(Reuters) – Supernus Pharmaceuticals Inc’s experimental epilepsy drug Oxtellar XR won marketing approval from the U.S. Food and Drug Administration, the second drug approval for the company since it went public in May.

Oxtellar XR’s final marketing approval follows the tentative approval given in late-June to Supernus’s Trokendi XR — a generic epilepsy treatment.

The company plans to launch Oxtellar in the first quarter of 2013.

Rockville, Maryland-based Supernus is developing several other drugs for epilepsy, depression and attention deficit hyperactivity disorder.

Supernus’s shares closed at $12.97 on Friday on the Nasdaq.

(Reporting By Pallavi Ail in Bangalore; Editing by Supriya Kurane)