Abstract
Purpose:
Vasoconstrictors are widely used to treat ocular redness but there is a need for identifying new topical formulations that are more effective with reduced side effects. Brimonidine is a highly selective α2-adrenergic receptor (AR) agonist, with minimal action at α1-ARs associated with tachyphylaxis and rebound congestion. We compared the safety and tolerability of low dose brimonidine tartrate ophthalmic solution 0.025%, with its vehicle in a population of pediatric, adult, and geriatric subjects.
Methods:
The study was a Phase 3 multi-center, double-masked, randomized, vehicle-controlled, parallel-group study in pediatric (5-17 yrs), adult (≥18-<65 yrs), and geriatric (≥65 yrs) healthy subjects, that comprised 4 study visits over ~4 weeks. Subjects were randomized 2:1 (active:vehicle) to receive one drop of brimonidine tartrate 0.025% or vehicle, bilaterally, 4 times daily, for up to 4 weeks. Drop comfort (0-10 scale) was assessed at Visit 1 immediately following instillation and 30 seconds and 1 minute post-instillation. At all study visits, safety assessments, adverse events (AEs) query, alertness evaluation, IOP, and vital signs measurements were performed by the investigator. Blood and urine samples were collected from a subset of subjects for clinical hematology, blood chemistry, and urinalysis. Subjects used a dosing diary to record in-home dosing between study visits.
Results:
A total of 507 subjects were randomized, including 50 pediatric and 49 geriatric subjects. Two subjects in the brimonidine group reported 3 treatment-emergent serious adverse events (SAEs); all were non-ocular and considered unrelated to study medication. No ocular treatment emergent AEs were reported in subjects <18 years of age. No safety concerns were raised based on clinical examinations. Investigator evaluations of alertness showed no evidence of brimonidine causing somnolence. In the brimonidine-group, no substantial changes in IOP were reported during the study. Brimonidine was very comfortable (mean score 0.4), and no significant differences in drop comfort were reported between the brimonidine and vehicle groups.
Conclusions:
Brimonidine tartrate 0.025% ophthalmic solution was safe, comfortable, and well tolerated when dosed 4 times a day for 4 weeks in this study.