The Overlap Between Patents Asserted in District Court and Challenged at the PTAB

The USPTO’s April 21, 2023 Advanced Notice of Proposed Rulemaking (ANPRM) (see here for details) brings to the fore of Patent Trial and Appeal Board (PTAB) policy discussions one overarching issue that has long been debated by the Board’s proponents and critics: whether such challenges are more often used as swords or shields.

Because some of the changes in that proposal could reshape the interplay between PTAB proceedings and district court litigation, it may be helpful for stakeholders on all sides of the debate to start from a common factual understanding of the overlap between the patents asserted in district court and those challenged in the most common PTAB proceeding (by far), the inter partes review (IPR).

RPX data show that a relatively small share of the patents collectively asserted in district court have been challenged before the PTAB, an overlap shown in the Venn diagram below. Of the roughly 25,010 patents that have been the subject of complaints filed in district court from September 16, 2011 through May 26, 2022, just under 7,020 of those patents, or 28%, have been hit with subsequent petitions for IPR. (This time period accounts for the one-year window within which defendants may file IPRs over patents asserted against them, and therefore includes lawsuits for which IPRs could have been filed starting when IPRs first became available on September 16, 2012 and as recently as May 26, 2023.) Put another way, nearly three quarters of the patents asserted in district court cases (72%) do not see a subsequent IPR petition.

Conversely, the data further reveal that district court litigation has remained a key driver of PTAB proceedings, as 79% of the patents challenged in IPR petitions (out of a total of around 8,860 patents) were first asserted in district court.

Overlap Between Patents Litigated in District Court and Those with IPRs

Note: Excludes declaratory judgment (DJ) actions and biopharma litigation.

Taking a step further, we divide the universe of challenged patents between those owned by operating companies (OpCos) and those owned by non-practicing entities (NPEs) to ascertain whether there are distinctions in the frequency at which OpCo-asserted and NPE-asserted patents are challenged.

A smaller degree of overlap is evident when we limit the analysis to patents asserted by operating company plaintiffs in district court: 24% of those patents were subsequently challenged in IPR proceedings in which operating companies remained the patent holders (or just under 3,610 of the more than 15,030 patents such plaintiffs have asserted in district court, minus biopharma litigation). On the flipside, 70% of the patents challenged in IPR proceedings with operating company patent holders were first asserted by operating companies in district court (out of approximately 5,130 patents challenged).

Overlap Between Patents Litigated by Operating Companies in District Court and Those with IPRs

Note: Excludes DJ actions and biopharma litigation.

In contrast, limiting the analysis to patents asserted by NPEs results in greater overlap compared to the overall number (i.e., compared to the data with no plaintiff-type filter): Just under one third of the patents litigated by NPEs (32%) were then challenged in IPR proceedings with NPE patent holders (around 3,300 out of just over 10,170 total asserted patents). Additionally, 88% of the patents challenged in IPR proceedings with NPE patent holders were first asserted by NPEs in district court (out of about 3,750 in total).

Overlap Between Patents Litigated by NPEs in District Court and Those with IPRs

Note: Excludes DJ actions and biopharma litigation.