RACHEL MARTIN, HOST:
Scientists are reporting another big advance using the revolutionary gene-editing technique called CRISPR to treat diseases. For the first time, doctors have simply infused CRISPR into patients' bloodstreams to try and help them. And it appears to have worked.
NPR health correspondent, Rob Stein, has more.
ROB STEIN, BYLINE: Patrick Doherty had always been really active - trekking the Himalayas, hiking trails in Spain. But he suddenly started feeling pins and needles in his fingers and toes. And his feet got cold. And then one day, he noticed he was running out of breath just walking his dog in County Donegal in Ireland, where he lives.
PATRICK DOHERTY: I'm kind of getting a bit breathless going up a small hillside here in Donegal, which - there are many (laughter). So I realized something was wrong. Something was wrong.
STEIN: Turns out, he had inherited a rare but devastating disease that killed his dad, known as amyloidosis. A deformed protein was damaging parts of his body, like nerves in his fingers and toes and his heart. He had watched two uncles and neighbors also die awful deaths from amyloidosis.
DOHERTY: It's just dreadful.
STEIN: So Doherty, who's 65, was thrilled when he found out that doctors were testing a new way to treat amyloidosis, using CRISPR, which allows scientists to make very precise changes in DNA.
DOHERTY: I thought, fantastic. I couldn't believe my luck.
STEIN: CRISPR has already started helping patients suffering from the blood disorders sickle cell disease and beta thalassemia. And doctors are trying to use it to treat cancer and restore vision to people blinded by a rare genetic disorder. But those experiments involve taking cells out of the body, editing them in the lab and infusing them back in, or injecting CRISPR directly into cells that need fixing. The study Doherty volunteered for is the first in which doctors are simply infusing the gene editor and letting it find its own way to the right gene in the right place - in this case, a gene in cells in the liver pumping out the destructive protein.
John Leonard is the CEO of Intellia Therapeutics, the company sponsoring the study.
JOHN LEONARD: This is the first example in which CRISPR-Cas9 is injected the into the bloodstream - in other words, systemic administration, where we use it as a way to reach a tissue that's far away from the site of injection and very specifically edit particular disease-causing genes.
STEIN: And it looks like it worked. Doctors infused billions of microscopic structures, known as nanoparticles, into Doherty and five other volunteers. Each nanoparticle carried the genetic code for the CRISPR gene editor. The nanoparticles made their way to the liver and unleashed an army of CRISPR gene editors, which honed in on the target gene to disable it. Within weeks, the levels of bad protein causing the disease plummeted.
JULIAN GILLMORE: It's amazing. It's - you know, it's phenomenal. It really is exciting.
STEIN: Dr. Julian Gillmore is leading the study at the University College London.
GILLMORE: This has the potential to completely revolutionize the outcome for these patients who have lived with this disease in their family for many generations. You know, it's decimated some families that I've been looking after. So, you know, this is amazing.
STEIN: The patients will have to be followed much longer, and many more patients will have to be treated, to make sure the treatment's as safe as it looks and to determine how much it's helping patients. But, Gillmore says, the approach could help those struck by a far more common version of the disease and provides the first good evidence that CRISPR could be used like this to treat many other, much more common diseases for which taking cells out of the body or directly injecting CRISPR isn't realistic, like heart disease, muscular dystrophy and maybe even brain disorders like Alzheimer's.
FYODOR URNOV: This is a wonderful day for the future of gene editing as a medicine.
STEIN: Fyodor Urnov is a professor of genetics at the University of California, Berkeley.
URNOV: What's striking about these new data is not merely the evidence of safety and efficacy but the avenues or highways it opens up for us in terms of traveling to new destinations in the world of genomic medicine.
STEIN: He says, it's a new world.
URNOV: We as a species are watching this remarkable new show called "Our Gene-Edited Future."
STEIN: For his part, Patrick Doherty is thrilled.
DOHERTY: I feel fantastic. I feel fantastic.
STEIN: He started feeling better within weeks of the treatment.
DOHERTY: I definitely notice an improvement in terms of my mobility, my heart, my moving about. I'm walking again. I do 15,000, 20,000 steps a day - weekend I go up again hill-walking with the dog.
STEIN: Doherty's looking forward to the future again.
DOHERTY: I'm really thankful for it - really thankful for it.
STEIN: And he hopes CRISPR will help some of his friends and relatives avoid the terrible fate his father, uncles and friends suffered.
Rob Stein, NPR News.
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