How retinitis pigmentosa destroys vision
Studies show that Americans fear losing their vision more than any other sense, such as hearing or speech, and almost as much as they fear cancer, Alzheimer’s and HIV/AIDS. That’s not too surprising. Our eyes are our connection to the world around us. Sever that connection, and the world is a very different place.
For people with retinitis pigmentosa (RP), the leading cause of inherited blindness in the world, that connection is slowly destroyed over many years. The disease eats away at the cells in the eye that sense light, so the world of people with RP steadily becomes darker and darker, until the light goes out completely. It often strikes people in their teens, and many are blind by the time they are 40.
There are no treatments. No cures. At least not yet. But now there is a glimmer of hope as a new clinical trial using stem cells – and funded by CIRM – gets underway.
We have talked about this project before. It’s run by UC Irvine’s Dr. Henry Klassen and his team at jCyte. In the first phase of their clinical trial they tested their treatment on a small group of patients with RP, to try and ensure that their approach was safe. It was. But it was a lot more than that. For people like Rosie Barrero, the treatment seems to have helped restore some of their vision. You can hear Rosie talk about that in our recent video.
Now the same treatment that helped Rosie, is going to be tested in a much larger group of people, as jCyte starts recruiting 70 patients for this new study.
In a news release announcing the start of the Phase 2 trial, Henry Klassen said this was an exciting moment:
“We are encouraged by the therapy’s excellent safety track record in early trials and hope to build on those results. Right now, there are no effective treatments for retinitis pigmentosa. People must find ways to adapt to their vision loss. With CIRM’s support, we hope to change that.”
The treatment involves using retinal progenitor cells, the kind destroyed by the disease. These are injected into the back of the eye where they release factors which the researchers hope will help rescue some of the diseased cells and regenerate some replacement ones.
Paul Bresge, CEO of jCyte, says one of the lovely things about this approach, is its simplicity:
“Because no surgery is required, the therapy can be easily administered. The entire procedure takes minutes.”
Not everyone will get the retinal progenitor cells, at least not to begin with. One group of patients will get an injection of the cells into their worst-sighted eye. The other group will get a sham injection with no cells. This will allow researchers to compare the two groups and determine if any improvements in vision are due to the treatment or a placebo effect.
The good news is that after one year of follow-up, the group that got the sham injection will also be able to get an injection of the real cells, so that if the therapy is effective they too may be able to benefit from it.
When we talked to Rosie Barrero about the impact the treatment had on her, she said it was like watching the world slowly come into focus after years of not being able to see anything.
“My dream was to see my kids. I always saw them with my heart, but now I can see them with my eyes. Seeing their faces, it’s truly a miracle.”
We are hoping this Phase 2 clinical trial gives others a chance to experience similar miracles.
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