UPDATE 2-Zogenix stock soars after epilepsy test success

(Updates shares, adds background of the drug)

Sept 29 (Reuters) - Zogenix Inc's experimental treatment for a rare form of epilepsy met the main goal in a late-stage study, the company said on Friday, putting it on track to request regulatory approval next year and more than tripling the value of its shares.

The drug - ZX008 - was shown to be superior compared to a placebo in reducing the frequency of seizures in children with Dravet syndrome, a genetic dysfunction in the brain which results in potentially fatal, long-lasting, fever related seizures that do not respond to standard treatment.

Zogenix also said the drug reduced the number of patients suffering seizures in comparison with a placebo.

The company said it expected to report data from a second late-stage trial in the first half of next year and remained on track to submit regulatory approvals for the drug in the United States and Europe in the second half of 2018.

Zogenix acquired ZX008 in 2014 after buying Brabant Pharma.

Shares in the U.S.-based drug developer soared to $40 in premarket trading from a close of $12.87 on Thursday. (Reporting by Manas Mishra in Bengaluru; Editing by Sriraj Kalluvila and Patrick Graham)