Gene editing shows promise in sickle-cell disease

New treatments for sickle cell disease, including gene editing, are in the works after a decades-long lull in drug development for the condition primarily affecting African Americans. Several companies are exploring experimental therapies, with the New England Journal of Medicine recently reporting promising results from two clinical trials. In one study, researchers at Boston Children’s Hospital found that six patients who were treated with a novel gene therapy and followed for up to 29 months suffered fewer or none of the severe flare-ups that characterize the inherited disease, which is a type of anemia. In a study from Crispr Therapeutics and Vertex Pharmaceuticals, meanwhile, results showed that a patient with sickle cell who averaged seven severe pain crises annually did not have any in more than 16 months after receiving edited cells. The treatment pathway in both cases involves stimulating the production of fetal hemoglobin, which is not affected by the sickle-cell mutation. While the body typically stops producing it soon after birth, some people with sickle cell disease have a gene variant that lets them continue to make fetal hemoglobin. These individuals tend to have milder disease or be asymptomatic. Some of the novel therapies attempt to mimic this effect, but they also entail chemotherapy and bone-marrow transplants. While the new developments are promising for a population that currently has limited options, they also raise the question of the steep cost of the medical technology behind the treatments that could make them unaffordable or inaccessible to patients.