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CRISPR gene-editing treatment shows success in first human patients

A CRISPR fix for two blood disorders shows promising early results.

An investigational therapy using the revolutionary gene-editing technology CRISPR has shown promising initial results in two patients suffering from inherited blood diseases. The treatment, dubbed CTX001 and developed by CRISPR Therapeutics and Vertex, utilize CRISPR to edit human stem cells. Preliminary results, discussed on Tuesday, suggest the therapy is safe and pave the way for further clinical trials of the new treatment.

The two patients suffer from different hemoglobinopathies: disorders which affect hemoglobin, the protein that carries oxygen around the body. One patient, based in the US, suffers from sickle cell disease, which produces misshapen, sickle-shaped red blood cells. The patient first began receiving the CRISPR fix in April this year. The second, based in Europe, suffers from beta thalassemia, a disease with a dramatic reduction in hemoglobin production, and has been on the treatment for nine months.

In sickle cell disease, patients suffer painful "crises" as the sickle-shaped blood cells clog up blood vessels, while patients with beta thalassemia require constant blood transfusions to manage their hemoglobin levels. 

The experimental treatment left patient one free of painful crises and patient two without the need for transfusions.

"We are very encouraged by these preliminary data, the first such data to be reported for patients with beta thalassemia and sickle cell disease treated with our CRISPR edited autologous hematopoietic stem cell candidate, CTX001," Samarth Kulkarni, CEO of CRISPR Therapeutics, said in a press release Tuesday.

The treatments aren't easy or cheap. They require teams of health care professionals to collect stem cells from a patient's blood before they are edited, outside of the body, with CRISPR. The gene-editing tech "turns on" a version of the hemoglobin gene normally deactivated in adulthood and the patients undergo a stem cell transplant to receive the edited genes. Once the cells are returned to the patient, it's hoped they set up shop in the bone marrow and begin to pump out hemoglobin in adequate amounts.

CRISPR Therapeutics and Vertex will look to enroll up to 45 patients from across the US, Canada and Europe in trials of CTX001, with each patient receiving long-term follow-up study to assess safety of the treatment. 

CRISPR has made headlines over the last year as scientists grapple with the moral and ethical considerations of being able to efficiently edit human DNA. In November 2018, Chinese scientist He Jiankui revealed he had edited human embryos with CRISPR, creating a pair of gene-edited twins. The conduct was slammed by the wider scientific community, including some of CRISPR's inventors, and calls for a global moratorium on human genome editing have slowly gathered steam throughout 2019

But CRISPR has also been floated as a technology to bring back the woolly mammoth or eradicate entire species of malaria-carrying mosquitoes. As scientists and ethicists wrestle with the considerations, researchers are putting their heads together to come up with even more impressive, breakthrough technologies to accurately manipulate DNA. With therapies like CTX001 showing promise, a new era of gene therapy is upon us.




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