Dr. Baruch D. Kuppermann, from the University of California, Irvine presented several projects targeting advanced dry AMD, or Geographic Atrophy (GA).  As dry AMD progresses, it can move from a few drusen, to larger drusen, to a whole area of non-working cells, or GA.

Because inflammation is a feature of macular degeneration, a variety of "neuroprotective" agents are being studied.  If they work, they will protect the macular cells from dying. Because dry AMD and GA development occurs over a long period of time, potential treatments will likely also be needed over a long period of time.  Retinal implants with time release therapy are under investigation by three projects.

Neurotech Implant-NT-501

This tiny insert contains, not a drug, but cells that produce a drug and release it into the eye over time.  The cells in this implant are retinal pigment epithelial cells (RPE) and they are producing ciliary neurotrophic factor (CNTF).  In a two year Phase II clinical trial, the drug continued to be produced and the visual acuity results were encouraging.  This implant requires a minor surgery to attach the implant to the side of the retina.

Brimonidine Drug Delivery System

This system is designed by Allergan, using the drug brimonidine, which has been shown to be "neuroprotective".  This implant is injected into the eye with a needle and does not require surgery. The implant itself is biodegradable, so as the drug is released over time, the implant disappears, so it doesn't need to be removed.  A Phase II clinical trial is underway.

MAP-GA

Alimera Sciences has developed an implant that delivers the drug fluocinolone acetonide (FA), originally being used to treat diabetic macular edema (swelling of the macula caused by diabetes).  A single clinical trial of this system for macular degeneration is underway. This extremely tiny implant is injected into the side of the retina. Current studies in diabetes indicate that it works up to three years.  Because it is so small, additional implants can be injected as needed, without having to remove the previous implants.

Clearly, the purpose of these clinical trials is not only to find a treatment for dry AMD, but also to find one that does not involve repeated injections in the eye, as is the current therapy for wet AMD.

October 2011