Key Factors to Consider When Choosing Between Litigation and IPR

Your Patent Counsel
Jul 29
4 min read

Updated: Aug 2

1. Strength of Prior Art

An Inter Partes Review (IPR) is best suited for prior art-based challenges — specifically, patents or printed publications that anticipate or render the claims obvious. If your best arguments involve lack of written description, enablement, indefiniteness, or § 101 subject matter eligibility, these must be raised in district court — not at the PTAB.

✔ Choose IPR: When you have strong prior art that clearly targets the claims.

✔ Choose litigation: When your invalidity arguments depend on non-prior art grounds or require complex expert testimony.

2. Cost and Efficiency

IPRs are often more cost-effective than district court litigation. A full trial in district court can run into the millions. In contrast, IPR costs typically fall in the $300,000–$750,000 range, depending on complexity (type of technology, number of patent claims involved, number of prior art references and number of related patents).

✔ Choose IPR: To streamline the dispute, reduce discovery burdens, and focus on technical invalidity issues.

✔ Choose litigation: When broader strategic or business goals justify a full challenge, including damages or injunctive relief.

3. Number of Patents Involved

IPRs are filed one patent at a time, and each petition requires a substantial investment of time and money. If your case involves multiple asserted patents, the cumulative cost of filing separate IPRs for each one may outweigh the benefit — especially if your resources are limited or the patents are weak. The current USPTO fee to file an inter partes review (IPR) petition with the Patent Trial and Appeal Board (PTAB) is $23,750.00 for up to 20 claims. For each claim over 20, there is an additional fee of $470.00. If the PTAB institutes the review, a post-institution fee of $28,125.00 for up to 20 claims is due, with an additional fee of $940.00 for each claim exceeding 20. That is the USPTO filing fees alone (does not include attorney fees) and with multiple patents, it can get very expensive quickly.

✔ Choose litigation: If you're facing a large number of patents, and challenging them through IPR would be cost-prohibitive.

✔ Choose IPR selectively: When only one or two patents are particularly threatening or critical to the case.

4. Speed and Timing

The PTAB is required to issue a final written decision within 12 months of institution (extendable by 6 months in exceptional cases). District court cases, especially in busy jurisdictions, can take 2–5 years to reach final judgment.

✔ Choose IPR: For faster resolution of validity issues.

✔ Choose litigation: When time is not of the essence or if you need a decision on multiple legal fronts (e.g., infringement, damages, inequitable conduct).

5. Standard of Proof

The burden of proof is lower at the PTAB. Petitioners must show unpatentability by a preponderance of the evidence, compared to the clear and convincing evidence standard in district court.

✔ Choose IPR: If you have a close invalidity case that benefits from the lower threshold.

✔ Choose litigation: If your invalidity case is strong even under the higher standard.

6. Impact on Litigation

IPRs can be used strategically to stay district court proceedings. Many courts are receptive to granting a stay if the IPR is filed early and covers all asserted claims.

However, some courts may deny a stay — especially if litigation is far along or if the IPR only covers a subset of issues.

✔ Choose IPR: If you want to stay litigation or gain leverage in settlement.

✔ Choose litigation: When the PTAB might deny institution or if timing no longer favors a stay.

7. Estoppel Risk

If you file an IPR and go to final written decision, you are estopped from raising in litigation any grounds you raised or reasonably could have raised in the IPR.

✔ Choose IPR: When you are confident your petition includes your best prior art and arguments.

✔ Choose litigation: If you want flexibility to raise multiple invalidity defenses later.

🧭 Decision Matrix: IPR vs. Litigation

Factor	Inter Partes Review (IPR)	District Court Litigation
Cost	Lower overall cost: $250K–$800K per patent	High: Often $2M–$5M+ per case
Speed	12–18 months from filing to final written decision	3–6 years depending on jurisdiction and complexity
Scope of Challenge	Limited to prior art (patents/publications) and §§102/103	Broader: includes §101, §112, inequitable conduct, etc.
Standard of Proof	Lower: Preponderance of the evidence	Higher: Clear and convincing evidence
Forum	PTAB (administrative judges, no jury)	Federal District Court (judge and possibly jury)
Discovery	Very limited (depositions of experts/declarants only)	Full discovery: interrogatories, depositions, documents, etc.
Number of Patents Involved	One petition per patent; costly for multi-patent cases	Can address multiple patents in one action
Ability to Stay Litigation	Often increases chances of litigation stay if filed early	No automatic stay — litigation continues unless stayed by court
Risk of Estoppel	High: Estopped from raising grounds “raised or reasonably could have raised” in IPR after final decision	No estoppel beyond actual court rulings
Control Over Timing	Structured and predictable PTAB deadlines	Can be unpredictable; scheduling influenced by motions/court
Ideal Use Case	You have strong prior art and want to challenge validity efficiently	You need to assert multiple defenses or pursue damages
Appeal Rights	Final PTAB decision appealable to CAFC	Final judgment appealable to CAFC
Leverage in Settlement	Filing IPR can create early pressure to settle	Leverage builds closer to trial or after claim construction

🧩 Which Option Is Right for You?

Your Situation	Recommended Path
Strong prior art, want fast and focused challenge	✅ IPR
Multiple patents asserted against you	✅ Litigation or selective IPRs
Need to challenge non-prior art issues (e.g., §101, §112)	✅ Litigation
Concerned about estoppel effect of IPR	✅ Litigation
Budget-conscious with a strong prior art case	✅ IPR
Seeking broad discovery and damages	✅ Litigation