“Three people with epilepsy resistant to drug treatment saw the number of seizures they had per month fall by more than 90%, after gene-laden viruses were infused directly into their brains as part of an early-stage clinical trial.

In each participant, the gene therapy was precisely targeted to a small patch of brain tissue that was the source of their seizures. The viruses carried a gene that makes neurons sensitive to a specific drug, which works like a dimmer switch for the therapy. By combining gene therapy with a drug — an approach known as chemogenetics — researchers can adjust a treatment’s potency, which is not possible with other types of gene therapy. The trial participants did not experience serious side effects.”

From Nature.