DRY-AMD

The Leading Cause of Blindness for People Over 50

Dry Age-Related Macular Degeneration (dry-AMD) is the number one cause of unpreventable blindness in the world. In the United States, more patients turn blind due to AMD than due to glaucoma and cataract combined. As dry-AMD is a chronic disease of aging, the number of people affected by AMD is expected to dramatically increase over the next few years. Because of the absence of treatment, the disease is however not as well known as Parkinson's or Alzheimer's diseases, despite the fact that there are more patients affected by dry-AMD than patients suffereing from by Parkinson's, Alzheimer's, breast cancer and prostate cancer combined. The disease mostly affects people over 50 years of age and there is no FDA approved drug for dry-AMD.

There are two forms of AMD: dry-AMD and wet-AMD. If both forms may eventually lead to partial or complete blindness, these two diseases are very different in nature:

  • Dry-AMD is a degenerative disease, where the photoreceptors located at the back of the eye (the retina) degenerate. Dry-AMD accounts for about 90% of all cases of AMD, although not all people experience visual symptoms
  • Wet-AMD is characterized by abnormal blood vessel formation and bleeding in the retina, resulting in rapid degeneration of the photoreceptors in almost all cases. Wet-AMD accounts for 10% of the cases and can usually be treated with the drug Lucentis (or Avastin off-label).

Despite its high prevalence, dry-AMD remains untreated due to historically poor understanding of the disease, which prevented the discovery of rational drugs. Recent data has helped elucidate the origins of the disease and how it first develops and subsequently progresses. Most of this information was acquired during long term clinical studies (the AREDS studies) sponsored by the National Eye Institute (NEI).

The data generated by AREDS showed that a specific blend of vitamins and antioxidants (available over the counter) could at least slow the rate of progression of AMD. Although this discovery was encouraging, an actual pharmaceutical treatment is still critically needed to slow or stop the progression of vision loss in dry-AMD. Such a treatment would benefit millions of patients worldwide.

Drug developers usually develop treatments that benefit one subset of the patient population. For example, a drug that stops the disease formation, also called a "disease modifying drug" would most likely benefit patients with little vision loss, whereas a treatment that could help restore some lost vision would benefit patients with advanced vision loss. Clinicians grade AMD in approximately 3 stages:

  • Early-stage AMD is usually the stage at which patients are first diagnosed. At this stage, some patients may have some mild signs of visual discomfort or slightly blurred vision. There are about 20 million people diagnosed with early-AMD in the US. Fortunately, most patients will remain at this early stage and never progress to the more serious forms.
  • Intermediate AMD is manifested by small 'gaps or holes' in patients' vision, problems distinguishing colors, poor night vision, wavy lines instead of straight lines. Patients may start losing some of their central vision while their peripheral vision remains relatively good. Loss of central vision means poor ability to read, write, drive, recognize faces. Usually one eye will degenerate slightly faster than the other eye, although the other eye is likely to follow soon thereafter. The severity of this intermediate form is graded by a specialized physician from grade 1 to grade 4 during a routine eye exam. Grade 3 and grade 4 are the most severe forms of intermediate AMD and have the highest probability of progressing to the late form of the disease (see figure below). Intermediate-AMD often progresses slightly faster than early-AMD. About 8 million people live with intermediate AMD in the USA.
  • Late-stage AMD is the most serious form of the disease. It can take the form of wet, dry, or a combination of both. The late form of dry-AMD, also called geographic atrophy, is often characterized by incapacitated vision and legal blindness. About 1 million patients in the USA live with the late form of dry-AMD, a number expected to double by 2020 due to the aging population. These patients have lost the ability to read, write, watch a movie, see at night, recognize faces, drive and be independent.

Once diagnosed by a retinal specialist, patients with AMD have to be monitored at least annually (more often if diagnosed with wet-AMD). However, the lack of treatment option for dry-AMD makes patients more likely to fall into depression, and physicians are therefore even more eager to offer new treatments.

Alkeus' lead compound, ALK-001, is an investigational new drug which has shown potential to slow the progression of dry-AMD in animals. Alkeus expects to organize a clinical trial for dry-AMD in the near future. For more information about these trials, please do not hesitate to email us at info@alkeus.com