Non-arteritic ischemic optic neuropathy can be difficult to treat. A new drug under investigation aims to prevent further loss of vision from the condition.
Reviewed by Neil R. Miller, MD
Non-arteritic ischemic optic neuropathy (NAION) can be challenging to treat. Ophthalmologists have used several therapies with patients-ranging from steroids to ranibizumab and bevacizumab-all with mixed results reported in the literature, said Neil R. Miller, MD.
Yet, effective treatments for NAION are crucial because the condition is the most common reason for sudden optic nerve-related visual loss in the older population.
“It affects 10,000 people in the United States every year, and it’s second only to glaucoma in optic nerve damage in older people,” said Dr. Miller, Frank B. Walsh professor of neuro-ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore.
Effective treatments for NAION are also increasingly important because of certain health conditions growing in the United States and worldwide, including obesity, diabetes, and hypertension.
A. A typical visual field of non-arteritic ischemic optic neuropathy (NAION). B/C. Disc photos of acute NAION. (Images courtesy of Neil R. Miller, MD)
“Patients with NAION tend to be those with underlying vascular disorders,” he said.
Additionally, even though 40% of patients with NAION improve without treatment, 60% do not. About 20% of patients will have their second eye affected as well.
“We have no consistent treatment and once someone loses vision in one eye, let alone both eyes, doing daily activities is affected,” Dr. Miller said.
Now, a multicenter phase II/III trial is under way to try a new neuroprotective drug as a potential treatment.
The drug (QPI-1007, Quark Pharmaceuticals) is a synthetic small interfering RNA (siRNA) that targets the mRNA of the caspase 2 gene. The drug is under development as a neuroprotectant to treat NAION and glaucoma, as well as other optic neuropathies that kill retinal ganglion cells. The FDA has given the drug an orphan designation for NAION, according to Quark.
The trial has five patient cohorts as follows:
The trial will enroll about 530 subjects over the next 2 years; subjects will be randomly assigned into one of the aforementioned groups. Researchers have recruited more than 100 patients so far, which is on target with the research plans, Dr. Miller said. The trial’s main outcome is loss of vision, followed by safety and tolerability.
Dr. Miller is part of the Neuro-Ophthalmology Research Disease Investigator Consortium (NORDIC), a group organized by the North American Neuro-Ophthalmology Society and that receives funding from the National Eye Institute and other sources. The trial is co-sponsored by Quark and NORDIC and eventually will take place at about 90 sites worldwide, although 60 are participating so far. Most sites are in the United States, with participants also in India, Israel, Germany, Italy, Australia, and Singapore.
Results for an interim analysis may be available by the middle of this year, Dr. Miller said.
Neil R. Miller, MD
Dr. Miller did not indicate any financial interest in the subject matter.