Karen Mangasarian, Ph.D.
Partner
Dr. Karen Mangasarian is a partner at Leason Ellis and a member of the Patent Practice Group. She counsels life sciences clients on all aspects of intellectual property. She has extensive experience in managing worldwide patent portfolios, and developing patent life cycle and competitive patent strategies.
Karen advises on patent landscapes, validity, patentability, non-infringement, and freedom-to-operate analyses, and performs IP due diligence in the context of transactions including license agreements, joint ventures, collaborations, and mergers and acquisitions. She has worked across a wide range of technologies, including small molecule pharmaceuticals, pharmaceutical formulations, antibodies, protein therapeutics, gene therapy, CRISPR technologies, and diagnostic and therapeutic methods in molecular and cellular biology, immunology, microbiology, biochemistry, genomics, and computational biology.
Karen also has extensive experience in contentious patent matters, including interferences, reexaminations, oppositions, and litigation.
- New York Law School, J.D., magna cum laude, 2000
- University of Wisconsin-Madison, Pharmacology, Ph.D., 1992
- University of Wisconsin-Madison, B.S., Biochemistry, 1984
- New York
- Registered Patent Attorney: U.S. Patent and Trademark Office
- S. District Court for the Southern District of New York
- S. District Court for the Eastern District of New York
- S. Court of Appeals for the Federal Circuit
- Haley Guiliano LLP, Partner, 2019-2025
- Foley & Lardner LLP, Partner, 2017-2019
- Ropes & Gray LLP, Associate/Partner, 2005-2017
- Fish & Neave, Patent Agent/Associate, 1997-2004
- New York Intellectual Property Law Association, Member
- Intellectual Property Owners Association (IPO)
- Pharmaceutical & Biotechnology Issues Committee
- LMG Life Sciences Patent Strategy Practitioner of the Year, New York, 2025
- Life Sciences Patent Network Awards Patent Prosecution Practitioner of the Year, 2025
- IAM Patent 1000, 2014-2019, 2022-2025
- Managing IP Patent Star, 2021, 2023-2025
- Best Lawyers, 2023,-2025
- NY Super Lawyers, 2021-2025
- WIPR Leaders, 2024
- Co-author, “Life Sciences Transactions – Look Before You Leap,” Life Sciences Intellectual Property Review (2016)
- Co-author, “Lessons Learned from IPR Proceedings in the Life Sciences,” BNA Patent, Trademark & Copyright Journal (2015)
- Panelist, “Patent Prosecution Basics,” PLI Understanding Patent Law (May 22, 2019)
- Panelist, “Patent Law Basics,” Accelerating Bioventure Innovation, Weill Cornell University (October 2, 2018)
- Panelist, “Patent Prosecution Basics,” PLI Understanding Patent Law (May 24, 2018)
- Panelist, “Patent Prosecution Basics,” PLI Understanding Patent Law (June 2017)
- Panelist, “Patent Prosecution Basics,” PLI Understanding Patent Law (June 28, 2016)
- Panelist, “Patent Prosecution Basics,” PLI Understanding Patent Law (June 30, 2015)
- Panelist, “Update on Patent Term Extensions in the United States,” C5’s 14th Pharmaceutical Patent Term Extensions Forum, Munich, Germany (June 22-23, 2015)
- Panelist, “Post-Grant Review and Inter Partes Review Boot Camp,” ACI Paragraph IV Disputes Master Symposium, Chicago, IL (October 2, 2013)
- Panelist, “Patent Prosecution Basics,” PLI Understanding Patent Law (July 29, 2012)
- Panelist, “Considerations For Post-KSR Biotech/Pharma Patent Prosecution,” American Conference Institute, New York, NY (February 25-26, 2008)
- Panelist, “International Considerations In Freedom To Operate: U.S. and E.U. Perspectives,” American Conference Institute, San Francisco, CA (October 24-25, 2005)
- Panelist, “International Concerns In Freedom To Operate Determinations,” American Conference Institute, New York, NY (March 14-15, 2005)
- Represented an academic institution in an interference relating to diagnostic methods for detecting cancer associated mutations.
- Represented a biotechnology company in an interference relating to beta interferon.
- Represented a biopharmaceutical company in an interference relating to a G protein-coupled receptor.
- Represented a biotechnology company in an interference relating to tumor necrosis factor ligand.
- Represented a biotechnology company in an interference relating to an osteogenic protein.
- Represented a biotechnology company in an interference relating to transgenic fibrinogen.
- Represented a biopharmaceutical company in challenging a patent relating to a method for screening for specific GPCRs.
- Represented a biotechnology company in defending its patent relating to heterologous expression of polypeptides in filamentous fungi.
- Represented an academic hospital in an unjust enrichment and unfair trade practices case involving patents directed to a method for treating age-related macular degeneration.
- Represented an academic hospital in a patent infringement litigation involving patents directed to a method for treating age-related macular degeneration.