For a lucky few, like Kendric, the treatment could make possible lives they have longed for. A solemn and shy adolescent, he had learned that ordinary activities — riding a bike, going outside on a cold day, playing soccer — could bring on episodes of searing pain.

“Sickle cell always steals my dreams and interrupts all the things I want to do,” he said. Now he feels as if he has a chance for a normal life.

The key thing is that this class of treatment is a cure. Once done with treatment, the expectation is that he’ll produce enough normal hemoglobin to live normally.