In a case involving generic versions of Pfizer’s high blood pressure drug Norvasc® (amlodipine besylate) and the availability and applicability of both 180-day generic drug exclusivity and pediatric exclusivity the United States District Court for the District of Columbia denied all requests for preliminary injunction related to amlodipine besylate tablets and supported the U.S. Food and Drug Administration’s (FDA) position concerning Mylan’s current status as holder of the only approved Abbreviated New Drug Application (ANDA) for all strengths of this product. In the decision, the district court confirmed the position taken by the FDA that all of the unapproved amlodipine besylate ANDAs are currently blocked from approval by pediatric exclusivity. Mylan Labs. et al. v. Leavitt et al., Case No. 07-579 (D.C. D.C., Apr. 30, 2007) (Urbina, J.)

Under the Federal Food, Drug, and Cosmetic Act , 21 U.S.C. § 301 et seq. (1994), a brand manufacturer (here Pfizer) is entitled to a period of pediatric exclusivity if, among other things, “in the patent infringement litigation resulting from the certification the court determines that the patent is valid and would be infringed.” In addressing the parties’ arguments, Judge Urbina held that since 21 USC § 355 a (c) (2) (B) is silent “as to the particular court which may determine the patent dispute,” the earlier order from the District Court for the Northern District of Illinois, in Pfizer v. Apotex, triggered Pfizer’s pediatric exclusivity and “is effective and remains so during the pendency of the appeal unless the district court’s judgment is stayed or until the Federal Circuit issues its mandate.”

The parties disputed whether Apotex is subjected to Pfizer’s period of pediatric exclusivity. Judge Urbina reasoned that § 355 a manifests a clear Congressional intent that pediatric exclusivity not block the approval of an ANDA where the ANDA applicant has prevailed in the Hatch-Waxman ANDA-triggered litigation under paragraph IV (where the generic drug manufacturer certifies that any applicable listed patent is invalid or not infringed). He concluded that the “FDA’s decision to exempt Apotex in light of its status as a prevailing party in challenging Pfizer’s patent is reasonable and is not contrary to the language in Hatch-Waxman.”

The court then turned to the FDA’s ruling that Apotex is the sole beneficiary of the Federal Circuit’s invalidity ruling regarding Pfizer’s Norvasc patent. Here, the court concurred with the FDA that because the Federal Circuit invalidated only three claims of Pfizer’s patent and left several claims untouched, Pfizer’s patent remains valid as to the remaining claims and is presumed to be properly listed in the Orange Book. Judge Urbina further agreed, that “[u]ntil Teva succeeds in its own patent litigation with Pfizer or until administrative or legal action completely de-lists Pfizer's patent from the Orange Book”, the FDA’s decision to withhold market approval for Teva’s generic drug remains in effect.

Finally, Mylan challenged the FDA’s ruling that its 180-day market exclusivity does not extend beyond the expiration of Pfizer’s patent. Mylan argued that “nothing in the text or legislative history of the Hatch-Waxman Act indicates that generic exclusivity is forfeited upon patent expiration.” Judge Urbina, however, held that under Hatch-Waxman, a paragraph IV certification is no longer valid upon patent expiration and must be converted to a certification under paragraph II, the portion of the statute relating to certification of a generic drug where the applicant asserts the proposed generic drug would not infringe as a result of patent expiration. At that time, a submitted ANDA becomes eligible for immediate approval.