The U.S. Food and Drug Administration has given its approval to a second clinical trial involving cells derived from human embryonic stem (hES) cells. Advanced Cell Technology (ACT), a biotech company based in Marlborough, Massachusetts, announced today that it had received approval for testing retinal cells in patients with Stargardt's macular dystrophy, a rare disease that causes progressive vision loss in children.
Cell therapy seems promising for the disease for several reasons. First, the eye is an immune-privileged site, so researchers hope that patients won't have to take antirejection drugs after receiving the transplant, says Robert Lanza, ACT's chief scientific officer. Second, Lanza says, because the retina can be observed at the single cell level it should be possible to follow the transplanted cells' behavior very precisely.
The company says it plans to treat 12 patients with advanced disease at clinical sites in Portland, Oregon; Worcester, Massachusetts; and Newark, New Jersey. The patients will receive up to 200,000 retinal pigment epithelium (RPE) cells that the company derived from hES cells, transplanted directly into the eye, Lanza says.
Tests in animal models have been promising. Mice with a version of Stargardt's that received human RPE cells kept their vision, whereas untreated mice went blind. The researchers saw no adverse effects, Lanza says. He says the company is filing an application to try the treatment in age-related macular degeneration, a disease with similar characteristics that affects as many as 30 million people in the United States and Europe.
ACT applied for permission for its Stargardt's trial a year ago, hoping that it might be the first company to test hES cells in patients. It didn't quite make it. In October, researchers at Geron Corp. and the University of California, Irvine, started the first clinical trial involving hES cells to treat spinal cord injury patients.
ACT was one of the first companies involved in embryonic stem cell research, but it has had ups and downs, almost going out of business several times. "We had our telephones turned off a few times," Lanza says. "But we made it. It was a lot of hard work, and nature cooperated a bit."