Modifying DNA was supposed to be a game changer. But drug companies and Wall Street are pulling back from the expensive-to-produce treatments, leaving parents to fund research on their own. When a biotech company promised to study a new treatment for her daughter’s disease, Nicole Johnson was elated. She’d been raising money to research potential cures for FOXG1 syndrome, a rare neurological disorder that had robbed her daughter of the ability to walk or talk. A Dallas-based biotech, Taysha Gene Therapies Inc., agreed to collaborate with her nonprofit on developing a gene therapy for the condition.

But two years ago, Taysha stopped developing the treatment and more than a dozen others. The decision was hardly unusual. Since 2021, drug companies have dropped more than 50 gene therapies. The rising number of abandoned treatments raises questions about whether modifying a patient’s DNA to cure rare diseases can be a lucrative business. And it’s sparked an effort from parents, scientists and entrepreneurs to rescue the drugs that have been left sitting on the shelf.