Stem cell retinal implant therapy is safe, new study shows: After only four months, an embryonic stem cell treatment for eye disease has improved the sight of two women legally blind for many years — according to the women themselves and scientists behind the world’s first human trial for eye disease stem cell treatments.
The promising results come from the second clinical trial involving a stem cell therapy developed by U.S. company Advanced Cell Technology to treat macular degeneration, a leading cause of blindness.
The findings — which also represent one of the first studies in the United States to use human embryonic stem cells (hESCs) in people — may bolster the field of stem cell research.
Because hESCs can theoretically be turned into any type of cell in the body, medical scientists see in them the possibility of developing treatments for many deadly and incurable diseases.
In the new trials, the embryonic cells were used to create retinal pigment epithelial cells that protect and provide nutrition for cells that sense light.
“It’s a big step forward for regenerative medicine,” says Dr. Steven D. Schwartz, a retina specialist at the University of California, Los Angeles, who treated the two patients. The findings of the trial, sponsored by the Advanced Cell Technology, were published online in the medical journal The Lancet.
The study also makes up one of only two hESC treatments approved by the U.S. Food and Drug Authority.
The other study — on treating spinal cord injury — was the world’s first clinical trial based on embryonic stem cells. But it was abruptly halted last November (2011) after its sponsor, Geron Corporation, took a lot of flak for using its controversial hESCs. Geron hasn’t published the results of its aborted trial and even said it would abandon the entire stem cell field.[Related Story: Geron Stem Cell Trials]
While the use of hESCs will likely remain controversial for many years, for both patients, it’s been nothing but a blessing. Four months after treatment, both women reported improvements in vision and actually performed better on standardized eye tests.
In interviews with the National Public Radio (NPR), the women say they had meaningful gains in eyesight. One says she could see colors better and for the first time in years, can now thread a needle and sew on a button. The other says she is now able to navigate a shopping mall by herself.
Sue Freeman, 78, one of the two who received the stem cell treatment, suffered for years from the dry form of age-related macular degeneration, a leading cause of severe vision loss in the elderly.
The other, a 51-year-old graphic designer in Los Angeles, California, began losing her sight in her 20s from Stargardt’s macular dystrophy, an inherited disease that causes progressive loss of central vision and which tends to occur in younger people. She said she wanted to remain anonymous to protect her privacy.
There are no approved drugs for both eye diseases.
Before the treatment, the woman with Stargardt’s could see movement like a hand being waved in front of her but couldn’t read any letters on an eye chart. Three months after the treatment, she was able to read the five biggest letters on the eye chart with the treated eye, researchers say. This corresponds to 20/800 vision, they note.
“I kind of did have a day when I woke up and said there really is a difference here,” the woman tells NPR in an interview. She says she can now do chores and even ride a bike again. Her day-to-day life has improved enormously, she adds.