US patent litigation has been steadily declining since 2015, according to Lex Machina:

Likewise, IPR and PGR filings at the USPTO’s PTAB also are in steady decline:

Though some years show small upticks, the trend is clear. In our experience, an array of changes to the patent system, mostly enacted between 2010 and 2015, have dramatically changed US patent litigation. In the past, patent litigation seemed to follow a traditional bell curve, with a small number of nuisance cases, a small number of mega cases, and lots of cases in the middle. Nowadays, the middle seems to have been gutted, and most patent lawsuits seem to be nuisance filings, with a small number of mega cases. The nuisance cases usually settle quickly, or are mooted by an IPR. Mega cases can last for many, many years.

The number of IPR filings has fallen as a direct consequence of the decline in lawsuits, but it also reflects that the PTAB is no longer as anti-patent as in its early days. One of the most important changes in IPR practice has been the shift in how patent claims are interpreted. The PTAB at its outset was interpreting patent claims broadly, using the Broadest Reasonable Interpretation standard (BRI). Eventually, the PTAB adopted the same claim construction approach as the courts, which usually results in a narrower claim construction. As a consequence, the PTAB became a less attractive venue for attacking the validity of a patent than a district court.

A recent decision by the PTAB demonstrates why a district court can be a better venue for a defendant to challenge patent validity. The case, Cambridge Mobile Telematics, Inc. v. Sfara, Inc., IPR2024-00952, Paper 12 (P.T.A.B. Dec. 13, 2024), concerned U.S. Patent No. 8,989,952 B2, directed to determining whether a vehicle has crashed using a cell phone in the car. The ‘952 patent claims priority to 2012 and is owned by Sfara. Cambridge Mobile Telematics (CMT) petition for IPR after Sfara sued CMT for infringement.

In its petition, CMT addressed claim construction, as it must. The PTAB dismissed CMT’s petition because CMT argued a different claim construction in the IPR petition than it argued before the district court.

It seems that CMT was in a pickle with the IPR and claim construction. In the district court, CMT argued that the claims were invalid for indefinitness. More specifically, CMT argued to the district court that the claims included means-plus-function elements, but the patent lacked the required description of the means which performed the function. In contrast, before the PTAB, CMT argued that the claims did not need to be construed because all of the terms in the claims had their plain and ordinary meaning.  Because CMT did not explain why it presented inconsistent claim construction positions to the PTAB, the PTAB dismissed CMT’s petition for IPR.

Why the pickle? Why didn’t CMT do a better job explaining the situation to the PTAB? CMT’s counsel seem competent. The problem lies in some important differences between PTAB practice and district court practice. First, in IPRs the PTAB can only consider invalidity based upon prior art publications. In contrast, a district court can consider any basis for invalidity, such as lack of written description as was relevant in the case. In my experience, it can be a challenge to work around these kinds of restrictions. Second, the PTAB has strict limits on the number of words in a petition for IPR. Perhaps CMT’s counsel simply did not have enough word budget to adequately explain both its core invalidity position, plus explain how its claim construction arguments were different before the district court, and why it did not matter. Third, even if CMT wanted to present the same claim construction arguments to the PTAB and as the district court, the word count limitations might have made it imposssible because the PTAB has some tricky rules that can make claim construction arguments much longer than in a district court.

Although CMT lost the IPR, it retains the right to assert the same invalidity arguments to the district court because the statutory estoppel rules only apply to a final written decision (FWD) at the end of the IPR, but this case was dismissed at the petition stage.