Some say a global moratorium on germline gene editing is called for in the wake of He Jiankui’s controversial study.

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Organizers of gene-editing meeting blast Chinese study but call for ‘pathway’ to human trials

HONG KONG, CHINA—An international conference on human gene editing dominated by news of the birth of the world's first genetically engineered babies concluded today with a statement from the organizers that harshly condemned the controversial study. But it did not call for a global moratorium on similar studies, as some scientists had hoped; instead it called for a "translational pathway" that might eventually bring the ethically fraught technology to patients in a responsible way.

The hotly debated study, which apparently resulted in twin baby girls whose genomes were altered in a way that could affect their offspring, came to light on the eve of the second International Summit on Human Genome Editing here. The first summit, held in Washington, D.C., in December 2015, concluded with a statement that specifically said that unless and until safety, efficacy, and ethical and regulatory issues are resolved, "it would be irresponsible to proceed with any clinical use of germline editing," a reference to genetic modifications that can be passed on to the next generation.

But that is exactly what Chinese researcher He Jiankui did, crippling a gene known as CCR5 in hopes of making the babies, as well as their offspring, resistant to HIV infection. After the news was reported, He appeared yesterday at a special session at the summit to defend his work and answer questions from the stunned audience. (He, an associate professor at the Southern University of Science and Technology in nearby Shenzhen, China, withdrew from a second session on embryo editing scheduled for Thursday afternoon.)

Scientists and ethicists have almost universally condemned He's work as premature, irresponsible, and unjustified in exposing the girls to long-term risks associated with gene editing for little, if any, medical benefit. A few take a more nuanced view; Harvard University geneticist George Church told Science he feels an "obligation to be balanced" and called the international reaction "extreme."

Prior to the summit, the 14 organizers were undecided about compiling a new statement just 3 years after the last one. But after news of He's study triggered an international outcry. "We had to" issue a new statement, says Jennifer Doudna of the University of California, Berkeley, a CRISPR pioneer and member of the organizing committee. The group's chair, David Baltimore of the California Institute of Technology in Pasadena, read the text to the audience today.

Progress over the last 3 years and the discussions at the current summit … suggest that it is time to define a rigorous, responsible translational pathway toward [clinical] trials.

Organizers of the second International Summit on Human Genome Editing

Without mentioning He by name, the statement refers to "an unexpected and deeply disturbing claim that human embryos had been edited and implanted, resulting in a pregnancy and the birth of twins." The procedure was "irresponsible and failed to conform with international norms," the organizers say; its alleged flaws include inadequate medical justification, a poorly designed protocol, a failure to protect the welfare of the babies, and a lack of transparency at all stages of the study. The authors recommended an independent assessment to verify that He's claimed DNA modifications were actually made.

The committee reiterated its position that it's too early for any clinical use of germline editing. But, it said, "Progress over the last 3 years and the discussions at the current summit … suggest that it is time to define a rigorous, responsible translational pathway toward [clinical] trials. Such a pathway will require establishing standards for preclinical evidence and accuracy of gene modification, assessment of competency for practitioners of clinical trials, enforceable standards of professional behavior, and strong partnerships with patients and patient advocacy groups."

Some had hoped for a call to ban human trials for the time being. "Given the current early state of genome editing technology, I'm in favor of a moratorium on implantation of edited embryos … until we have come up with a thoughtful set of safety requirements first," CRISPR pioneer Feng Zhang of the Broad Institute in Cambridge, Massachusetts, said in a statement issued on 26 November. A petition circulated online since yesterday and emailed to the committee and journalists urged the group to "call on governments and the United Nations (UN) to establish enforceable moratoria prohibiting reproductive experiments with human genetic engineering." The petition, organized by the Center for Genetics and Society in Berkeley and Human Genetics Alert in London, had drawn the support of 11 organizations and more than 100 individuals earlier today.

"We don't believe anymore that the scientific community can self-regulate," Jaydee Hanson of the International Center for Technology Assessment in Washington, D.C., said today. If scientists won’t get behind a call for U.N. action, Hanson warned, his and other groups will issue one on their own.

The question of self-regulation came up several times during the meeting. As today's session drew to a close, Baltimore noted how difficult it is for the scientific community—or anyone—to restrain rogue scientists. He's research "has proven that if you want to be surreptitious in using this technology you can go a surprisingly long way,” he said.

The organizers announced that the next summit will be held in London, probably in 2021.