Mr. Papacostas is an intellectual property attorney with substantial litigation experience in federal courts. He primarily focuses his practice on patent litigation in federal courts and post-grant proceedings before the patent office. He also has experience with patent-related antitrust issues, trademark litigation, counseling, and proceedings before the Trademark Office, and general intellectual property due diligence and counseling, including both domestic and international intellectual property matters. Mr. Papacostas has argued matters in federal district court and before the Court of Appeals for the Federal Circuit, and has represented clients in bench and jury trials as well as arbitrations in federal courts. Simeon has represented clients across a wide range of industries, including medical device manufacturing, pharmaceutical, biotechnology, drilling and oilfield services, computer hardware and software, consumer products, video game development and military contracting.

Simeon is also active in pro bono work, and has represented clients in matters involving international human rights, immigration law, animal rights, and various trademark and copyright issues.