Actavis Elizabeth LLC v. Food and Drug Administration

The Food and Drug Administration (FDA) granted Shire Pharmaceuticals (Shire) five-year market exclusivity for Shire’s attention deficit hyperactivity disorder (ADHD) drug, lisdexamfetamine dimesylate, under the brand name Vyvanse. The FDA’s interpretation of its regulations allows five-year exclusivity for drugs containing derivative molecules of previously approved active moieties that are not in the form of an ester, salt, or other noncovalent derivative. Vyvanse was a drug that contained a derivative molecule of previously approved active moieties because once lisdexamfetamine enters the body, it undergoes a chemical conversion to produce dextroamphetamine, which had previously received FDA approval. In industry terms, lisdexamfetamine is a prodrug of dextroamphetamine, and the FDA finds prodrugs that are not esters, salts, or other noncovalent derivatives eligible for five-year exclusivity. Before the expiration of Shire’s exclusivity period, generic-drug competitor Actavis Elizabeth LLC (Actavis) filed an abbreviated new drug application (ANDA) for its generic drug lisdexamfetamine dimesylate, referencing Vyvanse. The FDA found Actavis’s ANDA was premature and returned it unfiled. Actavis filed a suit against the FDA to force the FDA to rescind its grant of exclusivity to Vyvanse and to accept Actavis’s ANDA. Shire intervened. The district court granted summary judgment for the FDA and Shire, and Actavis appealed. Because lisdexamfetamine dimesylate is a salt of lisdexamfetamine, Actavis argued this rendered it ineligible for five-year exclusivity because salts are not considered active moieties. Actavis specifically challenged the FDA’s interpretation that treats the entire molecule as that responsible for the action of the drug substance, and therefore a separate active moiety entitled to five-year exclusivity. In other words, Activas argued that five-year exclusivity should not be given to any drug containing a drug molecule that eventually produces a previously approved drug molecule in the body.