US company Cephalon faces an extra wait of up to three months before it will hear whether its new narcolepsy drug Nuvigil can be launched onto the US market.

The US Food and Drug Administration has extended its review of the Nuvigil (armodafinil), a single-isomer version of Cephalon’s already-marketed narcolepsy treatment Provigil (modafinil), until April 30. The company said it hopes to be able to introduce the new product in the middle of 2006.

Nuvigil is a key element in Cephalon’s strategy to preserve its important narcolepsy treatment franchise from generic competition. Provigil is expected to bring in revenues of more than $500 million in 2005, nearly half of Cephalon’s total revenue, but has been the subject of numerous patent challenges that raise the threat of generic competition.

Now, Cephalon has cut a deal with Barr Laboratories that could help it fend off generic rivals to Provigil and another of its key products, the painkiller Actiq (transmucosal fentanyl citrate). The new agreement ends patent litigation between the firms. Cephalon has already reached similar settlements over Provigil with Mylan Laboratories, Teva Pharmaceutical Industries and Ranbaxy Laboratories.

Barr will now be able to launch a generic version of Provigil in October 2011, or earlier if another generics company successfully challenges Cephalon’s patents and brings a copycat version to market. This entry date would be set back to April 2012 if Cephalon carries out trials of the drug in children and gains a patent extension as a result.

For Actiq, Cephalon has given Barr a non-exclusive right to sell a generic version from February 3, 2007, or six months earlier if the company does not get approval for a patent extension based on paediatric trials. Barr could also launch its version earlier, although this will depend on Cephalon winning approval for a new melt-in-the-mouth formulation of the drug – fentanyl effervescent buccal tablet (FEBT).

Cephalon said the settlement struck a balance “between protecting our intellectual property rights and providing more certainty to our business through at least 2011,” according to John Osborn, the firm’s general counsel.

The company is also developing a once-daily version of modafinil, dubbed Sparlon, as a treatment for attention-deficit hyperactivity disorder. Cephalon said last week it hopes to launch this product in the second quarter of the year, pending a successful FDA advisory committee meeting scheduled for March 23. The agency issued an ‘approvable’ letter for Sparlon last November.