China has taken the lead in the use of CRISPR gene editing on humans. There are nine registered clinical trials in China that aim to treat several different cancers and HIV, but the stricter regulatory environment in Europe and the United States has prevented the new gene editing tool from being used to treat diseases in humans. There is only one registered clinical trial in the U.S, and none so far in Europe.
However, the wait is almost over. The first European clinical trial using CRISPR to treat human diseases has been approved and will start this year, although the location for the trial has not yet been announced.
What is known is the first disease to be treated with CRISPR technology in Europe will be beta thalassaemia – A common blood disorder that that results in severe anaemia due to reduced levels of haemoglobin. Patients with the condition have limited ability to transport oxygen around the body leading to oxygen shortages.
The disease is hereditary and is caused by genetic mutations. While the condition can be treated and managed, it usually requires a lifetime of treatment. The alternative is a bone marrow transplant or stem cell therapy, both of which carry risks.
However, CRISPR potentially offers a solution. If the gene responsible for beta thalassaemia can be altered, it is possible that the disease could be cured with a single treatment.
In the beta thalassaemia CRISPR trial, hematopoietic stem cells will be harvested from patients, the BCL11A gene will altered using CRISPR, and the genetically engineered stem cells will be reintroduced into the patients. The aim is to increase fetal haemoglobin levels to normal levels. If successful, this will be a one-time treatment that could cure the disease.
The beta thalassaemia CRISPR trial has been approved by regulators in the United Kingdom, and the trial will be conducted by CRISPR Therapeutics. The aim of the first part of the trial is to assess safety and efficacy of the treatment in humans.