Federal Circuit Rejects Anticipation Based On Misapplication Of “At Once Envisage” Framework
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  • Federal Circuit Rejects Anticipation Based On Misapplication Of “At Once Envisage” Framework

    On April 12, 2023, the Court of Appeals for the Federal Circuit (“CAFC”) affirmed a decision of the United States District Court for the District of Delaware in Case No. 1:19-cv-00474-KAJ, Judge Kent A. Jordan, invalidating asserted claims of plaintiff’s ’589 patent as obvious. UCB Inc. v. Actavis Laboratories UT Inc., __ F.3d __ (Fed. Cir. Apr. 12, 2023).  In its order affirming invalidity, the CAFC affirmed the district court’s holding of invalidity for obviousness but found legal error in the district court’s anticipation holding because it misapplied the CAFC’s decision in Kennametal, Inc. v. Ingersoll Cutting Tool Co., 780 F.3d 1376, 1381 (Fed. Cir. 2015).

    Plaintiff holds certain patents directed at transdermal therapeutic systems (“TTSs”), such as skin patches for delivering rotigotine, a pharmaceutical for treating Parkinson’s disease.  The patents claim mixtures of amorphous rotigotine with polyvinylpyrrolidone (“PVP”).  PVP stabilizes the amorphous rotigotine by increasing the glass transition temperature (“Tg”) of the mixture and preventing crystallization.  This is important because crystalline rotigotine cannot cross the skin barrier.

    In 2014, plaintiff brought a first infringement suit against defendant upon defendant’s filing of an Abbreviated New Drug Application (“ANDA”) for a generic form of a first version of plaintiff’s Parkinson’s TTS covered by one of plaintiff’s patents.  This first TTS version had a rotigotine to PVP ratio of 9:2.  Plaintiff was granted an injunction expiring March 2021, coincident with the expiration of plaintiff’s patent.  Subsequently, it was discovered that an unexpected and detrimental new crystalline form of rotigotine occurred in the first version of plaintiff’s Parkinson’s TTS, which rendered that product unstable.  Plaintiff filed for, and obtained, the ’589 patent covering a rotigotine to PVP ratio of 9:4 to 9:6 and released an improved version of its Parkinson’s TTS with a 9:4 ratio that prevented formation of the new crystalline form of rotigotine.

    In March 2019, plaintiff filed a suit for infringement of the later expiring ’589 patent based on defendant’s same ANDA.  The district court applied the “at once envisage” framework for anticipation articulated in Kennametal and found that certain of plaintiff’s earlier patents (the “Muller patents”) anticipate all asserted claims of the ’589 patent and that the asserted claims would have been obvious in view of the Muller patents.  Plaintiff appealed.

    With respect to anticipation, the CAFC explained that its precedent sets forth an established framework for analyzing whether a prior art reference anticipates a claimed range.  The framework varies depending on whether the prior art discloses a point within the claimed range or discloses its own range that overlaps with the claimed range.  If the prior art discloses a point within the claimed range, the prior art anticipates the claim.  On the other hand, if the prior art discloses an overlapping range, the court must evaluate whether the patentee has established that the claimed range, which includes only a portion of the range in the prior art and excludes other portions of the prior art range, is critical to the operability of the claimed invention.

    The CAFC concluded that the district court did not follow this framework in analyzing the Muller patents, which disclosed a rotigotine to PVP ratio range of 9:1.5 to 9:5 that overlapped with the asserted ’589 patent claimed range of 9:4 to 9:6.  Instead, the district court relied on the Kennametal “immediately envisage” line of cases to identify discrete points in Muller’s range and analyzed those discrete points as a point-within-a-range case.  Specifically, the district court relied on testimony to find that “[a] POSA would envisage examples at whole and half integer percentages of PVP and would not look in more granular detail.”  The “envisage” language stems from Kennametal, where the CAFC held that a reference can anticipate a claim “even if it does not expressly spell out all the limitations arranged or combined as in the claim, if a person of skill in the art, reading the reference, would at once envisage the claimed arrangement or combination.”  The CAFC concluded that, in so doing, the district court impermissibly converted the overlapping range Muller prior art analysis into a point-within-the-range case.

    The CAFC cautioned that Kennametal merely addresses whether the disclosure of a limited number of combination possibilities discloses one of the possible combinations and does not support the district court’s finding that Muller’s range recites a specific example.

    The CAFC next reviewed the district court’s holding of obviousness.  The district court held that the claimed range of ratios of rotigotine to PVP overlap with that disclosed in the Muller patents, and that plaintiff failed to rebut this prima facie case of obviousness.  In the district court, and on appeal, plaintiff argued that the Muller patents predate the discovery of the new rotigotine crystalline form and thus did not reflect the state of the art, and that a newer prior art reference (Tang) taught away from the range claimed in the ’589 patent.  Plaintiff also argued that the ’589 patent’s claimed range of “from about 9:4 to about 9:6” exhibited unexpected results.  Specifically, plaintiff argued that, given the stability failure of the first version of its Parkinson’s TTS, it was expected that the only slightly larger claimed range of “about 9:4 to about 9:6” would also exhibit the same failure.  Plaintiff also argued that the commercial success of its improved TTS, having a ratio of 9:4, rebutted the prima facie case of obviousness.  The district court, and the CAFC, rejected each of these arguments.

    First, the CAFC found there was sufficient evidence, including expert testimony and the fact that plaintiff’s first formulation stayed on the market for some time, to support the district court’s determination that, due to the similarities in the previously known and newly discovered crystalline forms of rotigotine, no cataclysmic change rendered the Muller prior art unusable.  Next, the CAFC agreed that Tang did not dissuade use of the claimed range by merely teaching an alternative optimal range.  The CAFC also agreed with the district court that there was sufficient expert testimony to show that the improved stability of the range claimed in the ’589 patent would have been expected given, e.g., the known stability-enhancing properties of PVP.  Last, the CAFC agreed that there was sufficient evidence to support the district court’s rejection of plaintiff’s “commercial success” argument.  The evidence included the existence of numerous other patents covering the improved product, calling into question the nexus between the success and the asserted ’589 patent.  The CAFC also found no error with the district court’s holding that any inference of obviousness from plaintiff’s commercial success evidence is weak because the Muller patents have operated as blocking patents dissuading competitors from developing a competing rotigotine TTS.
    Categories: ObviousnessPrior Art

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