Doctrine of equivalents (DOE) can be applied as a mechanism to hold a party liable for patent infringement even if the product or process does not literally infringe a patent claim, if the difference is “insubstantial”. Warner-Jenkinson Co. v. Hilton Davis Chem. Co. (1997) Findings of infringement under DOE, particularly in biotechnology related cases, have often been considered an exception rather than the rule. One such exception is the recent Federal Circuit nonprecedential decision in Jennewein Biotechnologie GmbH v. International Trade Commission, September 17, 2020, Chen, R. (Glycosyn LLC, the patent owner, joined as an Intervenor). The Federal Circuit affirmed an exclusion order from the International Trade Commission (ITC) relying on an application of DOE to find infringement supported by substantial evidence.

Glycosyn’s ITC complaint under 19 U.S.C. § 1337, alleged that human milk oligosaccharides “HMOs” imported by Jennewein infringed Glycosyn’s U.S. Patent No. 9,970,018 (’018 patent). Claim 1 of the ‘018 patent is directed to a method for producing a fucosylated oligosaccharide in a bacterium and requires that, among other things, the bacterium contains “an exogenous functional β-galactosidase gene comprising a detectable level of β-galactosidase activity that is reduced compared to that of a wild-type E. coli bacterium, wherein the level of β-galactosidase activity comprises between 0.05 and 200 units”.

At the center of the dispute is whether Jennewein’s strains satisfy the claim limitations requiring “exogenous functional β-galactosidase gene” and “the level of β-galactosidase activity comprises between 0.05 and 200 units”. Jennewein argued that its strains do not have an “exogenous functional β-galactosidase gene” because they are engineered to express functional β-galactosidase only under certain temperature. More importantly, Jennewein argued that its strains express lacZα and lacZΩ, as separate gene fragments and lacZα is endogenous. Because the lacZΩ fragment is expressed at 42°C (but not at 30°C), the two fragments produce active β-galactosidase, only under these specific conditions and not throughout the process.

Jennewein also argued that negative control strains were required to determine the Miller values between 0.05 and 200 units and that such controls would demonstrate Jennewein’s strains have β-galactosidase activity outside the claimed range.

The Commission rejected Jennewein’s arguments finding infringement under DOE because Jennewein’s engineered β-galactosidase gene including an exogenous lacZΩ fragment is equivalent to an “exogenous functional β-galactosidase gene” required by the ’018 patent. Additionally, the claim language did not require that the E. coli demonstrate β-galactosidase activity between 0.05 and 200 units throughout the process and only at some point in time and no negative control was needed to correctly perform the Miller assay.

The CAFC affirmed the Commissions’ finding of infringement under DOE. Although nonprecedential, this case serves as a reminder that DOE still plays a significant role in biotech litigation and can change the outcome of the case.

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Photo of Tamaria Dewdney Tamaria Dewdney

Tamaria is a law clerk in the Litigation Department, and a member of the Life Sciences Patent practice. Her primary area of focus is in the area of intellectual property, where she works with life sciences clients of all sizes in the preparation…

Tamaria is a law clerk in the Litigation Department, and a member of the Life Sciences Patent practice. Her primary area of focus is in the area of intellectual property, where she works with life sciences clients of all sizes in the preparation and prosecution of patent applications.

Prior to joining Proskauer, Tamaria was a post-doctoral fellow at the Harvard Medical School/Dana-Farber Cancer Institute, where she characterized cellular and viral determinants that dictate HIV-1 nuclear import and integration using biophysical, biochemical, virology and structural biology techniques.

While studying for her Ph.D. at Wayne State University, she defined atomic resolution structural features in clinical drug targets using X-ray crystallography and computational molecular modeling, and applied structure-activity relationships (SAR) to design protease inhibitors that restore efficacy against multi-drug resistant HIV-1 protease. As an undergraduate at Wayne State, Tamaria’s research helped to identify a link between the chaperone protein ATP12p and mitochondrial DNA stability by a detailed characterization of 24 novel yeast strains with genetic defects in ATP12 using biochemical and molecular biology methods.

Photo of Fangli Chen Fangli Chen

Dr. Fangli Chen is a partner in the Litigation Department and vice chair of the Life Sciences Patent Practice. She represents all types of companies in the biotech and pharmaceutical industries, and has deep scientific expertise and a strong business sense. Fangli effectively…

Dr. Fangli Chen is a partner in the Litigation Department and vice chair of the Life Sciences Patent Practice. She represents all types of companies in the biotech and pharmaceutical industries, and has deep scientific expertise and a strong business sense. Fangli effectively identifies and transforms technological developments into valuable intellectual property assets for her clients and specializes in the strategic development of complex IP portfolios for companies that align with their business goals.

Fangli’s practice also focuses on post-grant review before the USPTO, oppositions, pre-litigation and litigation strategy, due diligence investigations, freedom-to-operate, non-infringement and invalidity analysis, licensing and other IP matters in connection with commercial transactions. She handles a variety of technology areas including biochemistry, molecular and cell biology, immunotherapy, enzyme replacement therapy, messenger RNA therapy, gene therapy, vaccines, bioinformatics, and small molecule compound drugs.

Fangli also has a wealth of experience in the following areas:

  • Post-grant challenges: representing clients in inter partes review interference and various foreign opposition proceedings.
  • Technology transactions & licensing: advising clients on matters relating to technology or material transfer, licensing and research collaborations.
  • Investment or acquisition counsel: assisting investors in assessing the technology and intellectual property assets and risks for potential target investments and counseling companies on intellectual property matters in connection with public offering or acquisition.

Fangli has been repeatedly noted for her top-tier work by industry publications, including being listed as a World’s Leading Patent Practitioner by IAM Patent 1000 and recognized as one of the Top 250 Women in IP nationwide by Managing Intellectual Property. In 2019, she was named Patent Strategy & Management Attorney of the Year in Massachusetts by LMG Life Sciences. She has also been recognized by Best Lawyers in AmericaClient Choice, Legal 500Massachusetts Lawyers Weekly and Massachusetts Super Lawyers. Prior to joining Proskauer, Fangli was a partner at a leading Boston law firm.