Doctors who had the first go at testing CRISPR gene editing technology on three cancer patients in the U.S. reported Wednesday that the technique seems safe and feasible.
The researchers first extracted some of the patients’ T cells, which help the body’s immune response. They changed the cells to improve their cancer-fighting ability, then injected the T cells back into the patients.
“The first step in this research is to show that CRISPR technology and gene editing in human cells is safe. The experience from the first three patients suggests the technology is indeed safe, but this certainly needs to be extended further,” said Howard Chang, one of the researchers and a professor of cancer genomics at Stanford University.
Two of the patients have multiple myeloma, a cancer that affects white blood cells. One patient has sarcoma, a cancer that forms in bones and connective tissues. Numerous standard treatments had failed for them.
Using CRISPR technology, the research team altered three genes that might have hindered the T cells’ ability to combat cancer. The altered cells should multiply in the body and act as a living drug to fight the disease.
Two months later, one patient’s cancer continued to progress while another patient was stable. It is too early to evaluate the third patient who was treated.
The researchers plan to test gene editing on 15 other patients to assess its safety and impact.
“The big picture implication for this research is that we can program a patient’s immune system to fight cancer. We still have a lot to learn about which cells and which genes to edit to get the best result,” Dr. Chang said. “But in the fullness of time, creating custom cells to fight disease may be feasible. Many cancer patients may have battered immune systems that have limited capacity to fight cancer. CRISPR technology may offer a new strategy to teach cancer patient’s own body to eliminate their cancer.”
Scientists in China reportedly have tried to treat cancer patients with CRISPR but have released little information about their work, according to NPR. This is the first study outside of China to make the same attempt.
The early results of the U.S. study were published by the American Society of Hematology. More details about the study will be shared at the society’s conference in December.
For the study, the researchers, primarily from the University of Pennsylvania, strived to change DNA outside a person’s body and return to the patients altered cells that are better equipped to combat cancer.
“The potential of T cell-based therapies to cure some cancer patients has been demonstrated. CRISPR technology and other gene editing approaches are important advances in further developing this class of immunotherapy and advancing these therapies to more types of cancers including solid tumors,” said Theresa Lavallee, vice president of translational medicine and regulatory affairs at the Parker Institute for Cancer Immunotherapy. She was not involved in the study.
By editing DNA outside a person’s body, doctors can avoid altering unintended tissue and cells, which Dr. Chang described as a “safer approach and appropriate for the first step of gene editing in humans.”
Gene editing permanently alters DNA to target the causes of a disease. CRISPR is a gene editing tool that was adapted from a naturally occurring genome editing system in bacteria.
The bacteria capture bits of DNA from an invading virus and then create genetic segments known as CRISPR arrays, which allow the bacteria to “remember” the virus. If the virus attacks again, the bacteria produce genetic pieces from the arrays to target and cut apart the virus’ DNA.
• This article is based in part on wire service reports.