Patexia Insight 255: District Court U.S. Patent Litigation Grows in 2025

Over the past six years, patent enforcement in the United States has been constantly shifting. Court decisions, changes in PTAB practice, and the realities of global manufacturing have all influenced how patent disputes are filed and defended. District courts, the PTAB, and the International Trade Commission have each played a role in that evolution.

In 2025, U.S. district courts handled more patent cases than in the recent past, while PTAB and ITC Section 337 investigations remained an important part of the overall enforcement picture. Taken together, these three venues provide a useful way to see how patent litigation has developed since 2020 and where things stood at the close of 2025.

The chart above shows the total number of patent cases filed in U.S. district courts over the past six years. After relatively steady activity from 2020 through 2022, filings dropped sharply in 2023 to 3,108 cases. This was followed by a recovery in 2024, and in 2025, filings rose further to 4,426 cases, the highest level recorded in the six-year period.

Several factors may have contributed to these shifts over the six-year period. Changes in venue rules, evolving case strategies, and fluctuations in industry activity can all influence when and where patent disputes are filed. For readers looking for a deeper understanding, many questions remain: Which districts saw the most filings? Which companies were the most active? Which law firms and attorneys experienced the largest increases in case involvement? All of these questions, and more, will be addressed in our upcoming Patent Litigation Intelligence Report, set to publish in two weeks. The report provides detailed analysis across federal courts, highlighting trends in filings, outcomes, and the professionals dominating the U.S. patent litigation market.

The rise in district court filings tells only part of the story. For many defendants, patent litigation does not stop at the courthouse door. Administrative challenges before the Patent Trial and Appeal Board remain a central part of how companies respond to infringement claims, particularly in cases involving high-value patents and repeat litigants. Looking at PTAB activity alongside court filings helps clarify how often parties are choosing to challenge patents at the agency level and how that behavior has changed over the past several years.

As seen above, IPR filings have generally remained steady, ranging from 1,157 cases in 2023 to 1,443 in 2020, with slight year-to-year fluctuations. PGR proceedings have been fewer in number but saw a modest increase in 2025 to 74 filings. Whether the recent rise in district court litigation will translate into more PTAB challenges in the coming months remains to be seen.

The chart above shows the number of Section 337 investigations filed at the International Trade Commission over the past six years. Filings have generally stayed within a moderate range, peaking at 79 cases in 2022 before dropping to 50 in 2023. Activity rebounded somewhat in 2024 to 72 filings, followed by 66 cases in 2025.

While the ITC handles far fewer cases than district courts or the PTAB, it remains a key venue for patent owners seeking exclusion orders or other high-stakes remedies, particularly in disputes involving imported products. The data suggest a relatively stable level of activity, with minor year-to-year fluctuations reflecting the strategic use of the forum by both plaintiffs and defendants.

Looking Ahead

Across district courts, the PTAB, and the ITC, 2025 shows a patent enforcement landscape that remains busy and strategically complex. While activity differs by forum, the year highlights where disputes are most concentrated and which venues see the heaviest use. For those looking for a closer look at the numbers, including the most active and highest-performing companies, law firms, and attorneys, our upcoming Intelligence Reports will provide a detailed, data-driven analysis across all major U.S. patent forums.