In the US, approval was granted last month for the use of the revolutionary gene editing technique CRISPR in humans by the end of the year. But things have been moving a lot quicker on the other side of the Pacific, as Chinese scientists are now on the verge of being the first in the world to start trials, with plans already in motion to start them within a few weeks, Nature reports.
The experiment aims to use immune cells modified using CRISPR to treat patients with lung cancer where all previous conventional therapies have failed. They will use it to knock out a specific gene in the T-cells of the patients, multiply the cells in the lab, and then re-introduce them back. The hope is that the newly modified cells will circulate the body, hunting down and eventually destroying the cancer cells when they are found.
The trial is not really designed to see if they can cure the cancer, but more to check the safety of the procedure. They will test different dosages of the treatment, and proceed very slowly, starting with one patient and then slowly upping the dosage while closely monitoring the effects, before expanding it to 30 patients.
And the trial is fairly similar to the one that has been given the green light stateside. Both aim to knock out a particular gene known as PD-1, which is involved with the immune response, normally preventing it from attacking healthy cells, and something that the cancer in effect hides behind. The US Food and Drugs Administration has already given the go ahead for two other drugs that use antibodies to block PD-1, so that aspect of the trial is not that controversial.
The main issue is the overall safety of using CRISPR on humans. Mistakes are known to happen while using the techniques, with it targeting the wrong gene for example, although the researchers are confident that fail-safes are in place to prevent this. There is also the issue of whether or not the edited T-cells will be too general in their attack, not only eliminating the metastatic non-small cell lung cancer at which it is aimed, but also hitting healthy tissue such as the gut or adrenaline glands.
Some have argued that perhaps the trial should be using immune cells taken directly from the tumors, so that they are already in effect primed to attack the cancer, but the researchers have said that due to the positioning of the tumors in the lungs, this would be too difficult. They have also said that they are reassured by other experiments that have been approved by the FDA that have shown that the threat on healthy tissue is not too high.