Advanced Cell Technology, of Marlborough, Mass., said it would test its stem cell therapy on 12 adults with severe vision loss caused by Stargardt’s, an inherited disease. The company has turned human embryonic stem cells into retinal pigment epithelial cells, which will be surgically implanted into the eye. The hope is that the implanted cells will replace those injured by the disease.
Human embryonic stem cells are controversial because their creation usually entails the destruction of human embryos, although Advanced Cell Technology is working on a technique to avoid that.
Embryonic cells can also form tumors if injected into the body. Dr. Robert Lanza, chief scientist at Advanced Cell, said the company had to prove to the F.D.A. that its retinal cells contained virtually no residual embryonic stem cells. It took a year for the company to get clearance for the trial from the F.D.A.