Abstract
Purpose:
The novel compound SkQ1 is a positively charged antioxidant accumulated specifically inside mitochondria, where after ROS-dependent oxidation it is reduced by the respiratory chain, making it a renewable active compound. This combination of localization in mitochondria and the ability to regenerate itself make it a potentially effective pharmacological agent for the treatment of pathologies of the eye associated with oxidative stress and lipid and protein peroxidation in the inner membrane of mitochondria. Oxidative mechanisms are believed to play an important role in the pathogenesis of age-related eye disease such as dry eye. Consequently, it was hypothesized that the anti-oxidant properties of SkQ1 in ophthalmic solution could produce a treatment effect in the prevention of the onset or progression of dry eye.
Methods:
A single-center randomized, double-masked, placebo-controlled Phase 2 controlled adverse environment (CAE®) study was conducted in 91 dry eye subjects. Key eligibility criteria included scores of ≥ 2, ≥ 0.5 and ≥ 2 for fluorescein corneal staining (FCS), inferior region FCS, and one symptom from the 4-Symptom Questionnaire. Subjects also had to positively respond to CAE® exposure on 2 visits with exacerbation of FCS and ocular discomfort. Eligible subjects dosed BID with 1.55µg/mL SkQ1, 0.155µg/mL SkQ1 or placebo for 28 days and recorded symptoms in diaries. Efficacy measures were inferior region FCS pre-CAE® at day 28 and diary data for the 28-day period.
Results:
Differences in dry eye sign treatment effect were observed for total FCS scores in the ITT population when compared pre- and post-CAE® at day 28 (p=0.0452). Differences in dry eye symptom treatment effect were observed for ocular discomfort when day 28 and baseline scores were compared (p=0.0068). SkQ1 was safe and comfortable; there were no differences in occurrence of AEs or in tolerability scores between treatment groups.
Conclusions:
These efficacy and safety data support the hypothesis that subjects with dry eye are responsive to SkQ1 and warrant further investigation.