Shares of Zogenix zoomed 180 percent higher in midday trading Friday after positive results from a study on its treatment of a rare form of epilepsy.
At one point in early premarket trading where volume is light the shares had tripled.
The biotechnology company reported significant results in a Phase 3 trial of its drug ZX008, which is a treatment for Dravet syndrome. Zogenix stock traded at $12.88 per share at market close on Thursday, according to FactSet. It was trading near $36 in the early afternoon.
"We remain on track to submit applications for regulatory approvals in the U.S. and Europe in the second half of 2018," Zogenix CEO Stephen Farr said in a statement.
Farr said his company was "extremely pleased" with the treatment's results in children and young adults. In total, 119 patients participated in the ZX008 trial. One of the three dosage groups saw an average 64 percent reduction in monthly convulsive seizures compared to placebo treatments.
The drug also saw "clinically meaningful reductions" in the frequency of seizures, Zogenix said, as well as an increase in time between seizures.
GW Pharmaceuticals stock fell over 8 percent Friday as investors feared competition from Zogenix. GW Pharmaceuticals manufactures cannabis-based treatment Epidiolex, which is in Phase 3 trials to treat Dravet syndrome.
Based in Emeryville, California, Zogenix expects results from a second trial in the first half of next year.
Correction: An earlier version misspelled Dravet.