The Most Successful Grounds for Patent Appeals at the Federal Circuit

Intro: Appealing a decision from the Patent Trial and Appeal Board (PTAB) or a district court to the U.S. Court of Appeals for the Federal Circuit is always an uphill battle. Statistics show that most patent appeals result in the Federal Circuit affirming the lower tribunal’s decision. However, certain legal arguments succeed more frequently than others. In this article, we examine the most successful grounds for appeal in patent cases, focusing on trends in claim construction, obviousness, and procedural errors.

1. Claim Construction Errors

Why It Succeeds: Claim construction is a question of law reviewed de novo (without deference to the PTAB or district court). This gives appellants the best chance to overturn an adverse decision.

• Example: Teva Pharm. USA, Inc. v. Sandoz, Inc., 574 U.S. 318 (2015), clarified that while factual findings are reviewed for clear error, legal interpretation of claim terms remains de novo.

• Recent Cases:

  • HD Silicon Solutions v. Microchip Technology (2025): The Federal Circuit disagreed with the PTAB’s claim construction but upheld the ruling on alternate obviousness grounds.

  • Apple Inc. v. Vidal (2023): Claim construction errors led to vacatur of certain PTAB findings.

Tip: Appealing based on misinterpretation of claim terms (especially technical terms of art) remains one of the highest-probability grounds for reversal.

2. Procedural or Due Process Violations

Why It Succeeds: The Federal Circuit carefully scrutinizes whether parties were denied a fair opportunity to present arguments or evidence.

• Example: If the PTAB introduces a new theory or relies on evidence not raised by the parties, the decision can be vacated.

• Case: In re Magnum Oil Tools Int’l, Ltd., 829 F.3d 1364 (Fed. Cir. 2016), reversed a PTAB decision because the Board improperly made the petitioner’s arguments for them.

Tip: Highlight lack of notice, new grounds of rejection, or failure to consider key evidence to increase the odds of vacatur or remand.

3. Insufficient Articulated Reasoning for Obviousness

Why It Succeeds: The Federal Circuit requires that PTAB decisions on obviousness be based on specific, reasoned analysis, not conclusory statements.

• Case: In re Kahn, 441 F.3d 977 (Fed. Cir. 2006) – “Rejections on obviousness grounds cannot be sustained by mere conclusory statements; there must be articulated reasoning with rational underpinning.”

• More Cases:

  • Weber, Inc. v. Provisur Technologies (2024): PTAB’s obviousness finding vacated for lack of a clear motivation to combine.

  • Metalcraft of Mayville v. Toro Co., 848 F.3d 1358 (Fed. Cir. 2017): Overturned due to hindsight-driven combination rationale.

Tip: If the PTAB’s obviousness rationale is weak, unsupported by evidence, or heavily reliant on hindsight, it’s a strong appellate issue.

4. Misapplication of § 101 (Patent Eligibility)

Why It Succeeds: Although § 101 issues are often challenging, Federal Circuit reversals are not uncommon where the tribunal oversimplified claims as “abstract ideas.”

• Case: Enfish, LLC v. Microsoft Corp., 822 F.3d 1327 (Fed. Cir. 2016) – Reversal due to improper characterization of software claims as abstract.

• Recent Trends: The Federal Circuit has become more nuanced in analyzing step one of the Alice/Mayo test, especially for AI and software patents.

Tip: Appeals focusing on the technical improvement over prior art have better success rates under § 101 challenges.

5. Errors in Secondary Considerations of Non-Obviousness

Why It Succeeds: The PTAB sometimes fails to fully consider objective indicia such as commercial success, long-felt need, or industry praise.

• Case: Leo Pharmaceutical Products v. Rea, 726 F.3d 1346 (Fed. Cir. 2013) – PTAB reversed for failing to weigh strong secondary considerations.

• Trend: Federal Circuit decisions increasingly emphasize that objective evidence must be considered before concluding obviousness.

  
  

6. Statutory or Jurisdictional Errors

Why It Succeeds: Appeals raising statutory bars (e.g., § 315(b) timing, real-party-in-interest errors) succeed when the PTAB fails to apply rules correctly.

• Example: Arthrex, Inc. v. Smith & Nephew, Inc. (2021) – Structural constitutional issues resulted in vacatur of PTAB decisions.

• Trend: Settled expectations under § 314(a) and § 325(d) may become fertile grounds for future appeals. While you can’t directly appeal the discretion to deny, you may consider challenging how that discretion was exercised:

  • Was the decision arbitrary or capricious?

  • Did the PTAB fail to consider relevant evidence? The Board has noted there may be persuasive reasons why the Board should review challenged claims several years after their issuance date. For example, a significant change in law may have occurred since the patent issued, and a petitioner can explain how that change in law directly bears on the patentability of the challenged claims. As another example, a patent may have been in force for years but may not have been commercialized, asserted, marked, licensed, or otherwise applied in a petitioner’s particular technology space, if at all. If evidence was submitted, but not considered, a case may be made.

  • Did the denial conflict with statutory provisions, such as favoring the strong presumption of patent validity?

  • This is a long shot and settled expectations are very new. This highlights the needs for petitioners to submit evidence why challenged claims are being submitted years after issuance. This is particularly important for patents that have issued six (6) year or more before seeking Inter Partes Review.

Federal Circuit Statistics (2023–2025 Trends)

• Affirmance Rate: ~70–75% of PTAB appeals are affirmed.

• Partial Vacatur/Remand: ~10–15%.

• Reversal Rate: ~10–15%, with claim construction and procedural errors leading the reversals.

Conclusion

While most PTAB and district court decisions are upheld, claim construction errors, lack of articulated reasoning for obviousness, and procedural violations remain the most successful grounds for appeal. A sharp focus on these issues can preserve stronger arguments for the Federal Circuit.

Considering an appeal of a PTAB decision?

Contact Your Patent Counsel to evaluate your options. Drop us an email at jmeredith@yourpatentcounsel.com and include your patent and/or IPR Filing Number (e.g. IPR2025-00XXX) and we will pull the record and plan a time to discuss.

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