Medical breakthroughs come with a human cost

Medical innovations can be risky, as this issue’s cover story on new CAR-T cell therapies for cancer reveals. The treatments, which tailor a patient’s own immune system cells to attack cancer, can be astonishingly successful. But CAR-T therapy can also be an untamed beast, unleashing a ferocious immune response that indiscriminately attacks the body. The challenge scientists face now is how to tame the therapy while retaining its cancer-killing powers.

It’s hardly the first medical advance to pose risks in its early days. Organ transplants are one of the most famous examples. In the 1960s, before the adoption of immune-suppressing drugs, fewer than 1 in 3 people