The early trial results, published in the New England Journal of Medicine, external, show the experimental treatment can be given safely to adolescents and young children, from the age of two onwards.
Stoke Therapeutics provided the drug that is given as a lower back injection to travel in spinal fluid to the brain, where it is needed.
Dravet syndrome is caused by a mutation in one of two copies of a gene, SCN1A, that tells brain cells how to make important communication channels for sending signals.
It means only half of the normal amount of sodium channels are produced in some neurons.
Zorevunersen is designed to help ramp up the production for healthy brain activity with fewer or no seizures.
Prof Helen Cross, one of the lead researchers from University College London’s Institute of Child Health and Great Ormond Street Hospital, says the results have been truly promising.
“It is exciting. It’s amazing.
“With improvements, that gives them real hope that they are able to carry out more normal lives, particularly with their families.
“And even perhaps, if we get the treatment right, get near normal living in the longer term.”