CRISPR Cancer Trial Success Paves the Way For Personalized Treatments
The approach was tested in 16 people with solid tumours, including in the breast and colon. "It is probably the most complicated therapy ever attempted in the clinic," says study co-author Antoni Ribas, a cancer researcher and physician at the University of California, Los Angeles. "We're trying to make an army out of a patient's own T cells." The results were published in Nature and presented at the Society for Immunotherapy of Cancer meeting in Boston, Massachusetts on 10 November.
Ribas and his colleagues began by sequencing DNA from blood samples and tumour biopsies, to look for mutations that are found in the tumour but not in the blood. This had to be done for each person in the trial. "The mutations are different in every cancer," says Ribas. "And although there are some shared mutations, they are the minority." The researchers then used algorithms to predict which of the mutations were likely to be capable of provoking a response from T cells, a type of white blood cell that patrols the body looking for errant cells. "If [T cells] see something that looks not normal, they kill it," says Stephanie Mandl, chief scientific officer at PACT Pharma in South San Francisco, California, and a lead author on the study. "But in the patients we see in the clinic with cancer, at some point the immune system kind of lost the battle and the tumour grew." After a series of analyses to confirm their findings, validate their predictions and design proteins called T-cell receptors that are capable of recognizing the tumour mutations, the researchers took blood samples from each participant and used CRISPR genome editing to insert the receptors into their T cells.
