(Picture: gopixa / Shutterstock.com)
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Researchers at the University of Pennsylvannia have opened a new chapter in the treatment of diseases and have gathered initial evidence for the safety of therapy against blood and connective tissue cancer in a small feasibility study.
Three people with advanced cancer were injected with immune cells that had been modified using the CRISPR gene editing technique without serious side effects. It is the first US clinical pilot study on this technique and the first CRISPR cancer study, the results of which have been published.
The aim of the researchers was first to check whether the technology can be used safely and not to find a cure. All three patients over the age of 60, two with a blood cancer called “multiple myeloma” and one with a sarcoma, ie connective tissue cancer, had treatment-resistant tumors that produced the same protein.
Dramatic effectiveness
Experimental research at the University of Pennsylvania started last April. The doctors took blood samples from the patients and genetically modified the immune cells they contained. More specifically, they inserted a gene to target the T cells against the cancer cells. Using the CRISPR procedure, they also deleted a gene called PD-1, which can slow down the immune system. PD-1 inhibitors have shown dramatic effectiveness in immunotherapy for some cancers. It is now a matter of incorporating the same ability directly into the DNA of T cells.
Each patient received a dose of their own T cells, which were changed using CRISPR. Nine months later, the modified immune cells were still in their blood. The results of the study were published in the journal “Science”.
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(Image: Text: Inge Wünnenberg; Graphics: Brian Sipple)
The scientists’ approach was not without risk. For example, they were concerned that the altered cells could trigger a problematic immune response because the protein used in the CRISPR process was derived from bacteria. Fortunately, that turned out to be unfounded.
Long-term effects
A second concern was that CRISPR gene processing can also produce so-called off-target effects, i.e. an effect in completely different places in the genome than the planned one. Theoretically, unintentional genetic deletions (deletions) can cause the cells to degenerate and the patient to develop cancer. The researchers observed some off-target changes, but no problematic ones.
Read more about the CRISPR gene editing method:
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However, the effectiveness of the treatment was limited. Although the patient’s condition stabilized during treatment and their tumors shrank, T cell injection had no long-term effects. A subject has already died. The other two have seen their cancer worsening and are now being treated differently.
The study will not be continued because the technology variant used is now out of date and gene editing technology has developed rapidly since 2016 when the study was approved. However, the encouraging results should pave the way for further patient testing using gene editing technologies. For example, this year in Europe, the first patient with an inherited disease – beta thalassemia – was treated with a CRISPR procedure. Fyodor Urnov of the University of California at Berkeley, who was not part of the University of Pennsylvania pilot study, told Science that the study “answered questions that have long troubled the field.”
(Charlotte Jee, Antonio Regalado)
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