“We are trying to develop a last resort when everything else fails.” Says Lu You, oncologist and team leader at the West China Hospital affiliated with Sichuan University in Chengdu, China. His team, which is developing a method to infuse CRISPR/Cas9-edited T cells into patients with metastatic non-small cell lung cancer, received the green light from the hospital’s review board to start clinical trials in early July, according to a news report from Nature.
What’s the Plan and What Are the Concerns?
While the CRISPR/Cas9 gene-editing technique has been proven in many applications and organisms – from bacteria to the rhesus monkey, clinical trials in human patients have been a taboo for quite a few years due to various safety concerns namely the lack of an available “stop switch” mechanism in the general field of gene therapy. In this particular case, Lu You’s group, in cooperation with Chengdu MedGenCell, is planning to extract T cells, subject them to CRISPR/Cas9 gene editing to specifically knock out the PD-1 gene, and re-infuse the in vitro multiplied T cells back into the human patients. The PD-1 gene serves as the one of the many checkpoints that determine whether an immune response should be launched – both to defend against invading antigens and to prevent the accidental attack on healthy tissue.
The knockout of this PD-1 gene is expected to significantly increase the chance of eliciting an immune response in cancer patients. However, such an all-out response also raises concerns, as noted by Timothy Chan, a clinical researcher at Memorial Sloan Kettering Cancer Center in New York City. The excessive autoimmune response may cause the re-infused T cells to attack other targets in an unspecific pattern that involves healthy tissue. “All the T cells – everything will be active. That will be a concern,” says Chan.
No Speed Limit For Science: CRISPR Proceeds With Caution in China
Nevertheless, China already has a reputation as a fast-mover in the field of CRISPR/Cas9 applications. If the above-mentioned clinical trials proceed as planned, it will be the newest entry in a list of firsts for China in the CRISPR/Cas9 gene editing field. Such firsts – usually not without controversy – include the first CRISPR/Cas9 editing in primates and the first CRISPR/Cas9-edited human embryos. The latter attracted a lot of ethical controversy and the research manuscript was rejected by two prominent science journals, Nature and Science.
The US is also planning to start human trials on CRISPR/Cas9-edited T cells, but first needs to get approval from both the NIH and the FDA. So, trials are not expected to be issued before the end of 2016.
Is the Fast Track the Right Track?
In the current field of gene editing-based clinical trials, timing is a pivotal factor. China’s current fast-tracked approval process is a major incentive for researchers. Taking advantage of this fast-track approval process and being the first in the field not only enables a solid foot on patents and related legal affairs, but also guarantees substantial attention from public media, a more effective marketing approach than traditional advertising. Again, such a queue-jumping practice usually does not come without controversy, and potential investors will be carefully evaluating potential risks before getting on the “CRISPR bandwagon”.
Interested in learning more about emerging technologies?
Further Readings:
Chinese scientists to pioneer first human CRISPR trial. Nature News, 21 July 2016
First CRISPR clinical trial gets green light from US panel. Nature News, 22 June 2016
Image courtesy of pixabay.com
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