Print PDF

Leslie A. McDonell
+1 617 646 1650

Two Seaport Lane
Boston, MA 02210-2001

+1 617 646 1600
Fax +1 617 646 1666

Bar and Court Admissions

  • California
  • District of Columbia
  • Massachusetts
  • New York
  • U.S. Patent and Trademark Office


  • University of San Diego School of Law
    J.D., 1988
  • Eastern Virginia Medical School
    Biomedical Sciences Program, 1983-1984
  • Virginia Polytechnic Institute & State University
    B.S., Microbiology, 1981

Leslie A. McDonell


Leslie McDonell, managing partner of the firm's Boston office, provides strategic counseling to both startups and larger companies on the procurement and protection of intellectual property in the pharmaceutical and biotechnology industries. She coordinates worldwide patent portfolio strategies, evaluates and analyzes competitors' patent positions around the world, and advises and renders opinions on issues of patentability, inventorship, validity, claim scope, infringement, and freedom-to-operate. Ms. McDonell has extensive experience in conducting due diligence investigations and preparing companies to be the target of a due diligence, pre-litigation analyses, and offensive and defensive post-grant proceedings.

Ms. McDonell has represented clients before the U.S. Patent and Trademark Office (USPTO) in patent appeals, interferences, reissues, reexaminations, and inter partes reviews (IPRs). Her U.S. litigation experience includes representation of both plaintiffs and defendants in biotechnology and pharmaceutical cases.

In addition, she has prepared and prosecuted patent applications throughout the world and has been involved in opposition and appeal proceedings in numerous countries and at the European Patent Office (EPO). She has patent experience in the fields of immunology, virology, molecular and cellular biology, and small molecule and natural product pharmaceuticals, including antibody technologies, RNA-based gene therapies, vaccines and diagnostics, inflammatory and autoimmune disease therapies, metabolic disorder therapies, pluripotent and stem cell therapies, and cancer therapies.

Ms. McDonell is a frequent guest speaker on the affirmative use of and best defense to inter partes reexamination and IPRs. She has extensively studied and is a guest speaker on the impact of the America Invents Act (AIA) on the biotechnology and pharmaceutical industries.


  • Chiron v. Eli Lilly and Vertex Pharmaceuticals (N.D. Cal.) Represented Eli Lilly against charges of infringement in the development of an HCV small molecule therapeutic, resulting in a favorable settlement.
  • Schering Corporations v. American Home Products Corp. (D.N.J.) Represented American Home Products/Wyeth in litigation involving loratadine products.
  • Represented Biogen against Medeva for infringement of patents covering hepatitis B antigens in the U.K. Patent Court, Court of Appeals, and House of Lords. Also assisted in the successful defense against opposition of these same patents at the EPO's Technical Board of Appeals.
  • Represented Institut Pasteur in a series of inter partes reexaminations of patents involving homologous recombination technology.
  • Successfully appealed USPTO decisions on key patent applications for Syntonix Pharmaceuticals and University of Edinburgh.
  • Mayo v. Prometheus (S. Ct.). Coauthored amicus brief to U.S. Supreme Court on behalf of the American Intellectual Property Law Association.
  • Represented Biogen, Genetics Institute, Wyeth, and Creative BioMolecules in interferences involving molecular biology inventions.
  • Served as judicial extern to the Honorable Judith N. Keep of the S.D. California, 1988.

Professional Recognition

  • Recognized as a leader in the field of intellectual property law by Chambers USA, 2015-2017.
  • Recognized by The Legal 500 U.S. for patent prosecution, re-examinations, and post-grant proceedings, 2015, 2016; and for patent portfolio management and licensing, 2016.
  • Recognized as an "IP Star—Top 250 Women in IP," 2013, 2016, 2017; and as an "IP Star" in Massachusetts by Managing Intellectual Property, 2013-2017.
  • Recognized by World IP Review as a WIPR Leader for patents in the United States, 2016, 2017.
  • Listed in LMG Life Sciences as an Intellectual Property: Life Sciences Star, 2012-2016.
  • Recognized as a leader in patent counseling in the field of life sciences in the U.S. by Practical Law Company's Which Lawyer, 2010.
  • Recognized as a Massachusetts "Super Lawyer" in Intellectual Property, Super Lawyers published by Thomson Reuters, 2007, 2014-2016; and a "Rising Star," 2005.

Professional Activities

  • BIO Intellectual Property Counsels' Committee
  • American Intellectual Property Law Association
  • American Bar Association (subcommittee chair, Intellectual Property Law Committee)
  • Boston Bar Association (subcommittee chair, Intellectual Property Section)
  • Boston Patent Law Association (co-chair, Amicus Committee)
  • Massachusetts Biotechnology Council

Select Publications