Pushing cells against cancer
A proposal for the first clinical trial involving CRISPR-Cas9 gene editing has been approved by the National Institutes of Health Recombinant DNA Advisory Committee. The Phase I trial, which will require approval from the Food and Drug Administration, is designed to test the safety of using CRISPR gene editing to modify a persons own immune cells to target certain cancers.
Helping T cells
Dr. April Pyle, Associate Professor, Department of Microbiology, Immunology and Molecular Genetics, Member, Broad Stem Cell Research Center, University of California, Los Angeles:
Expertise: basic and translational human pluripotent stem cell biology; stem cell based therapeutic approaches for patients with muscular dystrophy.
“This is a very exciting development from a well-established team of scientists with a proven track record in engineered T cells for tumor targeting and they plan to extend their existing work to initiate an improved method to target cancer using engineered T cells after CRISPR gene editing.
“This trial will significantly advance our understanding of the utility and safety of CRISPR in human clinical trials and the importance of targeting multiple genes that could improve T cell mediated tumor targeting in multiple cancers.
“There are concerns with regard to potential off targets. However the team plans to evaluate this in multiple approaches including in-depth sequencing and long term culture to detect any potential transformations.
“When this therapy could get to the clinic depends on multiple variables; it could take several years to determine the safety and efficacy of this targeting platform and T cell function in vitro and in vivo. Questions remain including but not limited to what will be the efficiency (and off target effects) of targeting multiple genes using CRISPR and the need to evaluate off targets from all the guide RNAs proposed in the study.”
Dr. David Schaffer, Professor, Chemical and Biomolecular Engineering, Bioengineering, Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkley:
Expertise: neuroscience, biomolecular engineering, bioengineering, stem cell biology, gene therapy
“This ambitious approach fully harnesses the potential of CRISPR/Cas9 to target multiple genes in order to generate an anti-cancer T cell. Efforts with prior technologies have primarily targeted one gene.
“T Cell Receptor (TCR) therapies, which engineer a patient’s immune cells to attack a tumor, are extremely promising. This CRISPR/Cas9 approach would develop modified T cells using a new method that could potentially result in a more potent version of the therapy.
“I do not have all the details on how the researchers plan to monitor off target effects, but in general off-target is a risk for genome editing approaches. However, for late stage cancer patients, the risk may be outweighed by the potential benefit.
“Genome editing technologies have been progressively advancing in the clinic, and this first proposed therapeutic use of the CRISPR-Cas9 system is a landmark that could lead to safer and more efficacious cancer treatments.”