Preparing an inter partes review is a team sport: case study two

It is legally and financially beneficial for a defendant in a patent infringement dispute to utilise the inter partes review process to attempt to invalidate asserted patent claims. Given the popularity of this process, the associated practice of law in petitioning these reviews before the PTAB has become fairly specialised. Industry focus, case selection and, of course, legal expertise and experience from one firm to the next play key factors. Often overlooked is the quality and methodology of obtaining the prior art that is central to any inter partes review argument. This article reviews Global Prior Art’s internal database of over 17,000 invalidity prior art cases addressed since the firm was created in 1982, including many thousands in which Global Prior Art supported subsequently filed inter partes review petitions, to pinpoint case studies that illustrate the impact of strong (and weak) prior art and the underlying methodologies used to obtain them. The learnings from these case studies – which will be presented over the next few weeks in the IAM weekly newsletter – can be instrumental in setting out strong arguments for inter partes reviews and, in turn, increasing an attorney’s likelihood of success.

Case study – Microsoft v Mimzi LLC

Mimzi LLC owns and asserts US Patent 9,128,981 (981 patent), entitled Phone Assisted Photographic Memory, which covers “recorded speech from a mobile electronic device to query a social network database, which outputs info to a user based on their location”. Further, the patent has 287 cited references and has been the focus of previous litigation involving various companies, including TripAdvisor (1-18-cv-01768 (DDE)), Foursquare Labs (1-18-cv-01767 (DDE)), HTC Corporation (1-19-cv-00274 (DDE)) and ASUSTek Computer Inc (1-19-cv-00273 (DDE)).

In Microsoft v Mimzi LLC, two references, which had not been identified in previous searches, were uncovered by Global Prior Art’s team and relied on for the inter partes review. The primary reference was US Patent 7,895,177 to Wu (177 patent), as well as the supporting reference US Patent Application Publication 20080153465 to Evermann.

In cases such as this, a keyword search will not work, as keyword strings usually flag a huge number of hits as all key terms are generic (eg, query/search, speech, location and weights). However, narrowing the keyword search means that critical references will be missed. This highlights the trade-off between precision and recall in a successful search. In contrast, a diligent search, carried out by a specialist, can successfully uncover the key art. 

A critical factor in yielding effective prior art and, ultimately, a successful outcome is the interaction between the client and the search team. Several factors, which are rooted in patent law, must be considered when putting forward a prior art invalidity defence. These include the parties’ interpretations of the asserted claims, the ability to combine prior art references and illustrate a defensible publication date, and potential estoppel issues. These factors carry through to the prior art search process.

In the case at hand there were four discussions between the attorney client and the search team, which highlights the importance of two-way knowledge sharing. Figure 1 demonstrates:

• the project background call;
• a review of interim findings and the strength of potential primary references;
• a narrowing of the search focus as the inter partes review takes shapes; and
• the final discussion to confirm the features addressed and the merits of potential combination references. 

The specific agenda for each discussion highlighted the hurdles to overcome and the shifting knowledge-transfer roles. The project background discussion was driven by the attorney team and provided a succinct overview of the known art and the gaps to address. In addition, it also covered any pre-existing claim construction implications, previously submitted art and potential estoppel issues. As a result, the search team was able to confirm the key factors shaping the focus of the search, focus the search effort and raise questions regarding claim interpretation.

As the effort progressed, the client fine-tuned the search focus to address specific features, while also exploring our rationale for flagging select references and confirming the key features disclosed. The interim discussions entailed a review of the findings, in which the client was able to confirm the limitations of the asserted claims that were effectively addressed by the found art. This included a mutual discussion between the search team and the client with regard to the strength of both the key references and the various combination arguments. 

As the search continued, the legal team built its arguments for the inter partes review and held regular discussions with the search team. The client shared the structure of its arguments with identified weaknesses that secondary references would be needed to overcome (see Figure 1, discussion three.) This feedback guided the search (ie, for a desired secondary reference and additional primary reference). The search team uncovered additional references, often convening to discuss the technical merits of the references and our recommendations on how to build a combination argument; this information was shared with the legal team and discussion four entailed a talk on the merits of the top findings, the potential combinations and the ability to meet the test for obviousness. 

In the end, the client prevailed in having all 19 challenged claims instituted on the merits, on all 103 grounds. 

Key takeaways

The litigation attorney handling an inter partes review plays a central role in the search for prior art. The search team, on the other hand, must be adept in communicating regularly with the client’s legal team to design and execute a diligent search and to assist in building a strong invalidity argument. The legal team and search team cannot carry out the search for prior art separately; the close interaction between the attorney and the search team plays an essential role in a successful outcome and reflects the need for knowledge transfer to overcome multiple hurdles.