A long-awaited clinical study that puts cells derived from induced pluripotent stem (iPS) cells in humans for the first time started recruiting patients August 1, after passing its final regulatory hurdle. Masayo Takahashi, an ophthalmologist at the RIKEN Center for Developmental Biology in Kobe, Japan, will use sheets of retinal cells derived from iPS cells to treat patients suffering from age-related macular degeneration. iPS cells, derived from the skin cells of the patients, will be genetically matched and thus, it is hoped, will not be rejected. There are a half dozen clinical trials using stem cells to treat retinal disease. The use of iPS cells makes it the most exciting, says Robin Ali of University College London. His team recently showed the potential to use iPS cell–derived photoreceptors to repair vision loss in mice (Nat. Biotechnol. 31, 741–747, 2013). “And I think [iPS cells have] the best chance of success compared with other retinal pigment epithelium transplant approaches,” he adds. Takahashi's team will transplant 1.3-mm × 3-mm sheets of retinal epithelium cells to the damaged retina in an attempt to halt its deterioration and prevent further photoreceptor destruction. The transplant will probably not repair lost vision. The sheets, which will be transplanted to three patients with start dates staggered by at least eight weeks, will take 10 months to make. If proven safe, another three patients will be treated. For safety reasons, Takahashi will treat only one eye in each person. “If some infection occurs, patients will lose their sight completely,” she says. The experiment is a “clinical study,” not a formal clinical trial. Even if the experiment is successful, it will not lead to formal approval as a biologic drug. Takahashi hopes that the study will, however, encourage more formal trials in future.