Sciele Pharma v. Lupin, No. 2012-1228 (Fed. Cir.)
In a precedential decision today, the Federal Circuit vacated a preliminary injunction that had been entered against Lupin in the ANDA litigation over Lupin's generic version of FORTAMET (metformin extended-release tablets). This is the second preliminary injunction against Lupin that the Federal Circuit has vacated in the litigation.
The U.S. District Court for the District of Delware entered the first preliminary injunction against Lupin in December 2011. The Federal Circuit vacated the injunction on February 6, 2012, because the "district court's order imposing the preliminary injunction failed to even address Lupin's obviousness arguments." On remand shortly therafter, the district court again entered a preliminary injunction against Lupin. Lupin then moved for a stay, which the district court denied. Lupin appealed again to the Federal Circuit, which ordered expedited briefing, held oral arguments on April 18, 2012, and, later the same day, granted Lupin's request to stay the second preliminary injunction.
Lupin argued in the appeal that the presumption of validity should not apply because the PTO erroneously granted the asserted claims of the patent-in-suit, U.S. Patent No. 6,866,866. Sciele argued, on the other hand, that there should be a heightened presumption of validity because the prior art references relied upon by Lupin (Cheng and Timmins) were before the PTO during prosecution. The Federal Circuit explained that, while new evidence not considered by the PTO "may carry more weight than evidence previously considered," the burden of proof required to prove invalidity, clear and convincing evidence, never changes:
The burden does not suddenly change to something higher--"extremely clear and convincing evidence" or "crystal clear and convincing evidence"--simply because the prior art references [relied on to prove invalidity] were considered by the PTO. In short, there is no heightened or added burden that applies to invalidity defenses that are based upon references that were before the Patent Office. The burden is always the same, clear and convincing evidence.
The Federal Circuit next addressed the merits of Lupin's invalidity argument, i.e., that the asserted claims of the '866 patent are invalid as obvious over Cheng and Timmins. The asserted claims are directed to controlled-release dosage forms of metformin providing a mean time to maximum plasma concentration (Tmax) of between 5.5 and 7.5 hours. According to the Federal Circuit, Cheng discloses all of the limitations of the asserted claims except for the Tmax range of 5.5 to 7.5 hours (instead disclosing a Tmax of 8-12 hours). In addition, while Timmins discloses a median Tmax and not the claimed mean Tmax, Timmins, according to the Federal Circuit, "also provides the raw data from which one skilled in the art could compute the range of possible mean Tmax values." According to the court, "[b]ased on this data, one skilled in the art would understand that the mean Tmax in Timmins must fall between 4.67 and 6.33 hours." Thus, according to the court, Timmins "teaches one skilled in the art to lower the Tmax of Cheng." This, in the Federal Circuit's view, was sufficient to raise a substantial question of validity that should have precluded a preliminary injunction.
To buttress its findings on the issue of obviousness, the Federal Circuit cited statements that the patentee made during prosecution in support of enablement:
During prosecution the applicant indicated "that one skilled in the art would be able to manipulate the processes and formulations of the [prior art] by other methods to obtain the claimed pharmacokinetic parameters of the present invention by routine experimentation. While [Sciele] argued, and the district court seemed to accept, that this statement applies only to enablement, we are hard pressed to understand this distinction. Coupled with the motivation to lower the Tmax, as disclosed in Timmins, the applicant's characterization of the predictability and skill in the art during prosecution provides further evidence that it would have been a routine and obvious design choice to make an extended-release dosage form with a lower Tmax.
Quoting KSR, the Federal Circuit concluded, "After all, 'if a person of ordinary skill can implement a predictable variation, section 103 likely bars its patentability.'"
Accordingly, the court vacated the preliminary injunction and remanded the case to the district court for further proceedings.