Abbott Laboratories v. Sandoz, Inc., (Fed. Cir. 2008)(Newman, J.)
Preliminary injunctions decisions are blessed with their own four-factor equitable test. I like to think of the test as having two required elements (likelihood of success on the merits and potential irreparable harm) and two optional factors (balance of the equities and public interest). A preliminary injunction (PI) will only issue when (1) the first two elements are demonstrated by the patentee and (2) the combined result of all four elements/factors weighs in favor of a PI.
The district court granted a preliminary injunction to Abbott to stop Sandoz from making or selling a generic version of its extended release clarithromycin antibiotic. In 75 pages of split opinion, the Federal Circuit affirmed with Judge Newman writing the majority opinion; Senior Judge Archer signing-on except for the two juicy parts: I and VI; and Judge Gajarsa in vigorous dissent.
The dispute revolves around the meaning of the required PI element of 'likelihood of success on the merits.' To win on this element, the patentee typically needs to provide evidence of infringement of at least one valid claim. Often this element turns on the defendant's rebuttal proof of invalidity. Here, the defendant provided some evidence of potential invalidity, but not conclusive evidence. Thus, while the defendant did raise a substantial question of the vulnerability of the patent, it did not provide any clear and convincing evidence of invalidity.
Judge Gajarsa argued that Federal Circuit precedent requires a PI be denied when substantial questions of validity are raised. This standard is exemplified in the Federal Circuit's recent Erico decision – which found the threshold "substantial question" met by evidence which simply "cast[s] doubt on the validity" of the asserted claims.
Judge Gajarsa: "Under our precedent, the likelihood of success factor is properly analyzed by considering whether the alleged infringer raises a substantial question as to validity."
On the other side, Judge Newman argues that a patentee may still be likely to succeed on the merits even when vulnerabilities and substantial invalidity questions are raised by the defense.
Judge Newman: "The question is not whether the patent is vulnerable; the question is who is likely to prevail in the end, considered with equitable factors that relate to whether the status quo should or should not be preserved while the trial is ongoing. The presentation of sufficient evidence to show the likelihood of prevailing on the merits is quite different from the presentation of substantial evidence to show vulnerability. "
Both sides are well supported by conflicting precedent, and this case may well be a good vehicle for an en banc discussion of preliminary injunctive relief.