is currently approved for the treatment of open-angle glaucoma, with well-documented efficacy and safety.17,18 BT applied topically to the face is hypothesized to reduce erythema of rosacea. In the present two Phase II studies, we aimed to determine the optimal dose regimen of BT in the treatment of moderate to severe erythema of rosacea, and to evaluate the efficacy and safety of the treatment using two specifically developed novel scales for erythema.