China is launching an initial human clinical trial using CRISPR in the treatment of lung cancer. The trial should start in August following approval by the hospital ethics board on 6 July. The protocol has been prepared over the last 18 months, under the direction of Lu You, an oncologist at Sichuan (Chengdu) University Hospital. Following the announcement of a similar type of trial in the United States at the beginning of the week (see CRISPR: A clinical trial focusing on somatic gene therapy is about to start in the United States), the Chinese team is said to be confident, but “cautious”.
Lung cancer patients will be injected with genetically modified immune cells (T lymphocytes, previously removed from these patients). The aim is to modify the gene coding the PD-1 protein in these cells – a protein that stops immune defence system cells from attacking healthy cells as well as tumours. Scientists are also considering a second gene and the introduction of a third.
However, CRISPR may trigger genetic modifications “in the wrong place in the genome” with potentially harmful consequences. Chengdu MedGenCell, a biotechnology company, is therefore responsible for checking and validating cells prior to injection. Scientists will also be vigilant because their approach could trigger an excessive auto-immune response in which the cells could attack the intestine or other normal tissues.
The phase I trial “has essentially been designed to check whether the approach is safe”. The team will examine the effects of three different dosage regimens on ten people and intends to proceed slowly, gradually increasing the dose with only one patient, who will be closely monitored for side effects. However, scientists will also monitor blood markers, which will indicate whether the treatment is working.
Nature, David Cyranoski (21/07/2016)