What is Patent Reexamination?
Patent Reexamination is a legal process that allows a patent’s validity to be reviewed by the patent office after it has been granted. This process is typically requested when new prior art is discovered that may affect the original patent claims.
Reexamination can be initiated by third parties, such as competitors, or by the patent owner to strengthen a patent’s enforceability. The process is conducted by the United States Patent and Trademark Office (USPTO) or other national patent offices.
Why Patent Reexamination matters for Businesses and Patent Holders?
Patent Reexamination serves multiple strategic purposes, including:
- Defending against invalidation – Patent owners can request reexamination to reinforce their patent’s claims.
- Challenging a competitor’s patent – Businesses may request reexamination to weaken a competitor’s patent that poses a legal or commercial threat.
- Reducing litigation risks – Reexamination can be used as an alternative to costly Patent Litigation.
- Ensuring patent strength – Patents that survive reexamination become more valuable and enforceable.
Types of Patent Reexamination
1. Ex Parte Reexamination
- Requested by the patent owner or a third party but does not involve the requester after submission.
- The patent examiner reviews the new evidence and decides whether to uphold, modify, or cancel the patent claims.
- The patent holder can respond, but third-party requesters do not participate further.
2. Inter Partes Reexamination (Now Replaced by Inter Partes Review – IPR)
- Previously allowed third parties to actively participate in the reexamination process.
- Replaced in the U.S. by Inter Partes Review (IPR) under the America Invents Act (AIA) in 2012.
3. Supplemental Examination
- A patent owner requests a review of their own patent to correct or clarify claims before litigation.
- Can prevent claims of inequitable conduct, which might otherwise render a patent unenforceable.
Example: A pharmaceutical company discovers previously overlooked research papers that question the novelty of a competitor’s drug patent. The company files for Ex Parte Reexamination, leading to partial invalidation of the competitor’s patent, opening the market for competition.
Challenges in Patent Reexamination
Patent Reexamination can be beneficial but presents challenges, such as:
- Uncertain outcomes – Claims may be upheld, modified, or canceled, impacting patent value.
- Lengthy process – Ex Parte Reexaminations can take months or years to complete.
- Litigation risks – If a patent is weakened or invalidated, it may become more vulnerable to legal challenges.
- Competitive strategy impact – Filing for reexamination against a competitor’s patent may lead to counteractions.
Strategic Business use of Patent Reexamination
Companies use Patent Reexamination to:
- Strengthen their own patents before licensing or enforcement.
- Challenge weak patents held by competitors to gain market advantage.
- Avoid costly litigation by resolving patent disputes through administrative review.
- Improve patent portfolio value by ensuring stronger, more enforceable claims.
Frequently Asked Questions on Patent Reexamination
1. Who can request a patent reexamination?
Any party, including competitors, the patent owner, or the USPTO itself, can request ex parte reexamination. However, inter partes reexamination (now replaced by inter partes review) allowed third parties to challenge a patent more actively before it was phased out in 2012.
2. What happens if a patent fails reexamination?
If the USPTO finds the patent invalid based on new prior art, the patent may be canceled, narrowed, or amended. If the claims are upheld, the patent remains enforceable. Reexamination can significantly impact ongoing infringement lawsuits.
3. How does reexamination differ from post-grant review (PGR)?
Reexamination focuses only on prior art challenges (patents and printed publications), while PGR allows broader challenges, including lack of novelty, obviousness, and indefiniteness. PGR must be filed within nine months of patent issuance, whereas reexamination can be requested at any time.