[Golfkid2Gadfly]

Zhang Haitao was a basketball-loving teenager who dreamed of going to a specialized sports high school when he got a pain in his right arm that just wouldn’t go away. It turned out to be acute lymphoblastic leukemia.

The discovery set Zhang and his family, from a village deep in the mountains of southwestern China's Sichuan province, on a journey familiar to most cancer patients — a revolving door of hospital visits, blood tests and three rounds of chemotherapy. It was then that Zhang’s doctor suggested a last-ditch option: an experimental gene therapy being trialed by a Chinese startup called Gracell Biotechnology Ltd.

After spending three weeks in the hospital in May — during which white blood cells were removed from his body, genetically engineered, and then infused back in — an analysis of Zhang’s bone marrow in June showed his body was clear of cancer.

Seven months later, monthly medical tests conducted at a hospital in the nearby Chinese metropolis of Chongqing show he remains cancer free.

“I don’t remember much about the treatment as I had a fever throughout,” said Zhang, who’s now almost 16 and spends his days playing video games and texting his friends. “It seems like a new solution that will give people hope.”

The therapy Zhang received was Chimeric Antigen Receptor-T cells, known as CAR-T, and it’s being hailed as one of the most exciting developments in the quest to cure cancer. First developed by Israeli scientist Zelig Eshhar in the 1980s, CAR-T re-works the genes of the body’s own immune cells so that they actively seek out and destroy cancer cells. While it’s been embraced by researchers and drugmakers around the world, perhaps nowhere is CAR-T having more impact — and being pushed dangerously close to its limits — than in China, home to the world’s biggest cancer population and some of the most ambitious experiments.

CAR-T works by supercharging T-cells, the body’s main line of defense against disease, so that they latch onto and destroy cancer. In clinical trials, leukemia patients who failed to respond to other therapies have shown remission rates of over 90% within two months of treatment.