Gene therapy for sickle cell disease steps closer

Researchers have found a way to repair the faulty gene that causes sickle cell disease, which they suggest is a significant step forward in the search for a viable gene therapy.

Scientists are seeing promising early results from the first studies testing gene editing for painful, inherited blood disorders that plague millions worldwide, especially Black people.

Doctors hope the one-time treatment, which involves permanently altering DNA in blood cells with a tool called CRISPR, may treat and possibly cure sickle cell disease and beta thalassemia.

Partial results were presented Saturday at an American Society of Hematology conference and some were published by the New England Journal of Medicine.

In sickle cell, defective hemoglobin leads to deformed, crescent-shaped blood cells that don’t carry oxygen well. They can stick together and clog small vessels, causing pain, organ damage and strokes.

Those with beta thalassemia don’t have enough normal hemoglobin, and suffer anemia, fatigue, shortness of breath and other symptoms. Severe cases require transfusions every two to five weeks.

The treatment studied attacks the problem at its genetic roots.

Doctors described 10 patients who are at least several months removed from their treatment. All no longer need regular blood transfusions and are free from pain crises that plagued their lives before.

In the womb, fetuses make a special type of hemoglobin. After birth, when babies breathe on their own, a gene is activated that instructs cells to switch and make an adult form of hemoglobin instead. The adult hemoglobin is what’s defective in people with one of these diseases. The CRISPR editing aims to cut out the switching gene. The treatment involves removing stem cells from the patient’s blood, then using CRISPR in a lab to knock out the switching gene. Patients are given strong medicines to kill off their other, flawed blood-producing cells. Then they are given back their own lab-altered stem cells.