The report, published online in the medical journal The Lancet, is the first to describe the effect on patients of a therapy involving human embryonic stem cells.  The paper comes two months after the Geron Corporation cast a pall over the field by abruptly halting the world’s first clinical trial based on embryonic stem cells — one aimed at treating spinal cord injury. Geron, which has not published results from the aborted trial, also said it would abandon the entire stem cell field.  The results reported Monday could help lift some of that pall. They come from the second clinical trial involving the stem cells, using a therapy developed by Advanced Cell Technology to treat macular degeneration, a leading cause of blindness.  “It’s a big step forward for regenerative medicine,” said Dr. Steven D. Schwartz, a retina specialist at the University of California, Los Angeles, who treated the two patients.  Both patients, who were legally blind, said in interviews that they had gains in eyesight that were meaningful for them. One said she could see colors better and was able to thread a needle and sew on a button for the first time in years. The other said she was able to navigate a shopping mall by herself.  Still, it is hard to judge much from only two patients, especially when there was no control group.  Indeed, Dr. Schwartz said that the improvement in vision of one of the women might be a placebo effect.  Advanced Cell Technology, which paid for the study, has been criticized in the past for overstating results, in part because it has been desperate to raise money to stay in business.  The company’s stock rose 3.4 cents, or 23 percent, to 18 cents on Monday.  Dr. Schwartz conceded that it was “extremely unusual” for researchers to publish a study after treating only two patients out of a planned 24. But he said that was justified by the huge interest in the stem cells.  Human embryonic stem cells can theoretically be turned into any type of cell in the body and might one day be used to treat various diseases. But the field has been controversial because the creation of the stem cells usually entails the destruction of human embryos.  In this case, researchers at Advanced Cell Technology turned embryonic stem cells into retinal pigment epithelial cells. Deterioration of these retinal cells can lead to damage to the macula, the central part of the retina, and to loss of the straight-ahead vision necessary to recognize faces, watch television or read.  Some 50,000 of the cells were implanted last July under the retinas in one eye of each woman in operations that took about 30 minutes.  One woman, Sue Freeman, who is in her 70s, suffered from the dry form of age-related macular degeneration, a leading cause of severe vision loss in the elderly.  The other, who asked that her name not be used to protect her privacy, was a 51-year-old graphic designer in Los Angeles with Stargardt’s macular dystrophy, which tends to occur in younger people.  There are no approved drugs for either disease.  One safety concern in using embryonic stem cells is that if any of the cells get into the body, they could form tumors. The researchers reported that this did not happen in the first four months after the surgery and that there were no obvious safety problems.  The two women were given low doses of drugs to suppress the body’s immune system and prevent them from rejecting the implanted cells, even though the eye is somewhat shielded from the immune system.  Thomas A. Reh, a professor at the University of Washington who works on retinal regeneration but was not involved in the study, said the results looked encouraging, though the patients needed to be followed for a longer time.  “It definitely looks like the cells are at least sticking around and not causing any trouble,” he said.  Before the treatment, the woman with Stargardt’s was able to see the motion of a hand being waved in front of her but could not read any letters on an eye chart. Twelve weeks after the treatment, she was able to read five of the biggest letters on the eye chart with the treated eye, corresponding to 20/800 vision, according to the paper.  “I kind of did have a day when I woke up and said there really is a difference here,” the woman said in an interview about three months after the surgery.  Ms. Freeman, who lives in Laguna Beach, Calif., went to 20/320 from 20/500 vision six weeks after the treatment.  However, vision in her untreated eye also improved, at least temporarily, and the implanted cells could not be seen in her eye after the first day. That is why Dr. Schwartz said the improvement might have been a placebo effect.  The trial is now expanding beyond U.C.L.A. and to gradually higher doses of cells.
A treatment that improved the vision of two women with forms of macular degeneration could be a breakthrough for regenerative medicine after a recent setback.