Sep 10, 2023Legal
PGR vs. IPR: Key Differences and Considerations for Patent Challenges


In the world of patent law, Post-Grant Review (PGR) and Inter Partes Review (IPR) are crucial mechanisms for challenging the validity of issued patents. Understanding the differences between PGR and IPR is essential for patent owners and challengers alike. This article explores the key distinctions and important considerations when navigating these two patent challenge processes.

1. The Nature of the Proceedings:

PGR: Post-Grant Review is a mechanism introduced by the America Invents Act (AIA) for challenging patents that were granted on or after March 16, 2013. PGR allows for broader challenges, including issues related to patentable subject matter, prior art, and enablement.

IPR: Inter Partes Review, also established by the AIA, is designed for challenging patents on narrower grounds. IPR mainly focuses on the novelty and obviousness of patent claims based on prior art.

2. Timing and Eligibility:

PGR: PGR petitions must be filed within nine months of a patent grant. This process is available for a broader range of patents, including those in technology areas like biotechnology and business methods.

IPR: IPR petitions can be filed any time after the nine-month window for PGR has passed or after a Post-Grant Review proceeding. IPR is primarily used for challenging patents related to mechanical or electrical technologies.

3. Scope of Estoppel:

PGR: One key consideration for challengers in PGR proceedings is the scope of estoppel. If a claim is challenged in a PGR and a final written decision is reached, the petitioner is estopped from pursuing any invalidity grounds that were or reasonably could have been raised in the PGR.

IPR: IPR estoppel is generally narrower. It applies only to grounds that were actually raised in the IPR proceedings or could have been reasonably raised. This provides more flexibility for subsequent challenges.

4. Discovery and Oral Hearing:

PGR: PGR proceedings allow for more extensive discovery, which can involve depositions and the production of documents. Additionally, PGR cases are more likely to proceed to an oral hearing.

IPR: IPR proceedings have limited discovery, making them more cost-effective and faster. Oral hearings are less common in IPR. 


Both PGR and IPR proceedings play a significant role in challenging patents, and choosing the right approach depends on various factors, including the nature of the patent, timing, and the desired scope of challenge. Patent challengers and owners must carefully evaluate these key differences and considerations when planning their strategies for patent challenges. By understanding the nuances of PGR and IPR, stakeholders can make informed decisions that align with their goals in the complex landscape of patent law.

We are excited to announce a significant expansion of our annual IPR Intelligence Report. Starting this year, we have transformed it into the PTAB Intelligence Report, covering a broader spectrum of proceedings within the Patent Trial and Appeal Board (PTAB). This evolution includes the addition of Post-Grant Review (PGR), Covered Business Method (CBM), and Derivative (DER) proceedings to our comprehensive analysis. By incorporating these new elements, the PTAB Intelligence Report provides an even more extensive and valuable resource for the intellectual property community. This transformation is part of our ongoing commitment to delivering insightful analysis and staying at the forefront of patent law trends.

Be the first to comment.