First genome-editing trial in Europe gets go-ahead

Europe's first clinical trial to use genome editing in humans has received approval to start later this year.

CRISPR Therapeutics, headquartered in Zug, Switzerland, has got the regulatory go-ahead to test its therapy in patients with the inherited blood disorder, beta-thalassemia. So far, China has been the only country, which has used genome editing techniques to treat patients in clinical trials (see BioNews 935).

The biotechnology company applied for regulatory approval to test CTX001 in patients with beta-thalassemia and sickle cell disease in December last year.

'Beta-thalassemia is a devastating disease that requires serious and chronic medical intervention,' said Dr Tony Ho, head of research and development at CRISPR Therapeutics, at the time of that announcement. 'The efficient and precise editing in a patient's own blood cells using CRISPR provides the possibility of a one-time treatment for those suffering from beta-thalassemia and sickle cell disease.'

The therapy, developed by CRISPR Therapeutics in collaboration with Vertex Pharmaceuticals, works by extracting a patient's blood stem cells and then using genome editing to make them produce high levels of fetal haemoglobin in red blood cells. The cells are then transfused back into the same patient. By elevating the levels of this type of haemoglobin in a patient's blood, researchers hope to alleviate the need for blood transfusions in beta-thalassemia patients and avoid sickle cell crises in sickle cell patients.

The approved trial aims to test the safety and efficacy of the therapy in adult beta-thalassemia patients in Europe.

'Certainly, 2018 promises to be the big year for clinical trials using CRISPR based genome editing,' geneticist Dr Helen O'Neill, at University College London, told the Telegraph. 'Results presented by [CRISPR Therapeutics] at a haematology meeting showed that the method dramatically increased fetal hemoglobin in beta thalassemia patients' cells. The therapy successfully edited over 90 percent of blood stem cells removed from patients, which were re-transfused.'

Professor Robin Lovell-Badge, at the Francis Crick Institute in London, said: 'Assuming they do get going, we will look back and think that this is the real beginning of gene therapy.'