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Ever since its discovery in 2012, the CRISPR/Cas9 gene-editing system has promised to "revolutionize" modern medicine and transform the lives of patients suffering from incurable genetic diseases. The world has waited patiently for it to deliver on such promise. However, this wait has been necessary to ensure that CRISPR therapies are safe. Behind the scenes, scientists have worked extensively to ensure that CRISPR technology can be delivered to humans without dangerous off-target effects on the genome.



In January of this year, CRISPR Therapeutics and Vertex Pharmaceuticals announced that the U.S. Food and Drug Administration (FDA) had granted fast track designation for an investigational, autologous, gene-edited hematopoietic stem cell therapy for patients suffering from hemoglobinopathies. The therapy is known as CTX001. Now, the companies have announced positive safety and efficacy interim data from the first two patients with severe hemoglobinopathies treated with the CRISPR/Cas9 gene-editing therapy CTX001 in ongoing Phase 1/2 clinical trials.



The enrolled patients suffer with two different hemoglobinopathies: transfusion-dependent beta thalassemia (TDT) and sickle cell disease (SCD).





What is transfusion-dependent beta thalassemia?



Beta thalassemia is a genetic blood disorder, characterized by either reduced or no production of β-globin, a component of hemoglobin, the oxygen-carrying protein. Beta thalassemia is a result of mutations in the beta-globin (HBB) gene, and severity of the disorder is dependent on whether an individual carries a mutation in one HBB gene, or both. Patients with the most severe forms of beta thalassemia, TDT, experience severe anemia, and unfortunately have to rely on red blood cell transfusions throughout their lives, which can have iron toxicity implications.



The TDT patient received CTX001 in early 2019, and so the data announced represents nine months of safety and efficacy follow-up.





What is sickle cell disease?

CRISPR/Cas9 as a therapeutic







Video credit: TED.





What is CTX001?

Interim results from the TDT and SCD patients

Forward-thinking in CRISPR gene-editing therapy

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