Federal Circuit reverses grant of preliminary injunction where "substantial question" as to obviousness of invention is raised

Case: Abbott Laboratories v. Andrx and Teva Pharmaceuticals USA, Inc., No. 05-1433 (Fed. Cir. 6/22/06)

The One Sentence Summary: Over a dissent, the Federal Circuit reversed the granting of a preliminary injunction to Abbott, after Teva raised "substantial questions" regarding the obviousness of Abbott's patented invention of extended release clarithromycin.


What They Were Fighting About: Abbott developed and patented an extended release formulation of clarithromycin, a broad spectrum antibiotic. When Teva filed an Abbreviated New Drug Application for its own extended release formulation of clarithromycin, Abbott sought a preliminary injunction against Teva, claiming that Teva infringed claims 2, 4, and 6 of U.S. Patent No. 6,010,718 (“’718 patent”) and claim 2 of U.S. Patent No. 6,551,616 (“’616 patent”). Rejecting Teva’s argument that Abbott’s asserted patent claims were invalid for obviousness, the District Court granted the preliminary injunction. Teva appealed.

Federal Circuit Holdings:

• The Federal Circuit reversed, finding that Abbott was not likely to succeed on the merits, because Teva had raised substantial questions as to the obviousness of Abbott’s asserted claims.
• With regard to claims 2 and 4 of the ‘718 patent, which claimed (1) the use of an erythromycin derivative, (2) with an HPMC polymer, (3) that met certain pharmacokinetic parameters, the Court found that the prior art included the use of erythromycin with an alginate polymer that met the pharmacokinetic parameters specified. Taken together with prior art using an HPMC polymer to create an extended release formulation of azithromycin (another type of antibiotic), the Court found that all elements of the asserted claims in ‘718 existed in the prior art.
• Turning to the motivation to combine the elements contained in the ‘718 patent, the Court relied on one of Abbott’s earlier patent applications to demonstrate that the motivation existed prior to the ‘718 patent. Abbott argued that prior art combining azithromycin with an HPMC polymer was insufficient to reasonably motivate a person of skill in the art to combine clarithromycin with an HPMC polymer, because the two antibiotics were too dissimilar. However, in a previous patent claim, Abbott had claimed the use of azithromycin or clarithromycin with an alginate polymer to form an extended release antibiotic. Because the application explicitly disclosed only the clarithromycin formulation, but also claimed the azithromycin formulation, Abbott had represented that azithromycin and clarithromycin were interchangeable without undue experimentation. Thus, Abbott could not later claim that azithromycin and clarithromycin were so different as to prevent substitution of one with the other. In addition, because the difference between azithromycin and clarithromycin was that clarithromycin had a preferable half-life and metabolism, the difference actually made it more likely that clarithromycin could successfully be used in an extended release formulation, not less likely.
• With regard to claim 6 of the ‘718 patent and claim 2 of the ‘616 patent, claiming the reduction of gastrointestinal and “taste perversion” side effects through the use of an extended release formulation, the Court found that it was well known in the medical literature that reducing the blood concentration of a drug through use of an extended release formulation would reduce these types of side effects.
• Having found that Abbott was unlikely to succeed on the merits, given the substantial questions regarding the obviousness of its claims, the Court found that the parties had tied with regard to whether there would be irreparable harm. Having failed to demonstrate a likelihood of success on the merits, Abbott was no longer entitled to a presumption of irreparable harm. Moreover, Abbott had failed to demonstrate that damages would not compensate it. However, Teva had likewise failed to demonstrate that damages would suffice to compensate Abbott. Thus, the analysis favored neither party.
• The Court affirmed the District Court’s uncontested holding that the balance of hardships favored Abbott.
• With regard to the public interest factor, the Court found that, given that Abbott had failed to demonstrate a likelihood of success on the merits, the public interest was best served by denying the preliminary injunction.
• The dissent emphasized the wisdom of deferring to trial courts regarding preliminary injunctions meant to preserve the status quo between parties, pending litigation. Denying an injunction where a “substantial question” had been raised regarding validity of the asserted patent claims did not accord the proper level of deference to a trial court that had determined that a litigant was not likely to prove invalidity of a (presumptively valid) patent by clear and convincing evidence. Moreover, the majority failed to accord proper weight to its own determination that the balance of hardships favored Abbott. Overall, the dissent accused the majority of ignoring the District Court’s carefully reasoned opinion, engaging instead in an incorrect “de novo” review.