The doctrine of equivalents, a Supreme Court-created patent doctrine of vintage similar to inequitable conduct, arose in Graver Tank & Mfg. Co. v. Linde Air Products Co., 339 U.S. 605 (1950) (an uncharacteristically pro-patent decision by the Court, the doctrine recognized that an "unscrupulous copyist" could practice a claimed invention without literal infringement in some circumstances, and as a consequence the patent right could be turned into a "hollow and useless thing"):
Such a limitation would leave room for -- indeed encourage -- the unscrupulous copyist to make unimportant and insubstantial changes and substitutions in the patent which, though adding nothing, would be enough to take the copied matter outside the claim, and hence outside the reach of law. One who seeks to pirate an invention, like one who seeks to pirate a copyrighted book or play, may be expected to introduce minor variations to conceal and shelter the piracy. Outright and forthright duplication is a dull and very rare type of infringement. To prohibit no other would place the inventor at the mercy of verbalism and would be subordinating substance to form. It would deprive him of the benefit of his invention and would foster concealment rather than disclosure of inventions, which is one of the primary purposes of the patent system.
The doctrine fell into disfavor at the Federal Circuit during the 1990s and arguably provided the first inkling to the Court that the Federal Circuit's patent jurisprudence would benefit from the Court's closer oversight. In Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 36 (1997), and the seemingly interminable Festo v. Shoketsu Kinzoku Kogyo Kabushiki, the Supreme Court reiterated the vibrancy of the doctrine; nevertheless its successful assertion has continued to decline. Thus, the Federal Circuit's decision a few weeks ago in UCB, Inc. v. Watson Laboratories Inc., affirming a District Court's determination in ANDA litigation that the generic challenger's product infringed under the doctrine was a welcome surprise.
According to the Federal Circuit opinion, the case involved Neupro, a transdermal patch for delivering rotigotine (the (S) enantiomer of (-)-5,6,7,8-tetrahydro-6-[propyl-[2-(2-thienyl)ethyl]amino]-1-naphthalenol) for treating Parkinson's disease, for which U.S. Patent Nos. 6,884,434 and 8,232,414 were listed in the Orange Book. Individual Plaintiff's interests are set forth in the opinion as follows: UCB Mfg. Ireland Ltd. and LTS Lohmann Therpie-Systeme AG are co-assignees of '434 patent, and UCB Pharma GmbH is the assignee of the'414 patent; UCB Inc. owns the NDA for Neupro. The claims at issue in ANDA litigation against Watson Labs Inc. and Actavis Labs UT, Inc. are set forth in the opinion:
The '434 patent:
1. A transdermal therapeutic system comprising a self-adhesive matrix layer containing the free base (–)-5,6,7,8-tetrahydro-6-[propyl-[2-(2-thienyl)ethyl]amino]-1-naphthalenol [rotigotine] in an amount effective for the treatment of the symptoms of Parkinson's syndrome, wherein the matrix is based on [] an acrylate-based or silicone-based polymer adhesive system having a solubility of ≧5% (w/w) for the free base [rotigotine], all of said free base being present in the matrix in the absence of water; a backing layer inert to the components of the matrix layer; and a protective foil or sheet covering the matrix layer to be removed prior to use.
The '414 patent:
1. A polymorphic form of rotigotine characterized by at least one parameter selected from the group consisting of:
(a) a powder X-ray diffraction spectrum comprising at least one peak at the following °2θ angles (± 0.2): 12.04, 13.68, 17.72, and 19.01;
(b) a Raman spectrum comprising at least one peak at the following (±3 cm-1): 226.2, 297.0, 363.9, 737.3, 847.3, 1018.7, and 1354.3 cm-1;
(c) a DSC peak with a Tonset at 97°C. ± 2°C. measured with a heating rate of 10°/min; and
(d) a melting point of 97°C. ± 2°C.
2. The polymorphic form of rotigotine of claim 1, wherein the polymorphic form of rotigotine is characterized by at least the following powder X-ray diffraction peaks at °2θ angles (± 0.2): 12.04, 13.68, 17.72 and/or 19.01.
3. A polymorphic form of rotigotine having a powder X-ray diffraction spectrum substantially as shown in FIG. 1.
At trial, Defendants alleged that the claims of the '434 patent were invalid for obviousness and the claims of the '414 patent were anticipated, the latter theory on a unique set of facts. After FDA approval of the transdermal patch claimed in the '434 patent:
[B]atches of rotigotine patches were manufactured for distribution in the United States [and u]ntil August 2007, UCB manufactured Neupro patches by dissolving rotigotine in ethanol, among other steps, to create a rotigotine solution. It then prepared a coating mass from this solution and other components (including a silicone-based polymer), which, after drying, produced a matrix. The matrix did not contain crystalline rotigotine, and the rotigotine in the resulting patches, pre-distribution, was non-crystalline.
On August 7, 2007, an unknown solid precipitated during the dissolution step, causing UCB to halt manufacture of Neupro patches. Over the next few months, UCB investigated and determined that the solid was a polymorph of rotigotine, characterized by unique single-crystal X-ray diffraction parameters.
UCB filed a patent application to cover the newly dis-covered Form II polymorph of rotigotine. This resulted in the '414 patent . . . .
The earliest priority date for the '414 patent was November 28, 2007, and Plaintiffs did not adduce evidence of any earlier date of invention than this filing date. There was, on the other hand, evidence at trial that patients were treated with patches that contained this polymorph and that those patches were produced prior to the November 28, 2007 priority date of the '414 patent.
The basis for the District Court's determination that Defendants' generic patches containing rotigotine infringed under the doctrine of equivalents is that those patches contained a polyisobutylene (PIB) adhesive, not the acrylate-based or silicon-based adhesives recited in the '434 patent claims. The District Court found these embodiments to be "substantially similar" and that application of the doctrine of equivalents was not precluded by prosecution history estoppel, vitiation, ensnarement, or dedication to the public based on patentee's choice to claim narrowly. The District Court also rejected Defendants' invalidity contentions under §§ 102 and 103. The District Court found the asserted claims of the '414 patent to be invalid under § 102 based on the existence of the claimed polymorphic form of rotigotine in batches produced prior to the asserted priority date of November 28, 2007.
The Federal Circuit affirmed, in an opinion by Judge Chen joined by Judges Schall and Taranto. Regarding infringement of the '434 patent under the doctrine of equivalents, the opinion first discussed the lack of any limitation to the doctrine of equivalents. With regard to prosecution history estoppel, the Court noted that the claims that granted in the '434 patent had not been amended during prosecution, the usual route for finding estoppel under Festo. Specifically, the claim language that the patches included "acrylate-based or silicone-based polymer adhesive system having a solubility of ≥ 5% (w/w) for [rotigotine free base]" was never amended during prosecution, according to the Court. There had been a restriction requirement that involved an unclaimed group reciting the use of polyvinylpyrrolidone (PVP) as a solubility enhancer, which was useful for embodiments comprising silicone-based but not acrylate-based polymers. Both the District Court and the Federal Circuit rejected Defendants' argument that the election of embodiments not including PVP raised an estoppel because generally restriction requirement responses do not do so, citing Bayer Aktiengesellschaft v. Du-phar Int'l Research B.V., 738 F.2d 1237, 1243 (Fed. Cir. 1984). In addition, taking the rubrics on the proper application of estoppel to election decisions enunciated in Merck & Co. v. Mylan Pharm., Inc., 190 F.3d 1335, 1340 (Fed. Cir. 1999), the opinion states that the restriction requirement was not directed at the choice of adhesive and thus plaintiffs did not "give up" scope that would include Defendants' PIB adhesive.
Next, the opinion addressed Defendants' argument that Plaintiffs had relinquished scope that encompassed PIB by choosing to claim more narrowly. While the Supreme Court has recognized a "foreseeability" limitation to the doctrine of equivalents for claims amended during prosecution to which estoppel can apply, the opinion states that there has never been such a limitation to unamended claims. The opinion sets forth the logical necessity for this distinction: "known interchangeability" is the basis for finding equivalents, so that "foreseeability at the time of claim drafting is not a per se bar to the application of the doctrine of equivalents." Considering the totality of the evidence, the panel concluded that:
[T]here is not enough indication from the patent specification, claims, or the record evidence of the inventor's knowledge here to conclude that UCB surrendered polyisobutylene as a possible equivalent. In the absence of such facts, we agree with the district court that UCB's claiming of acrylates and silicates does not bar treating polyisobutylenes as an equivalent for infringement purposes.
And:
[W]e note as a policy matter that the patent system should not incentivize inventors to claim equivalents that they had not invented or tested, just because they know of the possibility of an equivalent, and also should not force inventors to delay filing for a patent on what they have invented while testing all known possible equivalents for fear of being unable to assert infringement under the doctrine of equivalents in the future.
Regarding the doctrine of vitiation (that equivalents fails "if it renders a claim limitation inconsequential or ineffective," Akzo Nobel Coatings, Inc. v. Dow Chem. Co., 811 F.3d 1334, 1342 (Fed. Cir. 2016), and cannot "eliminate [an] element in its entirety"), including PIB as an equivalent does not result in such elimination, according to the Federal Circuit, because it does not thereby include all adhesives within the scope of the claim. And regarding ensnarement, the panel agreed with the District Court that including PIB as an equivalent did not "ensnare" the prior art. In making this determination, the Court engaged in the exercise of crafting a hypothetical claim that literally encompassed embodiments comprising PIB as an adhesive, and then assessed the prior art asserted by Defendants to determine whether the hypothetical claim was patentable over that art. Unfortunately for Defendant, that art also disclosed acrylate-based and silicone-based adhesives, so that inclusion of PIB in the hypothetical claim did not uniquely encompass the prior art.
Turning to the merits, the panel deferred to the District Court on the factual determination, which in a bench trial required a finding of clear error. Here, the Federal Circuit did not find clear error in the District Court's finding that there were insubstantial differences between PIB and the acrylate-based and silicone-based adhesives recited in the claims and thus affirmed:
[A]t the time the '434 patent was filed, silicates, acrylates, and polyisobutylenes were the most commonly used pressure-sensitive adhesives in transdermal patches. The district court then identified a set of properties that silicates, acrylates, and polyisobutylenes share: they are pressure-sensitive, adhesive, biologically inert, non-irritating, and non-toxic. Thus, the district court found that a skilled artisan "would recognize that polyisobutylene is not substantially different from the classes of adhesives literally within the scope of the claims."
The District Court arrived at this conclusion despite evidence of differences in polarity, the presence of different functional groups, and the capacity to interact with crosslinking groups between polyisobutylene and acrylate-based and silicone-based adhesives, which the Court held were not substantial based on comparisons between Neupro and Defendants' generic alternatives.
Regarding Defendants' invalidity arguments, the panel affirmed the District Court's decision that failed prior art efforts to develop rotigotine transdermal patches neither anticipated nor rendered obvious the claims of the '434 patent. That art did not disclose a water-free patch having rotigotine in free base rather than salt form and thus comprised significant amounts of water (10-15% w/w) to solubilize the salt form of the drug. And none of the other art asserted by Defendants "fill[ed] the gap" in this disclosure, because they did not disclose rotigotine or other anti-Parkinson's disease drugs, and in particular did not disclose the free base form of the drug in the absence of water in the formulation. The Federal Circuit also affirmed the District Court's finding that other art, disclosing transdermal rotigotine administration by direct application to skin and transdermal patches not comprising water, did not render the claims of the '434 patent obvious because there was no "adequate rationale for combining the references' teachings" nor reasonable expectation of success at treating Parkinson's disease using a transdermal patch. The opinion finds the cited art as being "a list of thousands of possibilities out of which a skilled artisan would have to select the claimed combination as one to try" and thus would not have provided the skilled worker with a reasonable expectation of successfully achieving the claimed patch.
Turning to the '414 patent, the Federal Circuit affirmed the District Court's determination that the claimed rotigotine polymorph was used in the art prior to the earliest claimed priority date based on the presence of the polymorph in patches produced prior to that date, which constituted prior public use of the polymorph. Because (as with all factual determinations) appellate review of questions of fact before the district court is reviewed for clear error, the Federal Circuit found no clear error that Defendants had shown anticipation by clear and convincing error, and thus affirmed.
UCB, Inc. v. Watson Laboratories Inc. (Fed. Cir. 2019)
Panel: Circuit Judges Taranto, Schall, and Chen
Opinion by Circuit Judge Chen
