News Detail Banner
All News & Events

Article: August 2017: Life Sciences Litigation Update

Business Litigation Reports

Mylan Institutional LLC v. Aurobindo Pharma Ltd., No. 2017-1645, 2017 WL 2192945 (Fed. Cir. May 19, 2017). On May 19, 2017, the Federal Circuit issued a precedential opinion in Mylan Institutional LLC v. Aurobindo Pharma Ltd. The decision provides useful guidance for the application of the doctrine of equivalents with respect to chemical compounds. In its opinion, the Federal Circuit attempted to address the issue of “sparse and confusing case law concerning equivalents, particularly the paucity of chemical equivalence case law, and the difficulty of applying the legal concepts to the facts.” Id. at 12. The Federal Circuit also noted that “the law on the doctrine of equivalents as applied to chemical materials is not clear, and its misapplication can lead to unsound results.” Id.

In Mylan, the patentee held two patents concerning methods of making isosulfan blue (“ISB”), a dye used to map lymph nodes, using silver oxide as a solvent (the “process patents”). Id. at 2. The patentee also held a third patent concerning the purity of the ISB dye, but that patent is not relevant to the doctrine of equivalents issues discussed in this article. The accused infringer in Mylan, Aurobindo Pharma Ltd (“Aurobindo”), claimed that it did not infringe the process patents because it made ISB using manganese dioxide instead of the claimed silver oxide. Mylan countered by arguing that Aurobindo’s process infringed the process patents under the doctrine of equivalents because the substitution of manganese dioxide for silver oxide was not sufficient to escape an infringement finding under the either the “function-way-result” test (whether the accused product performs substantially the same function in substantially the same way to obtain the same result) or “insubstantial difference” test (whether the accused product or process is substantially different from what is claimed) established by the Supreme Court in 1950 in Graver Tank & Manufacturing Co. v. Linde Air Production Co. Chemically, both manganese dioxide and silver oxide are oxidizing agents, but manganese dioxide has a substantially stronger oxidation strength than silver oxide.

The district court agreed with Mylan and found that Aurobindo likely infringed the process patents under the doctrine of equivalents based on a finding that:

the difference in oxidation strength between silver oxide and manganese dioxide is “irrelevant” under both the “function-way-result” (“FWR”) and “insubstantial differences” tests for equivalence.

Id. at 6. Accordingly, the district court issued a preliminary injunction precluding Aurobindo from making, using, selling, offering to sell, and importing the accused ISB product. Id at 2. On appeal, Aurobindo argued that it had raised a substantial question of infringement under the doctrine of equivalents because manganese dioxide works in a substantially different way than silver oxide because of the difference in oxidation strength.

In its opinion, the Federal Circuit addressed both the function-way-result test (also referred to as the FWR or “triple identity” test) and insubstantial differences test. The Federal Circuit explained that the “chemical arts” were generally not well-suited for consideration under the triple identity test. Id. at 13. Specifically, the Federal Circuit explained:

Especially when evaluating an equivalents dispute dealing with chemical compositions having many components, chemical compounds with many substituents (which are usually claimed as separate limitations), and those having a medical or biological use, it is often not clear what the “function” or “way” is for each claim limitation. How a particular component of a composition, or substituent of a compound, functions in a human or animal body, or in what way, may not be known or even knowable (although, as technology evolves, that may change). And precedent requires that, for infringement under the doctrine of equivalents, each limitation must satisfy an equivalence test.

Id. at 14. In the context of admonishing the district court not to ignore the “way” prong of the triple identity test, the Federal Circuit explained that the “function” and “way” portions of the triple identity test often will overlap. Id. at 15.

The Federal Circuit further explained that “a compound may appear to be equivalent under the FWR test, but not under the substantiality of the differences test” and used aspirin and ibuprofen as examples:

consider the well-known compounds aspirin and ibuprofen, which chemists would not usually consider to be structural equivalents under the insubstantial differences test. Chemical compounds are characterized by their structures, and these two compounds differ substantially in structure (see appendix). However, the two compounds would seem to be substantial equivalents under the FWR test. They each provide analgesia and anti-inflammatory activity (“function”) by inhibiting prostaglandin synthesis (“way”) in order to alleviate pain, reduce fevers, and lessen inflammation (“result”).

Id. at 17. The aspirin/ibuprofen example was intended to show a situation where the triple identity test would lead a court to the wrong conclusion because “a compound may appear to be equivalent under the FWR test, but not under the substantiality of the differences test.” Id.

The Federal Circuit stated that both the function- way-result test and the insubstantial differences tests have been “blessed” by the Supreme Court, “leaving to the lower courts in future cases the choice of which to apply.” Id. at 13. However, the Federal Circuit gave a clear indication that the substantial difference test would likely prove superior in determining whether manganese dioxide and silver oxide are equivalents within the context of the process patents at issue:

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. Those differences may well be relevant to equivalence at trial.

Id. at 18. Thus, while the Federal Circuit stated that the triple identity test still can be used, it admonished the district court that it should not use the triple identity test alone and that the insubstantial differences test is likely more appropriate in the chemical arts.

Despite its critical treatment of the application of the triple identity test by the court below, the Federal Circuit let the preliminary injunction against Aurobindo stand on other grounds.

Ltd., No. 2017-1645, 2017 WL 2192945 (Fed. Cir. May 19, 2017). On May 19, 2017, the Federal Circuit issued a precedential opinion in Mylan Institutional LLC v. Aurobindo Pharma Ltd. The decision provides useful guidance for the application of the doctrine of equivalents with respect to chemical compounds. In its opinion, the Federal Circuit attempted to address the issue of “sparse and confusing case law concerning equivalents, particularly the paucity of chemical equivalence case law, and the difficulty of applying the legal concepts to the facts.” Id. at 12. The Federal Circuit also noted that “the law on the doctrine of equivalents as applied to chemical materials is not clear, and its misapplication can lead to unsound results.” Id.In Mylan, the patentee held two patents concerning methods of making isosulfan blue (“ISB”), a dye used to map lymph nodes, using silver oxide as a solvent (the “process patents”). Id. at 2. The patentee also held a third patent concerning the purity of the ISB dye, but that patent is not relevant to the doctrine of equivalents issues discussed in this article. The accused infringer in Mylan, Aurobindo Pharma Ltd (“Aurobindo”), claimed that it did not infringe the process patents because it made ISB using manganese dioxide instead of the claimed silver oxide. Mylan countered by arguing that Aurobindo’s process infringed the process patents under the doctrine of equivalents because the substitution of manganese dioxide for silver oxide was not sufficient to escape an infringement finding under the either the “function-way-result” test (whether the accused product performs substantially the same function in substantially the same way to obtain the same result) or “insubstantial difference” test (whether the accused product or process is substantially different from what is claimed) established by the Supreme Court in 1950 in Graver Tank & Manufacturing Co. v. Linde Air Production Co. Chemically, both manganese dioxide and silver oxide are oxidizing agents, but manganese dioxide has a substantially stronger oxidation strength than silver oxide.The district court agreed with Mylan and found that Aurobindo likely infringed the process patents under the doctrine of equivalents based on a finding that:the difference in oxidation strength between silver oxide and manganese dioxide is “irrelevant” under both the “function-way-result” (“FWR”) and “insubstantial differences” tests for equivalence.Id. at 6. Accordingly, the district court issued a preliminary injunction precluding Aurobindo from making, using, selling, offering to sell, and importing the accused ISB product. Id at 2. On appeal, Aurobindo argued that it had raised a substantial question of infringement under the doctrine of equivalents because manganese dioxide works in a substantially different way than silver oxide because of the difference in oxidation strength.In its opinion, the Federal Circuit addressed both the function-way-result test (also referred to as the FWR or “triple identity” test) and insubstantial