Gene Therapy May Aid In Sickle Cell Disease Treatment

Dec 10, 2019
Originally published on December 10, 2019 11:39 pm
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RACHEL MARTIN, HOST:

We've been hearing a lot of reporting recently about using the latest genetic technology to try and treat sickle cell disease. Scientists are also making progress using older DNA techniques to help people with this common, devastating blood disorder. NPR health correspondent Rob Stein is in our studios to talk about the latest news about experimental genetic treatments for sickle cell disease. Hi, Rob.

ROB STEIN, BYLINE: Good morning, Rachel.

MARTIN: So just start off by reminding us about the effects of sickle cell disease - who gets it, how common it is.

STEIN: Yeah, it's - Rachel, it's a really awful disease that affects the red blood cells. You know, these are the cells that carry oxygen in our body.

MARTIN: Yeah.

STEIN: And a genetic defect causes these red blood cells to become defective sickle-shaped cells, and they're really bad at carrying oxygen. They get stuck inside blood vessels. They cause horrible attacks of pain, organ damage, heart attacks, strokes. It affects millions of people around the world, including about 100,000 in this country.

MARTIN: So has there been any way to treat sickle cell?

STEIN: So in this country, sickle cell mostly affects African Americans, and many people say it's been a neglected disease in this country. Some people can get bone marrow transplants, but they're really expensive, and they're risky. And in this country, most sickle cell patients, they don't make it past middle age. That seems to finally have started to change. There are two new drugs that are helpful - were recently approved for sickle cell. But there's really still no cure for most sickle cell patients.

MARTIN: But there are some encouraging possibilities on the horizon, right?

STEIN: Yeah. So, Rachel, as you know, we've been following one sickle cell patient named Victoria Gray closely this year. She's the first person in the United States to get treated for a genetic disorder with a revolutionary kind of genetic engineering called CRISPR.

MARTIN: Right.

STEIN: Scientists infused billions of her own cells that have been genetically modified with CRISPR into her body this summer to try to help her, and just recently, doctors reported the first hints that it looks promising. Now, it's super early, so we're not even close to really knowing if it works. But so far, so good.

MARTIN: Great. So there's other, similar research out there, too?

STEIN: Yeah. Yeah. So scientists have been working for years, really, to try to use what's called gene therapy to treat sickle cell disease. Now, gene therapy is the first strategy scientists developed to try to treat diseases at the genetic level. It usually involves using harmless viruses to ferry new genes or genetic information into the body. Gene therapy caused some disasters early on, but it's finally started to work, and several experimental gene therapies are showing promise for sickle cell disease now.

MARTIN: Well, how so? I mean, what specifically can you tell us about that?

STEIN: Yeah. Yeah. So there's this big scientific meeting that's just wrapping up today in Florida, where scientists are reporting more encouraging results. Now, one approach involves giving sickle cell patients' cells a new gene to compensate for the defective one, to make their bodies produce a healthy version of a protein called hemoglobin, and that's what red blood cells need to carry oxygen in the body. Another strategy is sort of similar to the CRISPR gene-editing approach that Victoria got; it involves using gene therapy to make cells produce a different kind of hemoglobin called fetal hemoglobin to make up for that defective hemoglobin.

MARTIN: OK. So this is working? I mean, what do we know about results?

STEIN: Yeah. Well, again, so far so good. Yeah. For example, there are doctors in - at Boston Children's Hospital trying gene therapy to make fetal hemoglobin, and they say it's looking good for the first handful of patients that they've treated so far.

And a company called Bluebird Bio is even further along. They're reporting promising results from 17 patients who got the most advanced version of that approach. That uses gene therapy to add a new gene to make up for the defective hemoglobin gene. And it looks like it's working. It's producing healthy hemoglobin and healthy red blood cells, and it even looks like it might be alleviating suffering for sickle cell patients treated so far. Now, you know, with all this stuff, I have to say, there's a whole long way to go.

MARTIN: Yeah.

STEIN: A lot more patients will have to be treated and followed for years to make sure that it's safe, to really know how well it works and how long it might keep working. But it looks like there's at least hope finally on the horizon for sickle cell patients. If it does work, the next big question is how to pay for it. These new therapies are coming with really hefty price tags.

MARTIN: NPR health correspondent Rob Stein. Rob, thank you.

STEIN: Sure thing, Rachel. Transcript provided by NPR, Copyright NPR.