PHOTO: BARBARA RIES FOR UCSF
There are key moments in the history of every disruptive technology that can make or break its public perception and acceptance. For CRISPR-based genome editing, such a moment occurred 1 year ago—an unsettling push into an era that will test how society decides to use this revolutionary technology.
In November 2018, at the Second International Summit on Human Genome Editing in Hong Kong, scientist He Jiankui announced that he had broken the basic medical mantra of “do no harm” by using CRISPR-Cas9 to edit the genomes of two human embryos in the hope of protecting the twin girls from HIV. His risky and medically unnecessary work stunned the world and defied prior calls by my colleagues and me, and by the U.S. National Academies of Sciences and of Medicine, for an effective moratorium on human germline editing. It was a shocking reminder of the scientific and ethical challenges raised by this powerful technology. Once the details of He’s work were revealed, it became clear that although human embryo editing is relatively easy to achieve, it is difficult to do well and with responsibility for lifelong health outcomes.
It is encouraging that scientists around the globe responded by opening a deeper public conversation about how to establish stronger safeguards and build a viable path toward transparency and responsible use of CRISPR technology. In the year since He’s announcement, some scientists have called for a global but temporary moratorium on heritable human genome editing. However, I believe that moratoria are no longer strong enough countermeasures and instead, stakeholders must engage in thoughtfully crafting regulations of the technology without stifling it. In this vein, the World Health Organization (WHO) is pushing government regulators to engage, lead, and act. In July, WHO issued a statement requesting that regulatory agencies in all countries disallow any human germline editing experiments in the clinic and in August, announced the first steps in establishing a registry for future such studies. These directives from a global health authority now make it difficult for anyone to claim that they did not know or were somehow operating within published guidelines. On the heels of WHO, an International Commission on the Clinical Use of Human Germline Genome Editing convened its first meeting to identify the scientific, medical, and ethical requirements to consider when assessing potential clinical applications of human germline genome editing. The U.S. National Academy of Medicine, the U.S. National Academy of Sciences, and the Royal Society of the United Kingdom lead this commission, with the participation of science and medical academies from around the world. Already this week, the commission held a follow-up meeting, reflecting the urgent nature of their mission.
Where is CRISPR technology headed? Since 2012, it has transformed basic research, drug development, diagnostics, agriculture, and synthetic biology. Future CRISPR-based discoveries will depend on increased knowledge of genomes and safe and effective methods of CRISPR delivery into cells. There needs to be more discussion about prioritizing where the technology will have the most impact as well as equitable, affordable access to its products. As for medical breakthroughs, clinical trials using CRISPR are already underway for patients with cancer, sickle cell disease, and eye diseases. These and many other future uses of genome editing will involve somatic changes in individuals, not heritable changes that are transmissible. But the rapidly advancing genome editing toolbox will soon make it possible to introduce virtually any change to any genome with precision, and the temptation to tinker with the human germ line is not going away.
The “CRISPR babies” saga should motivate active discussion and debate about human germline editing. With a new such study under consideration in Russia, appropriate regulation is urgently needed. Consequences for defying established restrictions should include, at a minimum, loss of funding and publication privileges. Ensuring responsible use of genome editing will enable CRISPR technology to improve the well-being of millions of people and fulfill its revolutionary potential.
↵* J.D. is a cofounder of Caribou Biosciences, Editas Medicine, Scribe Therapeutics, and Mammoth Biosciences; scientific advisory board member of Caribou Biosciences, Intellia Therapeutics, eFFECTOR Therapeutics, Scribe Therapeutics, Mammoth Biosciences, Synthego, and Inari; and director at Johnson & Johnson. Her lab has research projects sponsored by Biogen and Pfizer.