January 26th, 2012
Stem-Cell Therapy Eye Treatment Proves Safe
By Douglas Clark | Comments (1)
Good news for stem-cell therapy has arrived in the form of a successful clinical trial. Earlier this week, the Lancet
published a paper from researchers at the David Geffen School of Medicine
at the University of California, Los Angeles, and from Advanced Cell Technology
, in Marlborough, Massachusetts. The paper reports that two subjects in the trial each safely received injections of embryonic stem cells into an eye.
Good news, but a small step
While the news is truly good, expectations must be tempered. Why? An article today in Technology Review
points to one major reason: the intent of the study. Stem-cell therapy has received a number of blows, so any news seems like good news, but the results of this most recent trial have to be seen for what they are. The study has been deemed a success solely on the basis that the therapy has proved to be safe:
The new study was written three months after treating the patients, both of whom have degenerative eye diseases and limited sight. Another three months has now passed, and Robert Lanza, chief scientific officer of Advanced Cell Technology, says both are still doing well, with no apparent side effects.
While the study was created to look at treatment safety, Technology Review reports that "Lanza, the paper, and a related commentary also published in The Lancet
all cited the women's reports of benefits from the procedure. One woman's vision improved enough to see a hand waved in front of her face; the other climbed from 20/500 to 20/320 on an eye chart."
The reporting of these results has struck many in the field as premature. The study, for example, has only two patients, and it has to prove that the changes are a true and permanent result of the treatment. Treatment safety is truly the most important result thus far, since researchers were unsure whether stem cells would cause uncontrolled cell growth, leading to a teratoma, a form of benign tumor.
What's next in the study?
The article reports that a second round is in the works:
In the [initial portion of the] study, human embryonic stem cells were coaxed into becoming retinal pigment epithelium, or RPE cells. They were carefully examined for impurities or potential dangers, and then injected into one eye in each patient. The two received 50,000 RPE cells each. The next round of patients will receive 100,000 RPE cells, and later patients in the trial will be given 200,000 cells each.
Of the 24 people in the trial, half have dry, age-related macular degeneration—the most common cause of vision loss in older Americans—and half have Stargardt macular dystrophy, a far rarer disorder that strikes children and teenagers. There are no effective medical treatments for either condition. Lanza says the company will soon begin another round of research in the U.K. involving 24 patients with the same conditions.
You can read full coverage here