Invalidity search is a comprehensive and thorough search of prior art to draw out “one critical” reference that might invalidate an existing patent.


The basic purpose of conducting invalidity searches is to find a prior-art that predates the effective priority date of the target patent and thereby invalidate it. For that, invalidity searches do a critical patentability assessment of “target patent” on grounds of novelty, non-obviousness or combination of both.
Invalidity search is commissioned when enforceability of a patent has to be confirmed or some specific requirement has to be met, such as:

• In times when contemplating assertion, licensing, buying or selling of a patent;
• Patent infringement threat is anticipated;
• Litigation has to be initiated; or
• A petition for review of a patent has to be filed in the concerned patent office


As such there are no restrictions and documents published anywhere in the world and in any language are relevant. Generally differentiating between Novelty Destroying and Non-Obviousness Destroying Prior Art is difficult. However, following analogy should help.

#Simple Analogy to Understand That How A Patent Can Be Invalidated Using Concepts of “Novelty” & “Non-Obviousness” or “Both”
In most cases, it is relatively easy to invalidate a patent using a prior art on novelty grounds. Contrastingly, on obviousness requirement, it is a little difficult because it requires combining elements of prior art in such a way that it becomes apparent to someone skilled in the art.

To understand this, let’s assume “the patent in question” claims use of X i.e. a small molecule (a protease inhibitor) for treating cancer. Now for invalidating this patent, we need to find invalidating prior-art using following three strategies:

1. Novelty destroying prior-art

It could be a patent that claims exactly the same as “the patent in question”. It also claims use of X i.e. a small molecule (a protease inhibitor) for treating cancer. The only difference being that it was filed earlier than effective priority date of the target patent.

2. Non-obviousness destroying prior-art

A patent that claims use of protease inhibitor for treatment of cancer and a document that claims that X is a protease inhibitor can be combined together to invalidate the target patent.

3. Alternatively, a searcher may also look for patents that claim use of different molecules viz. Y, Z, A, B for treatment of cancer and use it in combination with those other prior-art documents that reveal that these molecules are protease inhibitors.


It is invariably recommended that invalidity searches are conducted by skilled professional prior-art researchers who:
– Have the desired domain knowledge to minutely understand the technical aspects of the patented invention.
– Are apt in using patent search tools and databases and using combinations of both simple & complex search strategies to find prior art references in multiple languages and in multiple jurisdictions.

# No Search is 100%

No search can guarantee that a magic reference that can be used to invalidate a patent will always be found. However, searches done by professionals ensure that closest results are returned helping you make informed decisions.


An invalidity search is also variously known as-
 Patent Strength Assessment Search,
 Patent Nullity Search,
 A search that ensures no prior art for the patent in question exists and it is, thus enforceable, is referred to as “Validity Search”.
 A search that is aimed to gather evidence to oppose a patent application that is close to getting a grant or a granted patent is referred to as “Opposition Search”.


Validity and Opposition Searches essentially uses the same search process as invalidity searches but differs in terms of client’s requirement/perspective.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s