Second human study of embryonic stem cells
The U.S. government has approved the second-ever clinical trial in people of a treatment using embryonic stem cells — this time for a rare disease that causes serious vision loss.
The company developing the therapy, Advanced Cell Technology (ACT), a biotechnology company, said the research should begin early next year, following the green light from the U.S. Food and Drug Administration.
Scientists hope to use stem cells to create a variety of tissues for transplant. But human embryos have to be destroyed to harvest those cells, which has made their use controversial.
The trial will examine the safety of a therapy for Stargardt's Macular Degeneration, which affects only about 30,000 Americans. But the company hopes the same approach will work for similar and more common eye disorders like age-related macular degeneration, which affects millions.
Stargardt is an inherited disorder that attacks central vision used for tasks like reading and recognizing faces. Some patients go totally blind, even losing peripheral vision, while others are severely impaired and can only perceive light or see their hands moving in front of their faces.
The disease typically starts in adolescence. The key problem is that impaired scavenger cells fail to remove toxic byproducts from the eye, allowing them to build up and kill other cells. There is no proven treatment.
In the trial, 12 individuals at US medical centers in Massachusetts, New Jersey and Oregon, will be treated with healthy scavenger cells, created in a laboratory from human embryonic stem cells. This early phase of the research is primarily to test the safety of various doses, injecting only one eye of each patient.
"We're also hoping to see some improvement in visual acuity, but that's a bonus," said Dr. Robert Lanza, ACT's chief scientific officer.
Macular degeneration has been seen as stem cell therapy's low-hanging fruit because the cells that need replacing are so accessible, both for delivering the treatment and for monitoring its effects. The eye is also an immune-privileged site, meaning that injections won't elicit an immune response.
Source: Advanced Cell Technology
Gregory D. Pawelski