No Losing Sight
For millions of people worldwide suffering from two of the most prevalent eye diseases —age-related macular degeneration and diabetic macular edema—monthly ocular injections are the last line of defense against going partially blind. But the regular treatments, which typically involve inserting a thin needle into the center of the eye and depositing antibodies to the retina, can be irritating to patients. Now a trio of Johns Hopkins researchers is close to refining a new drugdelivery system to decrease the frequency—while increasing the effectiveness—of those aggravating injections.
Each year, about 2 million new cases of age-related macular degeneration and 1 million cases of diabetic macular edema are reported globally. “We’re talking about extremely prevalent diseases,” says ophthalmologist Peter Campochiaro. “These are the major causes of severe vision loss worldwide.”
Each year, about 2 million new cases of AMD and 1 million cases of diabetic macular edema are reported globally. In the United States alone, AMD is the leading cause of vision loss. According to the National Eye Institute, the number of Americans with AMD grew from 1.75 million in 2000 to 2.1 million in 2014. “We’re talking about extremely prevalent diseases,” says ophthalmologist Peter Campochiaro. “These are the major causes of severe vision loss worldwide.”
After monthly treatments, the injected antibodies suppress runaway blood vessel growth and fluid leakage that can cause AMD and diabetic macular edema to worsen. But the antibodies usually dissipate after about 30 days, requiring patients to return for more injections. “Patients generally can’t keep up with the injections,” Campochiaro says. If left untreated, both diseases lead to scarring and the loss of central vision.
The treatment method developed by Campochiaro and his colleagues, biomedical engineers Aleksander Popel and Jordan Green, would require just three injections a year. Incorporating specific peptides— small molecules composed of chains of amino acids, the building blocks of proteins— this method, newly discovered by Popel, has two advantages. First, the peptide-based medicine forms a natural depot within the eye, gradually releasing peptides that act on the retina over a longer period of time. And second, the medicine acts directly on the endothelial cells lining the interior surface of blood vessels in the eye, making the treatment more effective.
Currently the team’s treatment method is in preclinical animal studies, the first step in making sure it’s safe enough to be used in human clinical trials, which could happen as early as 2019.
“We’ll probably have another year of these safety studies,” Green says. “So far, everything looks great.”