Filing a Post-Grant or Inter Partes Review

Before taking the step of filing a patent challenge, there’s a lot more to consider than just whether a claim seems invalid. Post-grant proceedings like Inter Partes Reviews (IPRs) and Post-Grant Reviews (PGRs) are powerful tools that can reshape the landscape of intellectual property disputes. They offer defendants a quicker, more technical route to contest a patent’s validity, but they also carry strategic, financial, and procedural traps that can have long-term consequences.

Understanding when and how to use these tools is key. As David Tobin of McDermott Will & Schulte LLP underscores, it is critical to understand your options before you act. Recent developments at the Patent Trial and Appeal Board (PTAB), including new USPTO Director guidance on discretionary denials designed to prevent duplicative proceedings and to ensure that PTAB cases are efficient alternatives to district court litigation, have made timing and case strategy more important than ever. The PTAB was designed to streamline the process of challenging questionable patents, but the rules have evolved significantly since its creation under the America Invents Act (AIA). Today, a successful filing demands not only legal insight but also careful coordination between business, legal, and technical teams.

When To File

Anyone other than the patent owner can file a PGR or IPR, however a party that has already filed a civil action challenging a patent’s validity cannot later file an IPR or PGR.

A PGR can be filed within nine months after the patent is issued, while an IPR can be filed any time after that period. That nine-month window is critical because it determines which types of arguments can be raised. In a PGR, a patent can be challenged on any statutory ground, including subject matter eligibility, written description, or enablement, while IPRs are limited to anticipation and obviousness arguments based on patents and printed publications.

Filing early may seem aggressive, but it can be a smart move, especially if a potentially problematic patent surfaces during freedom-to-operate analyses. Early action can help challengers to avoid the higher estoppel risks that follow an IPR decision. For business leaders, it’s worth considering these filings as part of broader risk management. The cost of waiting can be far higher than acting early.

Standing and Appeal Rights

Standing doesn’t matter much when filing a petition (assuming no statutory bars), but it matters later. “You don’t need standing to file, but you do to appeal. That’s a nuance that can catch people off guard,” cautions Patrick Richards of Much Shelist, P.C.

The Federal Circuit requires a concrete injury to appeal, meaning a petitioner who isn’t directly threatened by enforcement may be left without recourse. This creates strategic tension: some entities, such as industry groups or third-party funders, may initiate a challenge but ultimately have no standing to appeal if the PTAB rules against them. Balancing advocacy, ownership, and risk exposure is therefore critical.

Building a Strong Petition

A strong petition must tell a clear, particularized story of why a patent claim is invalid. The PTAB expects precision: each claim, prior art reference, and argument must be mapped explicitly and supported with evidence. The PTAB disfavors overly broad or scattershot petitions; specificity and clarity can make or break a petition. Petitioners should avoid relying too heavily on expert declarations without integrating those points into the main text of the petition.

The Standards of Review and Evidence

For IPRs, the ‘standard for institution’ is whether the petitioner has a ‘reasonable likelihood’ of success. For PGRs, the threshold is slightly higher: ‘more likely than not.’ After institution, both use the ‘preponderance of the evidence’ standard, which is less stringent than the ‘clear and convincing’ standard applied in district court litigation.

These differences make the PTAB an attractive venue for validity disputes. But petitioners must still present a focused and credible argument from the outset. Failing to properly construe claims or provide adequate evidence can lead to dismissal before reaching the merits.

Cost, Timing, and Strategic Considerations

An IPR typically costs around $50,000 in filing and post-institution fees, while a PGR is closer to $60,000. These costs rise quickly when challenging patents with more than 20 claims, and they don’t include legal fees or expert costs, which can easily double or triple total expenses.

“The PTAB is fast, but not cheap. It’s an investment in clarity,” notes Jeremy Albright of Norton Rose Fulbright US LLP.

The process from filing to final written decision generally takes about 18 months, though extensions may occur for complex cases. Coordinating among co-defendants can reduce costs but may also create complications around ‘real party in interest’ issues and estoppel.

Amending Claims and Other Avenues

Under recent USPTO rules, patent owners may now file motions to amend their claims during PTAB proceedings. But beware, amendments can cut off past damages and open the door to new prior art challenges. When an amendment is too risky, another option is an ex parte reexamination: an alternative post-grant process handled by a patent examiner rather than the PTAB. As Andrea Shoffstall of Unified Patents notes, “Ex parte reexams are another outlet for challenges. They can be slower, but they still work.”

Amendments and ex parte reexaminations offer different advantages depending on the end goal, whether that’s clearing a competitor’s patent or strengthening one’s own.

Key Takeaways

Post-grant challenges remain a cornerstone of modern patent strategy, but they’re not one-size-fits-all. Whether you’re defending your company’s intellectual property or challenging a competitor’s, success depends on understanding the interplay between timing, cost, and risk. The best-prepared parties approach the PTAB with the same precision they would a courtroom.

To navigate these proceedings effectively:

Track deadlines. The nine-month PGR and one-year IPR bars are hard limits, not suggestions. Missing them can close the door to powerful defensive tools.
Know denial triggers. Discretionary denials can derail even the strongest case if the district court timeline or patent age works against you.
Identify real parties early. Overlapping interests between funders, licensees, or co-defendants can raise estoppel and standing issues that can be difficult to unwind later.
Focus the arguments. The PTAB rewards clarity and precision, not volume. Every sentence in a petition should serve a purpose.

The PTAB is a forum where preparation, data, and narrative persuasion meet technical rigor. Ultimately, the value of these proceedings lies not just in invalidating weak patents, but in shaping a company’s long-term IP posture.

To learn more about this topic, view Things to Consider Before You File. The quoted remarks referenced in this article were made either during this webinar or shortly thereafter during post-webinar interviews with the panelists. Readers may also be interested in reading other articles about intellectual property.

This article was originally published here.