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William Zimmerman

Having served as lead counsel in over 100 pharmaceutical litigations, including cases involving “blockbuster” drugs like Lipitor and Nexium, William R. Zimmerman is widely recognized as one of the nation’s premier life science litigators.  As co-chair of both the firm’s Hatch-Waxman and Life Sciences Practice Groups, Bill oversees a diverse team of attorneys who have collectively litigated over 200 complex cases involving pharmaceutical products. 

Recognized as the “Hatch-Waxman Litigator of the Year,” Bill Zimmerman is well-versed in the Abbreviated New Drug Application process and the complexities Hatch-Waxman litigation.  He has been widely acknowledged for his expertise in pharmaceutical matters, being repeatedly named one of “The World’s Leading Patent Professionals” by IAM, a “Life Science Star” by LMG, an “IP Star” by Managing IP, and a “Washington D.C. Super Lawyer” by Super Lawyer’s Magazine.  He was previously named one of the top fifty intellectual property lawyers under the age of forty by IP Law & Business magazine.

Bill is the founding managing partner of the firm’s Washington, D.C. office.  Before joining the firm, he served as a law clerk to the Honorable Alvin A. Schall, Circuit Judge of the United States Court of Appeals for the Federal Circuit.


Harvard Law School, J.D., Member – Harvard Journal of Law & Technology, Member – Harvard Environmental Law Review
University of Notre Dame, B.S., Chemical Engineering, Tau Beta Pi – Engineering Honor Society
District of Columbia Bar
State Bar of California
Supreme Court of the United States
U.S. Court of Appeals for the Federal Circuit

Biological Manufacturing of Chemicals


Diagnostic Tools



Chemical, Industrial & Materials

Analytical Chemistry


Chemical Engineering

Organic Chemistry

Pharmaceutical Chemistry


Green Chemistry

Medical Devices & Procedures


Antibodies & Immunology

Biological Manufacturing of Chemicals


Biosimilars & Hatch-Waxman Litigation

Diagnostic Tools

Personalized Medicine

Research Tools & Reagents



Appellate Litigation
HatchWaxman Litigation
Infringement Risk 
Inter Partes Review (IPR)
Patent Litigation
Patent Strategy & Prosecution
Patent Trial & Appeal Board (PTAB) Litigation
PostGrant Review (PGR)
PTAB Overview
Tech Transactions

Bill has received multiple awards and has been honored in both national and international forums for his legal accomplishments:

  • Recognized as a “Washington D.C. Super Lawyer” by Super Lawyers magazine for his intellectual property litigation practice (2015 – 2023)
  • Ranked amongst top ten for Top 100 Most Active ANDA Attorneys Representing
    Defendants and 12th for Best Performing ANDA Attorneys Representing Defendants by Patexia Insight’s 2021 ANDA Litigation Intelligence Report
  • Selected by peers for inclusion in The Best Lawyers in America® for his outstanding work in Intellectual Property Litigation (2022 – 2024)
  • Selected by The Legal 500 “United States” for Patent Litigation (2018-2023) and Patent Prosecution (2018 – 2021)
  • Recognized as a Patent Star in Managing IP’s “IP Stars” Guide for his outstanding intellectual property legal work (2014 – 2023)
  • Named Top Patent Challenger Attorney 2020 by Docket Navigator
  • Named a “Life Science Star” by Legal Media Group “LMG Life Sciences” (2012 – 2018 and 2022). In 2022, Bill was recognized in the areas of Patent Strategy & Management and Hatch-Waxman Litigation. In 2018, Bill was recognized in the areas of Patent Litigation and Hatch-Waxman Litigation. A client praised Bill as a “highly experienced litigator, who can always be relied on to give solid, practical advice”. In 2017, Bill was commended by peers as “one of the very excellent lawyers on the generic side”. In 2016, he was recognized for his work in cardiovascular drugs, drug formulations, transdermals, biologics, biosimilars, combination products, allergenics, antibiotics, vaccines, and dental devices. Bill was also noted for helping client Ranbaxy receive a favorable decision, allowing the company to market a generic version of Lipitor, the world’s best-selling drug.
  • Named one of the “World’s Leading Patent Professionals” for litigation in the Patent 1000 guide by Intellectual Asset Management (IAM) magazine (2013 – 2018; 2022 – 2023). In the 2018 guide, Bill was recognized for being “well versed in the intracacies of the ANDA process” and commended for his “rare finesse” litgating under the Hatch-Waxman Act.
  • Nominated by the Managing IP (MIP) Americas Awards 2018 for “Outstanding Litigator – D.C.”
  • Named in Who’s Who Legal’s 2017 edition of the international “Who’s Who Legal: Patents” list
  • Named “Hatch-Waxman Litigator of the Year – Generic” in the 2016 LMG Life Sciences Awards by Legal Media Group (LMG)
  • Named in the Intellectual Asset Management (IAM) Life Sciences 250 – The World’s Leading Life Sciences Patent Litigators (2010)
  • Named one of the top 50 intellectual property lawyers under the age of 40 by IP Law & Business magazine (2008)
  • American Intellectual Property Law Association (AIPLA)
  • Federal Circuit Bar Association
  • American Bar Association (ABA)
  • Federal Circuit Historical Society (Treasurer; Executive Board)
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