Neurotech’s is not the only approach to combating degenerative retinal diseases, however. Other researchers are transplanting various kinds of cells into the retina itself. For instance, Thomas Reh, a biologist and expert in retinal-cell development and regeneration at the University of Washington, has used embryonic stem cells to produce light-sensitive cells, which resemble those of the retina. His team is now transplanting the cells into the eyes of blind mice to see whether they improve the animals’ sight. In related work, Advanced Cell Technology, a biotech company based in Alameda, CA, has used embryonic stem cells to produce another type of retinal cells–called pigment epithelial cells–that degenerate in macular degeneration. When transplanted into animal models, these cells appear to protect the light-sensitive cells of the retina and improve vision. Still other researchers are working with cells derived from fetal tissue.
In these approaches, the goal is to integrate new cells into the retina to help restore its function. Rebuilding parts of the retina might result in more dramatic or long-lasting improvement than simply slowing degeneration, says Reh. On the other hand, Neurotech’s strategy “may be less risky because if something goes wrong, you can get the cells out again” simply by removing the device, he says.
Neurotech is also farther along in the clinical-trials process than any other cell-therapy group, so its platform could be available to patients sooner, Reh adds.
Other active research involves gene therapy. For example, Ceregene, a biotech company based in San Diego, is working with the gene for a protein called NT4. Researchers at the company have introduced the gene into the retinas of several animal models and seen improvements in vision, according to Jeffrey Ostrove, president and CEO of Ceregene. The company expects to begin clinical trials in people with retinitis pigmentosa and macular degeneration soon, possibly in 2009.
Rose, however, emphasizes that Neurotech offers more than just a specific treatment regimen; it also offers a novel drug delivery system. “Even if the results of the current trials aren’t 100 percent spectacular,” he says, Neurotech’s approach could be adapted to deliver other growth factors or therapeutic molecules down the road. “That’s the beauty of it. It’s a spectacular platform.”