Soon after she received the treatment, Karen Koehler’s brain swelled. Her blood pressure plummeted. As she fell into a coma, her husband and sister sat at her bedside — urging the doctors to keep pushing her farther along the razor’s edge between life and death.
Koehler was undergoing a promising — and terrifying — experimental therapy that her oncologists hoped could rid her body of cancer entirely. It’s called CAR-T therapy, and it works by engineering the patient’s own immune cells to attack cancer.
