by Dan Roberts
Updated May 2011
A means of delivering drugs into the retina on a time release basis is being developed and proven safe and effective. It is achieved by a method called Encapsulated Cell Technology (ECT), being tested by Neurotech SA with support from the National Eye Institute (NEI), Bethesda, Maryland.
A drug called ciliary neurotrophic factor (CNTF) is produced and released by a device called Renexus (formerly NT-501) into the vitreous of the patient's eyes. CNTF is produced by genetically modified cells contained in the ECT. The ECT acts, therefore, like a miniature factory for production and distribution of the drug. The device may prove to be a safer, more effective and more convenient drug delivery system than the injection procedure currently used for administration of the antiangiogenic and anti-inflammatory drugs in AMD patients.Results from Phase 1 trials showed not only that the ECT device works and is safe, but that CNTF is a potentially effective drug treatment for slowing down all forms of hereditary retinal diseases by its trophic action on nerve cells. Trophic factors are molecules that can protect nerve cells from degeneration. When treated with CNTF, subjects showed an improvement in acuity of one line compared to no improvement in the partner eye.
In March 2009, Neurotech announced that 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. These results from the Phase 2 trials were reported to the Association for Research in Vision and Ophthalmology (ARVO) meeting on May 6, 2009 in Ft. Lauderdale.
In May 2011, results from Phase 3 presented to the annual ARVO meeting showed continued promise, with CNTV leading to stabilization of vision in subjects starting with good visual acuity of at least 20/63, and lessening of the progression of lesion size in geographic atrophy.