The Generic Drug Industry Embraces a Faster, Cheaper Pathway for Challenging Patents

Appl Health Econ Health Policy. 2019 Feb;17(1):47-54. doi: 10.1007/s40258-018-0420-8.


Background: Most new brand-name drugs are protected by patents from generic competition, but these patents are occasionally granted in error. Invalidating such patents has traditionally been accomplished via court litigation by generic manufacturers, which is expensive and time consuming. In 2011, Congress created an administrative alternative to court litigation of patents, called inter partes review, intended to be much faster and less expensive.

Objective: To evaluate the use of inter partes review to challenge pharmaceutical patents, including the number of challenges, the number of associated drug products, and the extent to which challengers have been successful.

Methods: We obtained data pertaining to inter partes review proceedings, including identity of patent challenger, duration of proceedings, and outcome, from September 16, 2012 through April 24, 2017 from, and combined it with information about drug products and their associated patents, including patent type, contained in the US Food and Drug Administration's Orange Book.

Results: Generic drug manufacturers have embraced the new inter partes review process, succeeding in overturning all challenged claims in 43% of the patents they have targeted since 2011, and some challenged claims in an additional 8%. Inter partes review for drug patents has consistently been completed within 12 months, as required by statute. Successful challenges have been brought most frequently against drug patents covering new formulations or methods of use, rather than drug patents covering active ingredients.

Conclusion: In the pharmaceutical market, the inter partes review process can meaningfully contribute to ensuring that invalid patents do not block timely availability of generic drugs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Drug Industry / legislation & jurisprudence*
  • Drugs, Generic*
  • Humans
  • Legislation, Drug
  • Patents as Topic / legislation & jurisprudence*
  • United States


  • Drugs, Generic