| Abstract: | Myopia is the leading cause of low vision worldwide and can lead to significant pathological complications. Therefore, to improve patient outcomes, the field continues to develop novel interventions for this visual disorder. Accordingly, this first‐in‐human study reports on the safety profile of a novel dopamine‐based ophthalmic treatment for myopia, levodopa/carbidopa eye drops. This phase I, first‐in‐human, monocenter, placebo‐controlled, double‐blind, paired‐eye, multidose, randomized clinical trial was undertaken in healthy adult males aged 18–30 years (mean age 24.9 ± 2.7) at the University of Canberra Eye Clinic, Australia. Participants were randomly assigned to receive either a low (1.4 levodopa:0.34 carbidopa [μmoles/day], n = 14) or standard dose (2.7 levodopa:0.68 carbidopa [μmoles/day], n = 15) of levodopa/carbidopa eye drops in one eye and placebo in the fellow eye once daily for 4 weeks (28 days). Over this 4‐week trial, and after a 4‐month follow‐up visit, levodopa/carbidopa treatment had no significant effect on ocular tolerability and anterior surface integrity, visual function, ocular health, refraction/ocular biometry, and did not induce any non‐ocular adverse events. These results indicate that topical levodopa/carbidopa is safe and tolerable to the eye, paving the way for future studies on the efficacy of this novel ophthalmic formulation in the treatment of human myopia. The findings of this study have implications not only for the treatment of myopia, but in a number of other visual disorders (i.e., amblyopia, diabetic retinopathy, and age‐related macular degeneration) in which levodopa has been identified as a potential clinical intervention.Study Highlights - WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?
Preclinical data indicate that levodopa/carbidopa eye drops can safely inhibit the development of experimental myopia in animal models. - WHAT QUESTION DID THIS STUDY ADDRESS?
This study investigated whether levodopa/carbidopa eye drops are safe and tolerable to the human eye. - WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?
In this phase I, first‐in‐human, monocenter, randomized, double‐blind, placebo‐controlled, multidose trial, levodopa/carbidopa eye drops were found to be safe and well tolerated in healthy adult males over a 4‐week period. Furthermore, no non‐ocular adverse events were reported. - HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?
As topical administration of levodopa/carbidopa eye drops is well tolerated in humans, the efficacy of this novel ophthalmic treatment at inhibiting the development of myopia in patient populations can now be assessed. If found to be effective, this will provide a powerful new method for inhibiting the onset and development of the leading cause of low vision worldwide. This topical formulation may also provide a valuable tool in the treatment of other visual disorders shown to be responsive to levodopa therapy (i.e., amblyopia, diabetic retinopathy, and age‐related macular degeneration). |
