Chinese researchers report that a chemogenetic gene therapy cut seizure frequency by an average of 92.6% in three men with drug-resistant mesial temporal lobe epilepsy, in what is described as China's first human trial of the approach. The results appeared in the New England Journal of Medicine.
A viral vector was delivered under MRI guidance to hippocampal neurons, making them respond to a drug. Patients then took low doses of clozapine every eight hours, starting two weeks after surgery. Monthly seizures fell from 4.5 to 0.5 in two patients and from 4 to 0 in the third. Follow-up lasted 12 months for the first patient and eight months for the other two, with no serious adverse effects reported.
The trial was designed to test safety, has only three participants and no control group. Commentators note it is unclear whether the gain came from the gene therapy, the clozapine or both. Chinese teams are reportedly running at least seven trials of this kind.