Another hESC Trial to Begin in the US

Advanced Cell Technology, of Marlborough, Mass., announced yesterday that it received an FDA thumbs-up to begin a small clinical trial of human embryonic stem cells (hESCs) in a rare eye disorder. The trial is the second study of hESCs in humans to get a regulatory nod, making the idea of hESC therapy less and less of a sci-fi fantasy—and more and more of a threat to those who judge the potential benefit of hESC to be merely speculative.

The disorder of interest, Stargardt's macular degeneration, which affects about 30,000 Americans, is potentially a springboard for the study of hESCs in age-related macular degeneration (AMD), which affects nearly 2 million Americans. Stargardt's disease, an inherited blinding condition, affects the retinal pigment epithelium (RPE), which is also implicated in AMD.

Treating an eye disorder with hESCs (which are intended to replace the damaged RPE cells) is anticipated to be a relatively smooth investigatory ride, given 1) the accessibility of the eye (both to treatment and the assessment of treatment), and 2) the fact that the eye is immune privileged (making immunosuppressive therapy unnecessary).

"Long-term functional rescue" of RPEs, using hESC, has already been demonstrated in a rat model of retinal degeneration.

The cells sustained visual function and photoreceptor integrity in a dose-dependent fashion without teratoma formation or untoward pathological reactions. Near-normal functional measurements were recorded at >60 days survival...

Image of undifferentiated hESCs from http://www.nih.gov/catalyst/2007/07.01.01/page1.html.