The outlook for human embryonic stem cells (hESC) changed on Tuesday, October 14, 2014 with the report in the Lancet of positive results from the first FDA approved clinical trial of hESCs. Up to this point, the potential of hESC treatment has been primarily theoretical. There was a biological basis to hope for beneficial effects, but limited evidence to support their therapeutic use in humans.
On Tuesday, researchers reported results from a multi-site, Phase I trial on 18 patients with vision loss due to Stargardt’s macular dystrophy or age-related macular degeneration. In the study, tens of thousands of hESCs were implanted into the eye during surgery. There were three groups, and the dose increased for each group.
Like all Phase I trials, this trial was designed to test the safety of the intervention. In essence, it asked the question could hESCs be implanted in the eye without creating problems. While some complications did arise, including development of cataracts, infection, and inflammation, these were consistent with what you would expect from any eye surgery or the immunosuppressive drugs, rather than something likely caused by the hESCs themselves. As part of their safety tests, the researchers also monitored the participants’ vision. The results were both unexpected and exciting.
Of the 18 people participating, 10 had their vision significantly improve and seven either had limited improvement or remained the same (which, for a degenerative disease, may itself be a good result). Only one person’s vision worsened. The improvement was observed both on standard visual tests, as well as participants’ reported experiences. In an NPR story on the study, one of the researchers described how these improvements manifested themselves as: “a graphic artist who could suddenly make out the woodwork on a piece of furniture in her bedroom, an international consultant who regained the ability to walk through busy airports without help, and an elderly rancher who’s riding his horse again.”
As promising as these results are, they also make me concerned that this news will fuel additional exploitation of desperate patients. A world-wide business offering unproven “stem cell therapies” to patients already exists. These “therapies” have not undergone research to establish that they are safe and that they work. They may not even be the hESCs they purport to be. That has not stopped people from seeking them, and news reports about this study may prompt more patients to seek out hESC treatment. However, they may be ill equipped to distinguish between legitimate trials (like this one) and unproven treatments. My Georgia Tech colleague, Aaron Levine, and I previously concluded that, at least when asked about stem cell therapies, physicians have an obligation to help patients understand these differences. The International Society for Stem Cell Research has created a patient handbook on stem cell therapies that physicians may find useful in discussions with patients who are interested in stem cell therapies.
Leslie Wolf is professor with Georgia State University College of Law and director of the Center for Law, Health & Society. She conducts research in a variety of areas in health and public health law and ethics, with a particular focus on research ethics.