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Duane A. Stewart, III.

Duane A. Stewart, III.


Pittsburgh, PA

How Duane Helps Clients

Duane integrates complex science and legal matters at a high level. He specializes in explaining complex intellectual property law concepts in an accessible way. Duane is the co-chair of the firm’s Chemical Practice Group.

Duane focuses on patent prosecution, portfolio management and litigation; trademark procurement and portfolio management; and analysis and due diligence for transactions including intellectual property. He also has experience with copyright and trade secret law.

His patent practice includes preparation and prosecution of domestic and foreign utility and design patents in the pharmaceuticals, battery, fragrance, home products, refrigerant, and biotechnology fields. Duane has obtained multiple foreign and domestic patents in industrial water purification. He has significant experience managing international patent portfolios, having made and managed filings in more than 30 jurisdictions. He has taken an active role in priority determinations in patent interferences and has participated in litigations involving allegations of patent infringement and copyright infringement. Duane’s particular patent focus is on use of PCT filings to obtain wide territorial coverage while satisfying the applicant’s business goals.

Duane’s trademark practice includes all phases of procurement and enforcement, including knockout searches, clearance opinions, watches, filings and oppositions. He has supervised foreign trademark filing both directly and through the Madrid Protocol, and he has filed foreign-origin applications in the United States.

Before joining Buchanan, served for two years as a judicial law clerk with the late Honorable David A. Katz of the United States District Court for the Northern District of Ohio in Toledo, Ohio.

What Clients Can Expect

Duane addresses client's IP issues with effective strategy and pragmatic advice. He keeps the client's business goals top of mind and makes sure that clients know that their matters have his attention.

Outside the Office

When he's not at work, Duane enjoys spending time with his wife and their two children. One of his favorite activities is family game night. Duane enjoys Euro-style board games, which emphasize strategy and tactics over luck. He is also a member of the professional table soccer tour.

For the client, every legal question is also a business question.

Proof Points

  • The Best Lawyers in America® consistently since 2018 under the Litigation - Intellectual Property and Trademark Law categories.
  • Managing Intellectual Property, Patent Star (2014-2017, 2020, 2023), Trademark Star (2016-2017), IP Star (2014-2022).
  • IAM Patent 1000 (2016, 2018-2021).
  • Pennsylvania Super Lawyers® Rising Stars list (2013).
  • BTI Client Service All-Star (2011).
  • Former adjunct lecturer at the West Virginia University College of Law.
  • Delivered CLE programs as a lecturer for the Pennsylvania Bar Institute.
  • Prepared and prosecuted provisional, utility and PCT patent applications in the bioproducts, pharmaceuticals, energy, water purification, building supplies, aroma and beauty fields for universities and for businesses ranging in size from startup companies to Fortune 500 companies.
  • Prepared freedom to operate opinions for corporations in the pharmaceutical, biotechnology, fragrance and beauty industries.
  • Participated in patent litigation and interference proceedings in the medical, personal care, automotive and consumer products industries.
  • Prepared and evaluated confidentiality and licensing agreements.
  • Managed trademark portfolios in the bath, bedding, fashion and energy industries.
  • Procured and managed the trademark portfolio of an Internet social networking and e-commerce website ranked in the top 1000 websites worldwide by traffic.
  • Policed unauthorized use of client intellectual property through DMCA takedown requests, cease and desist letters and UDRP actions.
  • Resolved trademark oppositions and threatened oppositions through coexistence agreements and sale-and-license-back agreements.
  • Coordinated trademark filing and prosecution worldwide, with multiple filings in all continents but Antarctica.
  • Reviewed and evaluated intellectual property estates prior to acquisition of those estates, followed by management of the international assignment process after acquisition.