Exaggerated response to a limited clinical study

A preliminary report was published online on 1/23/12 in Lancet about the first two patients in safety studies of injecting retinal pigment epithelium cells derived from human embryonic stem cells into the eyes of patients with different kinds of retinal blindness. What can be concluded from the studies is that no tumor formation or rejection was noted in these two patients four months after the injections. That is not enough information to make any conclusions about the safety of this treatment and safety is the only thing these studies are designed to assess. There are some who have questioned why such limited data would even be published, but the headlines in the press were amazing. They ranged from “Early Success in a Human Embryonic Stem Cell Trial to Treat Blindness” (Time) and “Blindness eased by historic stem cell treatment” (New Scientist) to “Embryonic stem cells: can we make the blind see?” (Forbes).

Why would very limited initial results from preliminary safety studies have such an exaggerated response? Part of it undoubtedly has to do with our culture’s desire to find miraculous cures in science. In fact the Forbes article says “Restoring sight to the blind is, literally, a miracle…when the cells inside the eye are damaged, there is nothing we can do. Until now.” Another part may be due to economics. These studies are being funded by a private company, Advanced Cell Technologies, which stands to benefit from any positive publicity. The company’s Chief Scientific Officer, Robert Lanza, was quoted in the New Scientist article emphasizing the improvement in the vision of one of the patients. The studies are not designed to assess the effectiveness of the treatments to improve vision and vision was only measured to look for deterioration as a possible side effect. One of the other researchers involved noted that the other patient was found to have some slight improvement in vision in both of her eyes, even though only one was treated, suggesting any improvement was due to the immunosuppressant drugs used or a placebo effect.

Scientific discoveries can at times be very beneficial, but we need to take very preliminary studies such as this one as what it is – preliminary. We should not induce false hopes in people with retinal blindness that they are going to be cured. We should not forget that there may be some studies and treatments that should not be done, such as those which require the destruction of human embryos when other methods for deriving retinal pigment epithelial cells could have been used.

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