A New Treatment Cures an Old Disease—and Possibly Many Others

Casgevy is the world’s first government-approved, effective gene-edited cell therapy to treat sickle-cell disease.


For some professionals—advertising executives, sports broadcasters, cult leaders—the word “miracle” comes with the territory. But when a doctor or a researcher uses it, you know something big is going on. Such is the case with the recent announcement of Casgevy, the world’s first government-approved, effective gene-edited cell therapy to treat sickle-cell disease, a genetic mutation in which red blood cells become rigid and crescent-shaped, making them tend to clog and block arteries and veins.

The way it works is simple in concept, if incredible in execution: doctors extract blood-forming stem cells from a patient’s circulating blood, then use a CRISPR-Cas9 gene-editing technique to edit a part of the genome that can lead to the production of functional red blood cells. The edited cells are then reinfused back into the patient, where they allow for the production of new, healthy red blood cells that exhibit their usual doughnut shape. It’s not entirely accurate to call such treatment a cure—more like a correction, in which a distortion within the body is amended, replaced, and erased from its genetic memory.

Whatever you call it, it seems to eliminate the excruciating pain, kidney failure, bone necrosis, and strokes that often afflict sufferers of the disease. While patients will be followed for 15 years to confirm whether the fix lasts, it’s off to a good start: of the 30 patients in the treatment’s trial study, only one reported a blockage-induced pain episode within a year after initial treatment.



While the world’s seven million or so sickle-cell sufferers are surely cheering the loudest at such news, there’s plenty of reason why the rest of us should rise up and applaud. For Casgevy is more than a treatment: it is a kind of gateway, a passage toward an entirely different future. Granted, the technology is far from perfect: today’s gene editors can lead to unfavourable mutations and off-target effects on other genes. And the extreme cost (the price tag for Casgevy is $2.2 million (U.S.) per treatment), they are far too expensive to use across an entire population. But given enough time, further research, more engineering refinement—well, anything is possible.

Today, we have to live with genetic disorders that debilitate our lives: diabetes, cystic fibrosis, muscular dystrophy. Tomorrow, we may be able to make many of them functionally obsolete. If that’s not a miracle, it’s hard to say what is.