Kathleen Duffy

I'll research this attorney before drafting.

Kathleen Duffy (now practicing as Kathleen Duffy Lichtenstein) — Arnold & Porter Kaye Scholer LLP

Specialty / focus. Her tracked patent work sits in the footwear and apparel technology space — specifically Nike's knit-upper ("Flyknit"-type) patent portfolio, covering knit textile elements, unitary knit construction, and methods of manufacturing shoe uppers. Her firm biography describes a broader IP litigation practice concentrated on "protection and enforcement of extensive IP portfolios owned by leaders in the apparel and footwear industry," with additional listed experience for a medical device company in patent infringement and unfair competition matters. The registered patent filings and TTAB/PTAB dockets tying her name to the practice are predominantly footwear and consumer-brand related; she also maintains a substantial trademark and anti-counterfeiting docket for apparel clients. There is no sourced indication of Wi-Fi/standards, pharmaceutical, or heavy software experience. (Sources: Arnold & Porter attorney profile; Nike v. New Balance, D. Mass. No. 1:23-cv-12666.)

Side preference. Her tracked appearances are 1-0 on the plaintiff side, and the public record is consistent with that: Nike, Inc. as plaintiff in the New Balance litigation and as opposer/applicant in multiple TTAB proceedings, plus Nike as plaintiff in Schedule "A" anti-counterfeiting actions across the Northern District of Illinois and Eastern District of Missouri. This is brand-owner-side enforcement work, not NPE/PAE prosecution. The one tracked data point is too thin to characterize her as a plaintiff-only practitioner generally, but nothing in the sourced record shows her defending an accused infringer in a patent case.

Firm context. Arnold & Porter Kaye Scholer is the only firm associated with her tracked appearance. Her TTAB filings from 2021 to the present list the firm's Washington, D.C. and Chicago offices, and more recent docket entries list Arnold & Porter's D.C. and Chicago addresses. No prior-firm history is verifiable from public sources.

Notable cases. Nike, Inc. v. New Balance Athletics, Inc. (D. Mass. 1:23-cv-12666, filed Nov. 6, 2023) is the marquee matter. Nike asserted nine footwear patents; New Balance moved to dismiss claims on the '350, '511, and '758 patents, arguing Nike's infringement theory contradicted the Federal Circuit's construction in Nike, Inc. v. Adidas AG, 812 F.3d 1346 (Fed. Cir. 2016) ("flat knit edges" exclude knit-to-cut elements). The court denied that motion on August 13, 2024. The case was stayed in June 2025 pending IPRs on six of the nine patents; in August 2025 the parties stipulated to dismiss claims and defenses on the '484 patent, and the case remains stayed pending Nike's appeal of a PTAB final written decision holding the '749 patent unpatentable. She appeared pro hac vice for Nike. Note the important caveat: the IPRs in that case were instituted on petitions by third parties (including Skechers and lululemon), so the invalidity results are not attributable to her. Her other visible work — TTAB oppositions and Schedule "A" counterfeit actions for Nike — is enforcement-heavy and rarely produces published outcomes.

PTAB / IPR experience. Her firm bio cites handling "complex discovery disputes before the TTAB and PTAB," and her name appears on TTAB filings (e.g., oppositions involving NIKETO and San Antonio Shoe). I found no sourced evidence that she personally authored or argued an IPR/PGR petition or appeared at a PTAB oral hearing, so I would not characterize her as a regular IPR practitioner on the current record.

Bar / education. Admitted in the District of Columbia and New York; also admitted to the S.D.N.Y. and N.D. Ill. J.D. (IP law), American University Washington College of Law, 2020 (cum laude); M.B.A., American University Kogod School of Business, 2020 (cum laude); B.A. in Biology and Political Science, Bucknell University, 2015.

One data note: the tracked case list records her role as "Counsel," while Arnold & Porter's current bio lists her as Senior Associate and some dockets use the surname "Duffy Lichtenstein." These appear to be the same attorney, but the title discrepancy should be confirmed before filing.