David P. Halstead, Ph.D.

Partner, Co-Chair, Intellectual Property Department, Registered Patent Attorney - Boston

David Halstead
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dhalstead@foleyhoag.com Download vCard

David Halstead is a partner in the firm's Intellectual Property Department. David works with clients in the biotechnology, chemical, and pharmaceutical industries on a wide range of intellectual property issues. He assists clients with obtaining robust and enforceable patents and navigating the existing patent landscape. Using his experience working with patents and applications in many foreign countries, David also helps clients devise effective global patent strategies designed to satisfy the idiosyncratic requirements of foreign patent offices.

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  • Harvard Law School, J.D., 2002
  • Harvard University, Ph.D. in Organic Chemistry, 1999
  • Pennsylvania State University, B.S. in Chemistry, summa cum laude, 1993

Representative Experience

  • Represented Proteolix, Inc. on intellectual property matters from their inception until their acquisition in 2009 by Onyx Pharmaceuticals for $276M in cash and up to $575M of additional performance-based payments. In addition to drafting and prosecuting the extensive, global patent portfolio that protected Proteolix’s key products, including the drug now known as carfilzomib (Kyprolis®), David also helped Proteolix navigate due diligence with various potential investors, partners, and acquirors.
  • Represents public biotech companies on a variety of intellectual property matters, drafting and prosecuting a broad patent portfolio covering diverse biotech and pharmaceutical technologies, including overseeing various successful European and Australian oppositions, managing relationships with collaborators, obtaining creative reach-through claims in both the US and Europe, and successfully defending these claims in a European opposition.
  • Represents global pharmaceutical companies, regularly advising them on business-critical issues from identifying and overcoming potential freedom-to-operate issues for biotech, pharmaceutical and consumer health product candidates to the handling of double-patenting issues with minimum impact on exclusivity expiration. In one exemplary project, David advised on the complex interplay of FDA labeling requirements, patent exhaustion, and inducement of patent infringement.
  • Represents publicly-held companies that develop drug delivery technologies, advising on strategies for navigating competitor patents while simultaneously structuring patent portfolios to maximize exclusive market space and gain leverage in potential licensing negotiations.
  • Represents investors in life science companies, helping them understand the patent portfolios that protect the value of their investments and analyze complex intellectual property disputes such as European oppositions & interferences.


  • Named Best Lawyers’ Boston Biotechnology Law Lawyer of the Year (2015)
  • Listed in The Best Lawyers in America, Biotechnology and Life Sciences Practice 


  • Boston Bar Association
  • Massachusetts Bar Association
  • American Chemical Society
  • Boston Patent Law Association
  • Board of Directors, Boston Early Music Festival
  • President, Board of Trustees, Musica Sacra
  • Co-chair, Life Sciences Committee of the Boston Bar Association's Intellectual Property Section (2007-2009)
  • “Advanced Topics in Double Patenting: A Webinar for Patent Prosecutors and Litigators,” Foley Hoag webinar (December 3, 2014)
  • "Bioequivalence and the 'Same Active Ingredient' vis-à-vis Patentability," American Conference Institute's Hatch-Waxman Boot Camp (July 20, 2010)
  • "Beyond Business Methods: Assessing the Impact of Bilski on Life Sciences Inventions," Boston Bar Association (June 1, 2009)
  • Panelist, "Written Description Guidelines for Patents Revisited," Boston Bar Association and Boston Patent Law Association (September 30, 2008)
  • "Master Class on Drafting Successful Patent Applications for Biotechnology Related Inventions," ACI Biotech Patent Conference (September 17, 2008)
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Bar Admissions

  • Massachusetts

Court Admissions

  • U.S. Patent & Trademark Office (Agency)