Stoke Therapeutics Inc. and Biogen Inc. said Tuesday they are entering a collaboration to develop and commercialize a treatment for Dravet syndrome, a severe form of epilepsy that starts in childhood.

In exchange for $165 million, Biogen now has access to zorevunersen, a potential first-of-its-kind treatment for Dravet syndrome.

Biogen and Stoke Therapeutics have signed a partnership agreement to co-develop and sell Stoke’s experimental treatment for Dravet syndrome, a severe form of epilepsy, outside the U.S., the companies said this morning.

Stoke Therapeutics Inc. (Nasdaq: STOK) has pulled in Biogen (Nasdaq: BIIB) to help it develop and commercialize a treatment it’s working on for Dravet syndrome, a rare, debilitating form of epilepsy that affects children.