Rebuttal Strategy to Tackle Patent Invalidation Suit Targeting ‘Ambiguous’ Claims

A patent can be defined as an exclusive right granted for an invention. Oftentimes, these patents are challenged on the grounds of insufficient or ambiguous specification and claims, codified under 35 US Code (USC) 112. In such a scenario, there are chances that the patent might get invalidated, resulting in a loss for the patent owner. In order to prevent this from happening, businesses need to have an effective rebuttal strategy in place. The following article discusses patent invalidation and the rebuttal strategy to defend a patent challenged on similar grounds.

Patent Invalidation

A patent is invalidated when an infringer countersues the patent holder with solid evidence that can be – one or more prior arts for the patent, improper claim enablement, insufficient disclosure of the claimed subject matter in the specification, and the likes of it. To that end, various laws are cited. Examples of those laws may include 35 USC 101, 35 USC 102, 35 USC 103, and 35 USC 112. Such laws include different variations under which the patent is invalidated.

For instance, a patent can be invalidated under variations of 35 USC 112 (first paragraph, second paragraph, third paragraph, fourth paragraph, fifth paragraph, or sixth paragraph) due to insufficient or ambiguous specifications and claims of the patent.

Rebuttal Strategy for Patent Invalidation Under 35 USC 112

Once a patent invalidity allegation is made by the infringer with support of the respective patent office (such as the United States Patent and Trademark Office), the patent holder needs to counter the allegation with evidence. Such evidence would be the filed specification and claims. The patent holder or a representative of the patent holder, such as a patent analyst of an intellectual property rights consultancy firm, can draft rebuttals in response to the allegations.

To that end, the specification is analyzed in view of the allegations. However, it is not an easy task to analyze the specification and provide rebuttals as the analyst needs to understand the field of the invention. Also, the analyst is required to have sufficient knowledge of patent laws. The figure below mentions some common pitfalls to avoid while drafting rebuttals for USC 112-based rejections:

Figure: 5 pitfalls to avoid while drafting rebuttals for USC 112-based rejections

Drafting Rebuttal Strategy – An Example

Problem Statement: For instance, let’s assume that a claim is reciting an amplifier. Since there is no explicit mention of the term “amplifier” in the specification, the patent is invalidated under USC 112, first paragraph rejection due to non-disclosure of the term “amplifier”. In such a case, the analyst might not be able to draft rebuttals if he/she makes the above-mentioned mistakes.

Solution: To draft the rebuttals, the analyst would have to give the broadest possible meaning to the subject matter disclosed in the specification. For instance, the specification discloses a transistor which increases the strength of a weak signal. This is a known fact that the transistor can work as an amplifier. The analyst can provide support of the disclosed transistor and its operation for the usage of the term “amplifier” in the claims.

To that end, the analyst needs to know the basics of the field of invention of the subject patent. Accordingly, the analyst can provide strong rebuttals for the allegations under 35 USC 112 rejections.

Once the specification is analyzed and the strategy for the rebuttals is formulated, the analyst can provide support for the claimed subject matter from the specification and comments to strengthen the rebuttals.


Patent invalidation is a common business strategy adopted by organizations in order to countersue a patent holder. Therefore, it becomes necessary to have properly drafted claims and specifications in place to prevent them from derailing one’s case. Strong claims and specifications strengthen rebuttal strategy and stop competitors from circumventing them for their benefit.

Sagacious IP’s patent drafting and prosecution service aims to provide end-to-end support to businesses in drafting effective patent claims and handling litigations pertaining to patent invalidation. Our patent practitioners are trained subject matter experts committed to providing the most cost-effective patent drafting solutions.

-Neha Malia (ICT Drafting and Prosecution) and the Editorial Team

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