At least 86 people have been treated with the CRISPR genome-editing method in China since 2015. We know this thanks to , who spoke with many of the people carrying out these first trials.
The WSJ says this means China is racing ahead in gene editing, while the US is being left behind. But this is rather misleading.
For starters, the first-ever use of gene editing to treat people was in the US, in 2009. Immune cells were removed from people with HIV, edited outside the body to disable the gene that the virus exploits to infect cells, then returned to the body. These trials continue.
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The first-ever use of gene editing to change cells inside the body was also in the US. In November 2017, intended to give his liver the ability to make a key enzyme.
The first-ever use of gene editing to cure cancer, meanwhile, was in 2015, in the UK. A 1-year-old girl called Layla, who was dying of leukaemia, was injected with immune cells modified in several ways, including using gene editing to disable one gene. She is still cancer free.
So, far from lagging behind, the US and the UK can lay claim to most of the big firsts in gene editing. True, these trials involve older editing methods, known as ZFN and TALEN, rather than CRISPR. But the method doesn鈥檛 really matter as long as it is safe and effective.
Simplistic method
Secondly, almost all the CRISPR trials in China involve a simple approach: disabling a single gene in immune cells called PD-1. This stops the cells attacking the body and is often exploited by tumours to thwart immune attacks.
Based on what we know about drugs that block PD-1, disabling it is unlikely to be a miracle cure on its own. There is also a risk that the edited cells will attack normal, healthy tissues. With the PD-1 off-switch disabled, there would be no way to stop this.
The first CRISPR trial likely to go ahead in the US is more sophisticated. The plan is to disable several genes, including PD-1. An extra gene will also be added to make the immune cells target only cancer cells.
The researchers in China say some patients have shown signs of improvement, with their cancers shrinking. But at least 16 of the 86 treated have died. These deaths are being attributed to the cancers rather than the treatment, but it isn鈥檛 clear what, if anything, has been done to establish this.
The danger of rushing ahead with trials is that if they aren鈥檛 carefully designed and rigorously assessed, they may give misleading results. Take the rush to be the first to edit human embryos using CRISPR. The first few studies to be published 鈥� by teams in China 鈥� got enormous attention, but they were all deeply flawed because, for instance, they used abnormal embryos. So they didn鈥檛 tell us much that was useful. In fact, even the largest study yet published, by a team in the US, appears to be seriously flawed as well.
So, while researchers in the US may want to portray this situation as a race that their nation is losing, in order to spur regulators and funders into action, this is neither accurate nor helpful in the long run.
There is still a tremendously long way to go before we can turn CRISPR into an affordable treatment that can be widely used, and we鈥檙e only going to get there with rigorous trials and international cooperation, not a mad dash to be the first. If there is a race, it is one the tortoise will win.
