CRISPR/Cas9 technology reached another milestone with encouraging results in two recent trials of CTX001. An article in Pharmaceutical Technology carried an announcement by CRISPR Therapeutics and Vertex Pharmaceuticals about their Phase I/II studies which showed encouraging efficacy and safety results of the investigational gene-editing therapy.
Two patients with severe blood disorders (Hemoglobinopathy) participated in the trials. One of the patients had beta thalassemia, which is a blood disorder that reduces the production of hemoglobin. This patient was transfusion dependent prior to the trial.
The second patient had sickle cell disease which is a severe hereditary form of anemia.
The Creation of CTX001
The process begins by collecting progenitor cells (descendants of stem cells) and hematopoietic stem cells that develop into all types of blood cells. The cells are collected from the peripheral blood of each patient.
Using the CRISPR/Cas9 technology, the cells are edited to create CTX001. Then the patient is re-infused with the edited cells by way of a stem cell transplant along with a conditioning regime that was administered prior to the transplant.
The stated goal of CRISPR and Vertex is to develop fetal hemoglobin in red blood cells. Fetal hemoglobin is the main oxygen transport protein found in the fetus. The focus is on the underlying genetic origin of these blood disorders. The intent is to reduce reliance on transfusions needed for sickle cell disease and beta thalassemia.
The patient with thalassemia had undergone sixteen transfusions a year prior to the trial. He has been transfusion-independent in the nine months since being treated with CTX001.
The patient with the sickle cell disease had been treated with CTX001 during the CLIMB-SCD-121 study about five months ago. This patient had experienced seven sickle cell crises within two years. These crises are common in sickle cell disease. The severe pain if persistent can cause organ damage. There have been no further crises since trial.
Representatives of Vertex and CRISPR agree that the data recently announced are “remarkable’ and show that CTX001 may be curative for beta thalassemia and sickle cell disease through CRISPR/Cas9-based gene-editing intervention.
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