King Pharmaceuticals Inc reported that the Food and Drug Administration has approved supplemental New Drug Applications (sNDA), which provide that Unithroid (levothyroxine sodium tablets, USP) and Levo-T (levothyroxine sodium tablets, USP) are bioequivalent and therapeutically equivalent to Levoxyl (levothyroxine sodium tablets, USP).

Despite the Company's expectation to the contrary, the FDA granted these approvals without requiring certification against King's patent number 6,555,581 (the '581 Patent), which pertains to Levoxyl and is listed in the FDA's publication entitled Approved Drug Products with Therapeutic Equivalence Evaluations, commonly known as the "Orange Book". King is currently evaluating the appropriateness of such approvals and considering potential legal recourse, company said in a release.

Brian A Markison, acting president and CEO of King, noted, "The American Thyroid Association (ATA), The Endocrine Society (TES), and the American Association of Clinical Endocrinologists (AACE) issued a joint release regarding their concerns with respect to the methodology used by the FDA to determine bioequivalence. In their release these organizations indicate that there is the potential for health issues that may arise from this action which is of great concern to our Company, healthcare professionals, and ultimately patients who utilize levothyroxine sodium products."

King also said the receipt of the FDA's denial of the Company's Citizen Petition challenging the appropriateness of the FDA's bioequivalence methodology for levothyroxine sodium tablets.

The '581 Patent' is a utility patent that covers the Company's novel Levoxyl product. The '581 Patent extends through February 15, 2022.

King, headquartered in Bristol, Tennessee, is a vertically integrated branded pharmaceutical company.