For decades, cystic fibrosis has resisted the promise of gene therapy, its genetic complexity and the body's own immune defenses conspiring against lasting solutions. Now, researchers at Johns Hopkins University have demonstrated in primates that a single inhaled dose of a modified gene therapy can sustain measurable effects in the lungs for at least six months, while provoking only a minimal immune response — a pairing of durability and tolerance that has long eluded the field. The finding does not announce a cure, but it reframes the question: not whether gene therapy can work for CF, but ho