Chinese scientists are preparing to set a world’s first by treating lung cancer patients with immune cells modified using the CRISPR–Cas9 gene editing technique. The team of clinical researchers hopes the modified immune cells will attack the cancer cells, offering a treatment option in cases where other conventional treatments have failed. “This technique is of great promise in bringing benefits to patients, especially the cancer patients whom we treat every day,” said lead oncologist Lu You from Sichuan University’s West China Hospital in an article published recently in Nature.
Lu and his team plan to extract T-cells from cancer patients and modify them using the CRISPR–Cas9 technique. The technology will knock out the PD-1 gene, which sits on the surface of the T-Cell and prevents the cell from attacking healthy cells that have the companion PD-L1 protein. Many cancer cells also express this standard PD-L1 marker as a defensive mechanism to prevent the body’s T-cells from attacking them. By disabling this PD-1 gene and removing the PD-1 protein, the modified T-cell will be free to destroy the cancer cells.
These modified, cancer-killing T-cells will be multiplied in the lab and then injected into a patient’s bloodstream where they will then make their way through the body to the cancer cells. The first phase of this human trial is designed to test whether this approach is safe to use in humans. One primary concern is the overstimulation of the immune system due to these newly introduced modified T-cells, which could attack healthy cells in other body systems. The team plans to start with a small dose of the modified T-cells and then gradually increase the dosage in a single test patient. The treatment will be closely monitored by the researchers to ensure the treatment is working to remove the cancer cells and not harming the body’s healthy cells in the process.
Scientists in the United States are planning similar human clinical trials, but they are not expected to receive full approval for the technique until the end of 2016. A team of researchers from the University of Pennsylvania in Philadelphia already received approval from the US National Institutes of Health (NIH), but are still waiting for the green light from the US Food and Drug Administration (FDA) and a university review board before they begin their trials.