Age-related macular degeneration (AMD) is the main cause of blindness in elderly people in Western countries with a prevalence of 30% in individuals over seventy years of age. The degeneration of the macula (the central portion of the retina) causes loss of vision in the center of the visual field. The macula is used for reading, driving, recognizing faces or color and usually for fine, detailed work. AMD begins as dry AMD and progesses to either wet AMD or geographic atrophy (GA), the latter involving a breakdown or wasting away of the photoreceptors. There are currently no approved GA therapies for the nearly one million individuals affected in the United States¹. Given this, the market opportunity for new treatments for GA are significant—in excess of $1 billion. To learn more about GA please visit the Foundation Fighting Blindness website.

Clinical Studies in Geographic Atrophy
In March of 2009, Neurotech announced positive results and the achievement of proof of concept in a Phase 2 clinical study of NT-501 for the treatment of geographic atrophy (GA) associated with the dry AMD. NT-501 utilizes Neurotech's proprietary ECT technology platform and consists of encapsulated human cells genetically modified to secrete ciliary neurotrophic factor (CNTF). CNTF is a growth factor capable of rescuing dying photoreceptors and protecting them from degeneration. NT-501 is designed to continually deliver a low, safe and therapeutic dose of CNTF into the back of the eye.

In the study, the high dose of NT-501 stabilized best corrected visual acuity (BCVA) at 12-months, with 96.3% (p=0.078) of treated-patients losing fewer than three lines of vision, or 15 letters, versus 75% of the patients in the sham-treatment group. The strong trend in visual acuity stabilization at 12 months was preceded by a dose-dependent, statistically significant (p<0.001 and p=0.013 for high and low dose, respectively) increase in retinal thickness as measured by optical coherence tomography (OCT) that was observed as early as 4 months post-implantation. The observed structural change is consistent with preclinical studies of NT-501 in which CNTF was shown to increase the thickness of the retina and the outer nuclear layer of photoreceptors responsible for vision. This increase in retinal thickness may be responsible for photoreceptor rescue and protection as observed in numerous animal models of retinal degeneration. Patients were also evaluated for an increase in BCVA. However, no increase was observed, likely due to existing photoreceptor damage. There were no NT-501 associated serious adverse events reported and both NT-501 and the surgical procedure were well-tolerated.  

The Phase 2 study was a randomized, multi-centered, double-masked, sham-controlled study designed to evaluate trends in efficacy and the safety of NT-501. Patients received either a high or low dose NT-501 implant or a sham treatment in one eye only. A trend in best corrected visual acuity was the primary efficacy endpoint of this study. Neurotech has received Fast Track designation for NT-501 for the treatment of visual loss associated with dry AMD from the U.S. Food and Drug Administration.

¹ "Archives of Ophthalmology", April 2004, National Eye Institute