Theodore J. Chiacchio


Mr. Chiacchio has amassed over 15 years of experience litigating high-stakes, complex, federal civil cases.

Mr. Chiacchio has extensive experience in all phases of patent litigation, including, for example, preparing Markman briefs, taking and defending the depositions of inventors and other key fact witnesses as well as expert witnesses, preparing dispositive motions, preparing motions in limine, preparing all manner of post-trial submissions, and preparing opening, responsive, and reply appeal briefs filed with the U.S. Court of Appeals for the Federal Circuit. Mr. Chiacchio has also actively participated in Markman hearings and oral argument before the Federal Circuit. Further, Mr. Chiacchio has been integrally involved in a number of trials before U.S. district courts throughout the country, including with respect to direct and cross-examination of witnesses and opening and closing arguments.

Complementing his patent litigation experience, Mr. Chiacchio also has substantial experience with other types of civil litigation, including copyright infringement, a range of other business torts, employment discrimination, and white collar civil enforcement matters.

In addition to his litigation experience, Mr. Chiacchio is a USPTO-registered patent attorney and has spent a considerable portion of his career preparing Opinions of Counsel regarding patent infringement/non-infringement, patent validity/invalidity, and patent enforceability/unenforceability matters. Mr. Chiacchio also has substantial experience preparing Freedom to Operate Opinions. More generally, Mr. Chiacchio has counseled clients regarding a range of patent matters. Mr. Chiacchio’s patent law experience spans a range of technologies, including mechanical, the Life Sciences, chemical, telecommunications, and automotive.

Mr. Chiacchio earned his Bachelor of Arts degree (Biology, French) from Bucknell University in 1999 and his Juris Doctor degree from Cornell University Law School in 2002. Prior to joining Spence PC, Mr. Chiacchio served as an associate at Kenyon & Kenyon (now part of Andrews Kurth Kenyon) and, most recently, practiced for just short of a decade at a top tier patent litigation boutique in Chicago, IL.


  • J.D., Cornell University Law School, 2002
  • B.A., Bucknell University (Biology, French), 1999


  • Bar of New York
  • Bar of New Jersey
  • U.S. Patent and Trademark Office
  • United States Court of Appeals for the Federal Circuit
  • U.S. District Court for the District of Colorado
  • U.S. District Court for the Western District of Michigan

Publications and Speaking Engagements

Representative Experience

  • Represented generic drug manufacturer in defending against allegations of infringement of patent directed to a pseudopolymorph of the anti-HIV drug darunavir and compositions comprising darunavir, patent directed to a process for synthesizing darunavir, and patent directed to a process for synthesizing a key intermediate in the synthetic pathway for preparing darunavir.
  • Represented plaintiff in action alleging misappropriation of technical know-how and unjust enrichment in action to correct inventorship and re-assign patent directed to PEGylated arginine deaminase enzyme.
  • Represented medical device manufacturer in defending against allegations of infringement of patent directed to ocular surgical methods involving the use of small-gauge instruments to conduct vitrectomy procedures.
  • Represented patent-holder brand-name drug company in action alleging infringement of patent directed to a method of using ofloxacin to treat otopathy.
  • Represented patent holder before the European Patent Office in responding to Opposition to European patents directed to the anti-hemophelia biopharmaceutical rFVIII (blood-clotting protein) and pharmaceutical compositions containing rFVIII.
  • Represented patent challenger in Inter Partes Review proceeding before the U.S. Patent and Trademark Office’s Patent Trial and Appeal Board challenging the validity of patent directed to ethanolate form of the anti-HIV drug darunavir.
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