Zogenix has confirmed the efficacy of its experimental epilepsy drug in a second, late-stage clinical trial, paving the way for a marketing submission by the end of the year.

The small biotech company, based in Emeryville, Calif., said its lead drug, ZX008, reduced by more than half the average monthly convulsive seizures compared with a placebo in children and teenagers with Dravet syndrome, a rare and severe type of epilepsy.