CRISPR Gene Editing Was Successfully Used To Kill Cancer Cells In Patients
- CRISPR is a revolutionary method of gene editing that allows researchers to easily alter DNA sequences and modify gene function
- The trial showed that immune responses are not a barrier in gene editing, a previous worry
- The cells were able to kill the cancer up to nine months after being edited
Given the excitement surrounding CRISPR, it’s worth nothing that the trial involved just three test subjects due, in part, to the safety precautions implemented.
Read More“In our case, we wanted to rewrite it so the gene would no longer function knocking it out,” he says. “We used three different guide molecules to find that location of where the different treated genes would be. And then we used the Cas9, which acts like molecular scissors. It cuts DNA on both strands at the site the guide tells them to cut it at.
“Out of 1,000 different cuts, on average we found only one in 1,000 was at the wrong site,” he continues, “so, it’s really high precision.”
The trial showed that immune responses to Cas9 are not a barrier in gene editing through CRISPR, a previous worry.
The cells were able to kill the cancer up to nine months after being edited. Researchers also found the cells could be successfully edited in three unique ways.
The first two edits in the trial allowed for cells to find and destroy tumors by removing and reprogramming a T cell’s natural receptors. The third edit took out the bodyguard, PD-1, which can block T cells from completing their tasks.
The approach used for this study is similar to that of CAR T-cell therapy, a technique pioneered by June in which immune cells are engineered to fight the cancer.
“It helped a lot because we knew how to do genetic engineering,” says June of his experience with CAR T-cell therapy. “One of the things that you do with CAR T-cell therapy is you use an engineered virus to modify the cells. In CAR cells you use the virus to insert the gene, or the CAR. In this case we used the engineered virus to insert a T-cell receptor. Because we had so much experience with that, it made it easier.”
In both cases the researchers started off by collecting T cells from patient’s blood. In this study, instead of arming cells against certain proteins, researchers used CRISPR editing to remove three genes.
Of the patients, the first had myeloma, Dr. June says, and she had eight lines of chemo therapy and three bone marrow transplants [prior to the study]. It was incredible what she had survived. It took us two years of working with the FDA and many review boards to get full approval.
“During that process they put many restrictions on the trial,” he continues. “We had actually screened 43 patients and then six of them enrolled. It was very difficult to get patients because of all this.”
The Future of CRISPR
Where will CRISPR give humans the capability to advance next? One indication came in November 2018 when a scientist out of Hong Kong announced that he had used CRISPR to edit the genomes of twin baby girls. This was the first recorded instance of the technology being used to customize genes for newborn babies.
Related: This Man's Tumor Suddenly Disappeared, and Doctors Are Trying to Figure Out Why
As for trials, June explains there’s now a green light to design trials that ask questions such as, “‘Does it actually have efficacy and kill tumors in patients?’ We saw some signs of that in our trial, but the trial was not designed to assess efficacy because we only gave one infusion and a single dose. Future trials will give more infusions and test higher doses.”
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