I’d like to recommend an article, Stem-Cell Gamble
, from the upcoming issue of Technology Review (from MIT). It’s a nicely balanced lay person’s overview of embryonic stem cell (eSC) science and the formation of clinical trials to transplant the cells in humans. It’s a well-informed take on both the eSC work that led to the Geron trial for acute spinal cord injury, and just last week, to a trial by Advanced Cell Technology to address a common eye disorder that leads to blindness.
We’re all familiar with Geron’s gambit. To date, two patients have been given eSC doses to test the safety of embryonic cells that have been cultured to form a type of support cell in the spinal nerve circuitry (oligodendrocye precursor cells). A secondary endpoint measures functional recovery. The article includes a short byline piece from T.J. Atchison, the first person in history injected with eSC in a U.S. trial. He’s glad he did it but he’s worried about the risk of tumor.
The ACT trial, at UCLA, enrolled two people last week to test the safety of embryonic cells cultured to form retinal pigment epithelial (RPE) cells, which support and nourish the light-sensitive cells that provide vision. From a press release:
Twenty-four people will be treated during the trials at the Jules Stein Eye Institute. One trial will target dry age-related macular degeneration (AMD), the commonest form of blindness in the developed world and a leading cause of vision loss in people aged 55 and over. The other will treat people with Stargardt's macular dystrophy, an inherited condition that usually develops between the ages of 10 and 20.
Professor Steven Schwartz, who will lead the trials at the Institute, said they “will mark a significant step towards addressing what is one of the largest unmet medical needs of our time…otherwise untreatable and common forms of legal blindness.” He added: “The incidence of dry AMD is expected to double over the next 20 years as the population ages.”
Read about the UCLA trial in the latest issue of Time
The Technology Review magazine story contains several news nuggets:
Hans Keirstead, whose lab at UC Irvine made the cells that Geron is using, was offered millions of dollars to treat a wealthy Texan in Mexico. Hans said he thought about it.
The FDA is getting heat for holding up the show:
"The problem is that the agency is overworked and understaffed and isn't so familiar with cell therapy," says Richard Garr, CEO of NeuralStem, a company that recently began tests of fetal spinal-cord cells in patients with Lou Gehrig's disease, or ALS. For NeuralStem's study, like Geron's, the agency required that patients be treated at least 30 days apart, to allow time to tell whether problems would arise. It will take the company at least a year and a half to complete the study, given that 18 patients are expected to enroll. "And here is a disease that kills you in three to five years, on average, after diagnosis," says Garr. "So it feels like they are slowing you down. I think the FDA believes the caution is justified. I can tell you that the patient advocacy groups are frustrated."
A Panamanian jockey has aggressively lobbied to be part of stem cell trials: Michael Martinez, 24, who was paralyzed after falling from a horse in San Francisco last year, was denied entry into the Geron trial, in part because his injuries were too extensive. Martinez is now a candidate to join the soon-to-enroll “early chronic” SCI study in Switzerland sponsored by StemCells Inc. Implanted stem cells are obtained from human fetuses.
Martinez, a Panamanian who speaks little English, says he believes the operation "could help me regain sensation in my legs, and return to capacities I had before." As with most paraplegics, being unable to walk is the least of his problems. His biggest difficulty is bladder infections, since he must urinate through a catheter. Martinez says he's aware that there are dangers associated with the stem-cell treatment, but as a jockey, he's used to long odds. "I know it has certain risks, but I don't want to think about those," he says. "I want to stay focused on the positive."
The way I see it trying to jump into a clinical trial muddies up the whole process – might as well throw all attempts at clinical equipoise out the window. A trial is not a treatment. En espanol: Un ensayo no es un tratamiento.
Keirstead says his “ridiculous sense of optimism” makes it hard for him to advise patients on the Geron trial. Bottom line, he says: "We still don't know if it works in humans."