The research, reported on 18 March in Nature1, adds new safety features to an emerging class of cancer treatments known as chimeric antigen receptor (CAR)-T-cell therapies that are produced in the body. The development could lead to treatments that are cheaper to make and easier to administer than are those currently used against some blood cancers. At present, CAR-T therapies are made from a person's own T cells ' a type of immune cell ' which are isolated, engineered to express a synthetic protein known as a CAR and then reinjected into the body. Reprogramming T cells directly in the body would take less time, but it adds safety concerns, says Justin Eyquem, an immunologist at the University of California, San Francisco, and lead author of the study. For one thing, 'you don't want to edit other cells', he says. 'So we added multiple layers of safety.' CARs are designed to target cancer cells, allowing the engineered T cells to find and destroy tumours ' an approach that has produced dramatic remissions in some people with cancers of the blood, such as leukaemia or lymphoma....

But within months, KJ's name ' and megawatt, chubby-cheeked smile ' would be splashed across newspapers and broadcasts around the world as the first known person to receive a personalized CRISPR-based genome-editing therapy. Soon after KJ was born in August 2024, doctors noticed that he was sleeping too much and eating too little. After a bevy of tests, they found that KJ has an ultra-rare genetic condition, called carbamoyl-phosphate synthetase 1 (CPS1) deficiency, that impairs the body's ability to process protein. When the body breaks down proteins, it produces ammonia ' a toxic substance that is usually processed by enzymes in the liver and excreted in urine. CPS1 deficiency compromises one of these enzymes, causing ammonia to accumulate in the blood, which can eventually damage the brain. The condition can be treated with a liver transplant, but about half of all babies with CPS1 deficiency die in early infancy. One of KJ's doctors, paediatrician Rebecca Ahrens-Nicklas at the Children's Hospital of Philadelphia in Pennsylvania, wondered whether there might be another solution ' correcting the faulty enzyme in his liver. She and Kiran Musunuru, a cardiologist at the Perelman School of Medicine at the University of Pennsylvania in Philadelphia, had a bold plan to treat children with rare genetic disorders using gene-editing therapies tailored to unique DNA sequences. KJ could be their first candidate....

A CRISPR'Cas9 gene-editing therapy has halved people's cholesterol levels in a small clinical trial ' raising hopes that, with further study, gene editing could one day be harnessed to provide a one-stop treatment for a common cause of heart disease. For the study, researchers used CRISPR to disable a gene called ANGPTL3 that helps to regulate levels of fatty molecules, including low-density lipoprotein (LDL) or 'bad' cholesterol and triglycerides, in the blood. Both types of molecule are linked to an increased risk of cardiovascular disease, and levels of both fell by roughly 50% in people who were treated with the highest dose of the therapy1. So far, only 15 people have received the treatment. But, if all goes well in future studies, investigators hope that gene editing might one day liberate many thousands of people from daily regimens of cholesterol-lowering medication. 'What a revolution to be able to do that,' says Luke Laffin, a specialist in preventative cardiology at the Cleveland Clinic in Ohio and a lead investigator on the trial. 'Conceptually, it's a great idea: we can move from chronic therapy to something that's one-and-done.'...

Cathy Tie left university to found her first biotechnology company at the age of 18. In the 11 years since, she has launched several more. Her first company helped genetic-testing firms to interpret their results; her second provides digital health-care services. Her latest venture, which announced some of its first key hires on 30 October, veers out of the mainstream. Tie, who has called herself Biotech Barbie, sometimes refers to her latest company as the Manhattan Project ' the name used for the US effort to develop an atomic bomb in the 1940s ' and now focuses her entrepreneurial ambitions on a controversial goal: altering the genome of human embryos to prevent genetic disorders. Plenty of scientists, however, are worried. Manhattan Genomics, the official name of her latest company, based in New York City was launched this summer. Tie co-founded the firm with Eriona Hysolli, former head of biological sciences at Colossal Biosciences, a Dallas, Texas firm focused on de-extincting species. Another company called Preventive in South San Francisco, California, announced on 30 October that it also intends to explore gene editing in human embryos....