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Paul A. Ainsworth


Paul A. Ainsworth

Paul A. Ainsworth, a director in Sterne Kessler's Trial & Appellate Practice Group, is an experienced intellectual property trial attorney with a practice focused on patent and trade secret disputes in federal district courts, at the U.S. International Trade Commission (ITC), and before the United States Court of Appeals for the Federal Circuit. Paul also regularly represents clients in proceedings before the Patent Trial and Appeal Board (PTAB). Paul's clients include leading companies in the pharmaceutical, biopharmaceutical, medical devices, chemical manufacturing, and consumer products industries.

Paul is particularly well-known for his work in the firm’s award-winning Hatch-Waxman litigation practice. From pre-litigation strategy through trial, appeal, and/or settlement, he has led teams on more than twenty patent cases for both innovator and generic drug clients. Paul leverages his deep understanding of the IP, regulatory, and business dynamics unique to the pharmaceutical industry to assist his clients in achieving their business objectives.

Paul is also a leader in the firm’s high-profile ITC practice. Section 337 investigations have a well-earned reputation for being fast-paced, high stakes, and unforgiving. Paul has skillfully and successfully represented complainants and respondents in investigations involving their most important product markets.

Paul also has significant experience representing clients, particularly pharmaceutical, biotech, and software companies, in trade secret matters. With uncertainty growing around the ability of U.S. patent law to protect IP portfolios, clients turn to Paul for planning and executing effective trade secret strategies to safeguard what is often their most valuable asset.

Paul is a contributing author of Patent Office Litigation, Second Edition, published in 2017 by Thomson Reuters Westlaw. The book provides a fresh and comprehensive exploration of patent office litigation proceedings, including how the proceedings interact with other aspects of patent procurement and enforcement, while delivering practical analysis and advice. He is also a contributing author of Pre-ANDA Litigation: Strategies and Tactics for Developing a Drug Product and Patent Portfolio, Second Edition, published in 2018 by the American Bar Association, and ANDA Litigation: Strategies and Tactics for Pharmaceutical Patent Litigators, Third Edition, to be published in 2019 by the American Bar Association.

Paul began his legal career as a law clerk for the Honorable Sue L. Robinson, United States District Judge, District of Delaware. In addition to his patent litigation practice, he has also represented leading civil rights organizations on state and federal civil rights issues. In 2011, the National LGBT Bar Association named Paul as one of the “Best LGBT Lawyers Under 40” in recognition of both his accomplishments as an IP litigator and his contributions to the advancement of LGBT civil rights.

When not in the courtroom, Paul is most likely to be found hiking in the Allegheny Mountains with his dog, Rugby.


William & Mary Law School
Political Science
The George Washington University


  • U.S. District Court for the District of Delaware