The first serious clinical trials in humans using CRISPR continue to wow, after follow-up findings three years post procedure demonstrate that all patients but two remain essentially cured of two blood disorders.
The treatment involved taking samples of the patients’ stem cells, and using CRISPR Cas-9 gene editing to enhance the levels of fetal hemoglobin, before reintroducing them back into patients.
Initial results were extremely promising, with the first two patients becoming essentially cured. The 18-month follow-up, as GNN reported, was even more exciting, with a dozen patients treated for sickle cell disease (SCD) and transfusion-dependent thalassemia (TDT) all showing no signs of either symptoms or serious side effects.
SCD can cause a variety of health problems including episodes of severe pain, called vaso-occlusive crises, as well as organ damage and strokes, while patients with TDT are dependent on blood transfusions from early childhood.
The only available cure for both diseases is a bone marrow transplant from a closely-related donor, an option that is not available for the vast majority of patients because of difficulty locating matched donors, the cost, and the risk of complications.
These new findings, presented at the European Hematology Association Congress, found that from 75 patients, just two remain uncured of their respective diseases, in this case TDT. However their transfusion requirements have both radically declined, estimated at 75% and 89% less than previous needs.
New Atlas reports that the U.S. Food and Drug Administration (FDA) has given this treatment, called “exa-cel,” a Fast Track designation.
The findings haven’t been peer-reviewed just yet, but the development company Vertex is hoping to submit exa-cel to the FDA for market approval by the end of the year.
It would be the first CRISPR treatment to land on American markets since the technology was developed.