Validity Searches Part 1: Statistics reveal the best patent opposition strategies

To begin, we should explain why a corporation might want to check or question the validity of a patent. There are several different scenarios and reasons for a corporation to oppose a patent or question its validity:

  • The corporation may want to acquire the patent, and hence would want to check the validity of the patent before acquiring it.
  • The corporation may have been sued in a patent infringement suit, and hence wants to prove the patent invalid to save itself from paying exorbitant licensing fees.
  • The corporation may want to oppose the patent at a patent office to ensure that its competitor does not get a patent issued which could become a threat to the corporation in the future.

There could be other reasons as well, but primarily the three mentioned above are usually the reasons to check the validity of a patent.

Order through Searchstream and get the best prior art documents

Searchstream provides highly transparent, tightly scoped, legally compliant and timely search proposals.

What are the different approaches that corporations or their attorneys usually use to prove a patent invalid?

Evalueserve analyzed approximately 100 ‘successful’ patent oppositions at the EPO and 100 inter partes reviews at the USPTO across different industries – high-tech, chemistry, biotech, pharma, mechanical, etc.; and found that the attorneys usually use the following four approaches to oppose a patent:

  1. Identify a new prior art that the examiner did not find, and try to prove the new art USC 102 in the U.S. or novelty step ‘X’ in EP
    • This remains the strongest argument to oppose a patent both in the U.S. and EP, however finding such a document is always a challenge.
  2. Identify new prior art and try to make obviousness (USC 103 in U.S.) or inventive step argument (Y in EP)
    • This remains the most popular approach, and more than 50% of successful oppositions have used this approach.
  3. Use cited prior art documents, e.g., the examiner found prior art, or the art provided by the applicant of the patent itself, to make USC 102/X or USC 103/Y arguments, without relying on any new prior art document.
  4. Use legal arguments (without relying on any prior art document) to revoke the claims of the patent
    • This is only possible during oppositions in EP and in post grant reviews in the U.S. In inter partes review in the U.S., review only can be made based on USC 102 or 103 arguments.

Another interesting point that came out of the analysis was that in 40% of the successful oppositions/reviews using prior art documents, only patent documents were used as prior art.  In 13% of cases, only technical literature (also called non-patent literature, especially in the EPO) was used.

Validity Searches - Types of prior art documents

Let’s dig deeper into the data separately from U.S. and EP:


Trends from inter partes review in the U.S.

  • 88% of the reviews involve identifying a new prior art that was not cited and using it to successfully invalidate the patent.
  • In the remaining 12%, cited prior art documents were used to successfully review the patent without relying on any new prior art.
    • In such cases, the USC 102 argument was made successfully in 60% of the cases.

Validity Searches - 100 patent reviews

  • In the U.S., more than 50% successful reviews involve the use of both patent and technical literature prior art.

Trends from EP oppositions

Validity Searches Trends from EP opposition

  • In EP oppositions, 66% of the oppositions involve identifying a new prior art that was not cited, and using it to successfully oppose a patent
  • In just 5% of the cases, the examiner’s own prior art or applicant disclosed art is used to oppose the patent, without relying on any new prior art
  • In the remaining 30% of the cases, only legal arguments were used to invalidate the whole patent or a subset of the claims of the patent. Such arguments usually related to the following articles: Article 123(2); Article 100(c); Article 100(b); Article 101 3b; Article 83; Article 76 (1); Article 54 (3).

Validity Searches - 100 EP oppositions

  • The percentage of successful oppositions using technical literature alone (also called non-patent literature in the EPO) is higher in EP than in the US.

So, what have we learned from this analysis?

There are a few important lessons that we can gather from the analysis of both the U.S. and EP patent oppositions:

  • If a prior art document is identified by the examiner himself or even submitted by the applicant, it does not necessarily mean that the examiner will always thoroughly read it. Alternatively, there could also be a difference of opinion between the examining and the opposition parties with respect to interpretation of certain claim elements. Therefore, one can still use such a document and get a patent opposed – however, such cases are quite low in number.
  • It is even possible to argue on the legal aspects of the issued claims to get a patent opposed. For example, enablement of the claimed content or the scope of the subject matter claimed vs. disclosed in the specification, sufficiency of disclosure, amendments extending beyond the content of the application as filed, etc..
  • The most successful and the most sought-after option to oppose a patent, is to find new prior art documents that were not cited. (It’s logical that this is the most popular option, given its 66% success rate in EP!)
    • Due importance should be given to identify both patent and technical literature prior art documents. Case in point: in 60% of successful oppositions across the U.S. and EP, technical literature was used to oppose a patent, either as a standalone document or combined with patent prior art documents.

Therefore, it comes as no surprise that whenever a corporation wants to oppose or invalidate a patent, they use expert search firms to support them in identifying the best prior art documents.

Have you tried any of these approaches in the past? Let us know what you’ve found in the process of invalidating or opposing patents or if you have questions or comments!

In the second part of the blog series, we will discuss different approaches that can be used to find good prior art documents that the attorneys can use in their arguments to oppose or invalidate a patent.

Shekhar Khanduja
Associate Vice President, IP and R&D Solutions Posts

Shekhar Khanduja is an associate vice president at Evalueserve, leading a team of highly-energetic IP and R&D searchers and drafting/prosecution experts. He aims to instil a passion for innovation in his team to continually improve IP and R&D solutions though small organic innovations and knowledge management. Raising quality and ideas to improve IP and R&D searches is a favorite goal – closely followed by experimenting in the kitchen to improve family recipes! Shekhar is hoping readers of this blog will join the conversation and share their ideas that he and his team can test internally to improve knowledge processes.

Christy George
Christy George
Manager, IP and R&D Solutions Posts

Christy George is a manager for IP and R&D Solutions at Evalueserve. In this role, he works as part of a Research and Development team to enhance processes that directly impact the quality and execution of various IP projects. Formerly on the operations team, he has close to 10 years of experience leading teams of patent professionals for multiple clients in the high-tech domain. Christy is an expert in Search and Intelligence and is passionate about finding creative solutions to difficult problems. In his free time Christy is an avid numismatic, enjoying the hunt to find rare currencies.

Latest Posts