Federal Circuit Provides Guidance on Application of Doctrine of Equivalents to Chemical Materials

On May 19, 2017, the Federal Circuit provided important guidance regarding the proper application of the doctrine of equivalents, particularly as it pertains to cases involving non-mechanical arts.  In Mylan Institutional, LLC v. Aurobindo Pharma Ltd., No. 2017-1645, slip op. (Fed. Cir. May 19, 2017) (precedential), the Federal Circuit affirmed a district court decision granting a preliminary injunction, but found errors in the district court’s evaluation of infringement under doctrine of equivalents with respect to two of the three asserted patents.  Those errors, the Federal Circuit noted, appeared to largely stem from the difficulties in applying the doctrine to chemical materials.

Under Supreme Court precedent, the doctrine of equivalents may be evaluated under two frameworks—the FWR test (i.e., whether the accused product performs substantially the same function in substantially the same way to obtain the same result) or the insubstantial differences test (i.e., whether the accused product or process is substantially different from what is patented).  Maylan, slip op. at 12 (citing Graver Tank & Mfg. Co. v. Linde Air Prod. Co., 339 U.S. 605, 608-09 (1950)).  The Federal Circuit observed, however, that “the law on the doctrine of equivalents as applied to chemical materials is not clear.”  Id.  Though it acknowledged the Supreme Court has “recognized the use of FWR generally in chemical cases,” the Federal Circuit indicated that cases involving “the chemical arts” are particularly likely to not be “well-suited to consideration under the FWR test.”  Id. at 13.

In Mylan, the issue turned on whether silver oxide and manganese dioxide were equivalents, and the Federal Circuit concluded that the district court’s analysis of that issue under the FWR test “was flawed by being unduly truncated and hence incomplete.”  Id. at 14.  Specifically, the Federal Circuit found that “the district court did not address the ‘way’ prong of the FWR analysis . . . or it performed a ‘way’ analysis without considering critical factors under that prong, namely, the relative oxidation strengths of silver dioxide and manganese dioxide, as well as the use of an acid in the accused process.”  Id. at 15-16.  Either way, the Federal Circuit commented, the district court erred.  Id. at 16.

The Federal Circuit then suggested that on remand, the district court “may wish to consider whether the substantiality of the differences test may be more applicable in this case,” noting that “the FWR test may be less appropriate if it cannot capture substantial differences between a claimed and accused compound.”  Id. at 16-17.  The Federal Circuit further observed:

Manganese dioxide and silver oxide are substantially different in many respects. For example, manganese and silver are in different groups of the Periodic Table.  In oxide form, manganese has an oxidation state of +4, while silver is +1.

Id. at 18.  According to the Federal Circuit, “[t]hose differences may well be relevant to equivalence at trial” and therefore the “choice of test under the doctrine of equivalents may matter.”  Id.

Parties pursuing or defending against a doctrine of equivalents theory of infringement in cases involving non-mechanical arts, and particularly those involving chemical arts, should consider the Federal Circuit’s guidance in Mylan and carefully evaluate whether the FWR test or the insubstantial differences is more suitable to the facts of their case.

Other Notable Decisions – Week of May 19, 2017

Arcelormittal v. AK Steel Corp., No. 2016-1357 (Fed. Cir. May 16, 2017) (precedential): In a split opinion, the Federal Circuit in ArcelorMittal affirmed a district court’s retention of subject matter jurisdiction following the filing of a covenant not to sue.  “Although a patentee’s grant of a covenant not to sue a potential infringer can sometimes deprive a court of subject matter jurisdiction,” the majority noted that the “patentee bears the formidable burden of showing that it could not reasonably be expected to resume its enforcement efforts against the covenanted, accused infringer.”  And because the patentee did not “unconditionally assure Defendants and their customers that it would never assert” the claims against them, the majority found the patentee had not met its burden.

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