In sickle cell disease, abnormal hemoglobin causes blood cells to become hard and crescent-shaped. These misshapen cells clump together and block blood flow to organs, causing bouts of extreme pain. The cells then die prematurely, leading to a lack of healthy red blood cells and anemia.
Beta-thalassemia also causes anemia because the body produces less hemoglobin than normal.
People with life-threatening beta thalassemia require blood transfusions every 3 to 5 weeks and require other medications throughout their lives.
“Sickle cell disease and beta thalassemia are both painful, lifelong conditions that can be fatal in some cases,” said Julian Beech, interim executive director of healthcare quality and access at the UK’s MHRA. said Thursday.
Kasugebi is aimed at restoring the function of hemoglobin in the body. This treatment is not traditional medicine. Rather, it requires a complex procedure. The patient’s stem cells are collected from the bone marrow and sent to a laboratory for manufacturing. So scientists use Crispr to edit genes aimed at turning on functional hemoglobin.
The patient must then undergo conditioning treatments to prepare the bone marrow to accept the modified cells. You may then need to spend a month or more in the hospital while the edited cells colonize your bone marrow and begin making healthy red blood cells.
In the trial conducted by Vertex and Crispr Therapeutics, 45 patients were treated with Kasgevy, but only 29 were followed for at least 18 months. Of these, 28 of them remained free of severe pain attacks for at least 1 year after treatment.
In a study of patients with beta-thalassemia, 54 patients have received Kasugevy so far. Of the 42 patients who were followed for a sufficient period of time, 39 did not require blood transfusions for at least 1 year after treatment. In the remaining three of her patients, the need for blood transfusions was reduced by more than 70%. Side effects of treatment include nausea, fatigue, fever, and increased risk of infection. Both trials are ongoing.
Because Crispr is designed to permanently alter the genome, scientists believe its effects could last years, if not decades.
Currently, sickle cell disease can be cured with a bone marrow transplant from a compatible tissue donor, but only about 20 percent of patients receive a transplant. Transplants also have risks and may not work. This can lead to life-threatening complications in which the donor stem cells attack the recipient’s body.
Vertex and Crispr Therapeutics have not announced the price of this therapy, but it will likely be expensive. Vertex said it is working closely with U.S. national health authorities to ensure access for eligible patients as soon as possible.