CORRECTED - UPDATE 1-Cephalon says Nuvigil helps jet lag sleepiness

(Corrects chemical name of Nuvigil to armodafinil from modafinil in paragraph 4) (Updates with details)

BOSTON, April 6 (Reuters) - Cephalon Inc (CEPH.O) said on Monday that its sleep disorder drug Nuvigil helped people suffering from jet lag in a clinical trial.

Nuvigil is a longer-acting version of Cephalon's Provigil, which generated sales in 2008 of $988.4 million.

Both are approved to treat excessive sleepiness associated with narcolepsy, obstructive sleep apnea and shift work.

The Frazer, Pennsylvania-based drugmaker said data from a late-stage clinical trial of Nuvigil, also known as armodafinil, showed it reduced sleepiness associated with jet lag in people who traveled east from the United States to France.

Cephalon said that it will file an application with the U.S. Food and Drug Administration to add jet lag to the drug's list of approved indications.

Cephalon is preparing to launch Nuvigil in the third quarter of 2009. The company hopes it will make up for a likely decline in sales of Provigil once Provigil loses patent protection in 2012. (Reporting by Toni Clarke; Editing by Steve Orlofsky)