CRISPR Therapeutics, Vertex start first company-backed human CRISPR trial

While research groups in China have already started testing CRISPR in humans, CRISPR Therapeutics and Vertex Pharmaceuticals are the first companies to sponsor a human trial of the gene editing technology. The trial will take place at a single site in Germany and will test a gene therapy in patients with beta thalassemia.

Vertex licensed CTX001, an autologous gene-edited hematopoietic stem cell therapy, from CRISPR in December. It was the first CRISPR-based treatment to come out of a four-year, $105 million deal the pair struck in 2015. At the time, Vertex paid up $75 million in cash and took a $30 million stake in CRISPR Therapeutics in exchange for the right to license up to six gene-editing programs. CTX001 is being developed for the blood disorders sickle cell disease and beta thalassemia.

Both disorders are caused by mutations in the beta-globin gene, which codes for a part of hemoglobin, the oxygen-carrying component of red blood cells. This results in missing or defective hemoglobin. CTX001 was developed on the knowledge that fetal hemoglobin—found in newborn babies but later replaced by adult hemoglobin—can be protective in adults who have blood disorders.

CTX001 uses CRISPR gene-editing ex vivo—that is, outside the body. A patient’s cells are harvested and edited to increase fetal hemoglobin levels in the patient’s blood cells. The edited cells are then infused back into the patient where they are expected to produce blood cells with fetal hemoglobin and compensate for defective adult hemoglobin.

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The new trial will test CTX001 in up to 12 adult patients who have transfusion-dependent beta thalassemia, according to an announcement on It will take place at a single hospital in Regensburg, Germany.

“CRISPR Therapeutics and Vertex are advancing CTX001 as the first gene editing treatment for both sickle cell disease and beta thalassemia using the CRISPR/Cas9 technology, and have now opened the beta thalassemia study for enrollment in a Phase 1/2 trial in Europe,” said a CRISPR Therapeutics spokesperson via email. “This is one important step of many toward bringing the promise of this new technology to patients with serious diseases like SCD and beta thalassemia, and we are thrilled to be at the forefront of what we believe may be a fundamental change in the treatment of disease.”

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The partners have been planning a U.S. trial testing the treatment in sickle cell disease, but its IND ran into an FDA clinical hold in May. Details were few and far between and shares in CRISPR slipped 15% at the time.

For a time, it looked like Editas Medicine would be the first to launch a human trial, with plans to start testing a CRISPR treatment for a rare form of blindness in 2017. Manufacturing issues delayed the timeline to 2018, with CEO Katrine Bosley saying in the company’s second-quarter update that the IND filing is slated for October.