Advanced Cell Will Test Stem-Cell Therapy for Vision
Doctors will inject retinal cells made from stem cells into the eyes of 12 people with the so-called dry form of macular degeneration, said Gary Rabin, interim chairman and chief executive officer of the Marlboro, Massachusetts-based company. The disease affects about 15 million Americans and new therapies may generate as much as $30 billion in sales, Rabin said.
Advanced Cell on Nov. 22 became the second company to win permission from the U.S. Food and Drug Administration to conduct a trial of human embryonic stem cells, in that case to treat Stargardt macular dystrophy, a rare form of macular degeneration that strikes children. The first company, Geron Corp. (GERN) of Menlo Park, California, said Oct. 11 it used embryonic stem cells to treat the first of 10 patients with spinal-cord injuries.
“We’re at the beginning of something that can revolutionize medicine,” Rabin said in a Dec. 31 telephone interview.
Patients with macular degeneration lose sharp central vision as cellular waste builds in the eyes and damages retinal pigment epithelial, or RPE, cells. Over time, photo receptor cells, which translate visual information into signals that reach the brain, also are harmed.
“Once you lose the RPE cells you no longer have a healthy environment and you start to lose photo receptors,” said Robert Lanza, the company’s chief scientific officer.
By injecting healthy RPE cells into patients, the company hopes to slow the cell loss and the degradation of vision, Lanza said in a Dec. 31 telephone interview. In tests of rats that had versions of the macular disorder, Lanza said he and his colleagues were able to improve the rodents’ vision.
Stem cells derived from embryos that are just a few days old have the ability to form any of the 200 or so cells found in the human body. They are more versatile than adult stem cells, which are found in mature tissues in living people and have a limited ability to morph into other cell types.
Standard methods of isolating stem cells leads to the destruction of the embryo, a process viewed as unethical by some religious and political leaders. President George W. Bush limited federal funding for research, a policy overturned in 2009 by President Barack Obama. Obama’s decision has been challenged in U.S. court.
Advanced Cell has developed a technique for plucking an individual cell out of an early embryo when it has only eight cells. That single cell is used to create a line of stem cells and the young embryo can develop normally, Lanza said.
This technique creates stem cells without destroying embryos, an advance that may allow the company to avoid the controversy. A similar method is sometimes used to assess whether embryos that may be used for in vitro fertilization carry any genetic diseases.
While the retinal cells to be used in Advanced Cell’s clinical trials came from a stem-cell line that was created this way, the embryo itself was destroyed because the company was still working on the technique, Lanza said. He and his colleagues have since perfected the process and created new lines of stem cells from embryos that have been frozen and retained, he said.
Because the early clinical testing for the retinal cells was conducted on animals using a cell line from an embryo that was discarded, the company is continuing to use that line for its human testing, Lanza said. Switching to a different line would require extensive new laboratory work to show the FDA that the lines are exactly the same and to develop them under sterile “good manufacturing practice,” or GMP, conditions. If the vision studies pan out and Advanced Cell develops it into a commercial product, the company may do the work and switch.
“We have lines we can convert to GMP conditions,” Lanza said. “We could thaw those tomorrow and scale them up.”
Advanced Cell’s trial will start by treating a single patient with an injection of 50,000 cells, Lanza said. If no safety problems are seen, two more patients will receive the same dosage, he said. Subsequent patients will get higher doses to find the most effective safe therapy, Lanza said.
Advanced Cell’s therapy is aimed at more than 80 percent of macular degeneration patients who have the dry form of the disorder. In some patients, the disease progresses to the more serious “wet” form, which can cause almost complete vision loss. By treating patients with the dry form and slowing or reversing their vision loss, researchers hope to prevent blindness, Lanza said.
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