Speciality pharmaceutical company Watson Pharmaceuticals Inc (NYSE:WPI) announced on Wednesday that its subsidiary Watson Laboratories Inc has received tentative approval from the US Food and Drug Administration on its Abbreviated New Drug Application (ANDA) for Fentanyl Citrate Buccal tablets, 100 mcg, 200 mcg, 300 mcg, 400 mcg, 600 mcg and 800 mcg.

Watson's Fentanyl Citrate Buccal tablets are a generic version of Cephalon's Fentora, which is used to treat breakthrough pain in cancer patients who are taking regularly scheduled doses of another narcotic (opiate) pain medication.

Cephalon is engaged in legal action against Watson, alleging that Watson's ANDA for Fentanyl Citrate Buccal tablets infringes certain of Cephalon's patents.

Final FDA approval of Watson's application remains subject to the expiration of the automatic stay of approval imposed under the provisions of the Hatch-Waxman Act.

According to IMS (product,search) Health data, Fentora recorded total US sales of approximately USD170m in the 12 months ending 30 April 2010.

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