UPDATE 1-FDA delays decision on Cephalon drug for jet lag

* FDA delays decision on sleep disorder drug by 3 months

* New date for Cephalon’s drug for jet lag March 29

NEW YORK, Dec 21 (Reuters) - U.S. health regulators have delayed a decision on whether to approve Cephalon Inc's CEPH.O sleep disorder drug Nuvigil to treat sleepiness caused by jet lag by three months, the company said on Monday.

In a surprise move earlier this year, the U.S. Food and Drug administration granted a priority review to Cephalon’s application and set a Dec 29 date for deciding whether to approve the new use for Nuvigil.

But the FDA informed Cephalon that it needs more time for a full review and extended the action date to March 29, the company said.

Priority review status, under which the FDA makes its approval decision within six months rather than the usual 10- to 12-month review period, is typically reserved for medicines that are considered to have potentially significant advancements over existing therapies.

Cephalon is seeking approval to market Nuvigil specifically for “improving wakefulness in patients with excessive sleepiness associated with jet lag disorder due to eastbound travel.”

The drug is already approved for patients who suffer from excessive sleepiness due to sleep apnea, narcolepsy or shift work disorder.

Cephalon began selling Nuvigil, a follow-up to its flagship sleep disorder drug Provigil, in June in the United States. Analysts on average expect Nuvigil annual sales to reach $705 million in 2013, according Thomson Reuters I/B/E/S. (Reporting by Bill Berkrot, editing by Leslie Gevirtz)