Client Alert – Federal Circuit Update: Three Key Patent Decisions (April 2026)

These decisions reinforce three recurring themes in patent law:

1. Standing is essential for Federal Circuit review, even after full PTAB proceedings.
2. Inventorship errors are high‑risk, and not always curable.
3. Prosecution history lives forever and can decisively shape claim scope.

1. Standing Still Matters on Appeal. In  ironSource v. Digital Turbine (Fed. Cir. Apr. 7, 2026), the Federal Circuit dismissed ironSource’s appeal of a PTAB post‑grant review decision for lack of Article III standing.

What happened: ironSource challenged the PTAB’s decision allowing Digital Turbine to amend its patent claims. But when ironSource appealed, the court held it failed to show a concrete injury, such as a real risk of infringing the amended claims. ironSource relied on prior “veiled threats” of infringement tied to earlier, broader claims and a discontinued product. That was not enough. The court emphasized that to establish standing, a challenger must show concrete plans that would likely infringe the specific claims on appeal, including newly added narrowing limitations.

Why it matters: PTAB challengers do not need standing to file a petition, but they do need it to appeal. Allegations tied to old products or earlier claim versions do not suffice. Evidence must clearly link future business plans to the claims actually at issue. Before appealing a PTAB loss, challengers must carefully document how the current claims create a real and imminent business injury.

2. Failure to Name a Co‑Inventor Can Be Fatal. In Fortress Iron v. Digger Specialties (Fed. Cir. Apr. 2, 2026),in a precedential decision of first impression, the Federal Circuit held that patents with an omitted inventor are invalid if the error cannot be corrected under the Patent Act.

What happened: Fortress’s patents omitted a co‑inventor, whose contributions were undisputed. Fortress could not locate him and therefore could not provide notice and an opportunity to be heard—requirements for judicial correction under 35 U.S.C. § 256(b). The court held that an omitted inventor is a “party concerned” entitled to those procedural protections. Because correction was impossible, the patents were invalid.

Why it matters: Section 256 can save patents but only if its requirements are satisfied. A missing inventor cannot be bypassed. The court reaffirmed that all true inventors must be named, or the patent risks invalidity. Getting inventorship right from the start isn’t just best practice, it is critical to enforceability.

3. Prosecution Statements Can Dramatically Narrow Claims. In Puradigm v. DBG Group (Fed. Cir. Apr. 1, 2026) (Nonprecedential), the Federal Circuit affirmed summary judgment of non‑infringement based on prosecution history disclaimer.

What happened: During prosecution, the patent applicant distinguished prior art by asserting it did not disclose a “specular UV reflector.” Although the examiner disagreed, the court held that the applicant’s clear statements amounted to a disclaimer of reflectors made from polished aluminum—and, by extension, unpolished aluminum as well. Because the accused products used aluminum reflectors, they fell outside the narrowed claim scope.

Why it matters: Arguments can limit claims, even if the examiner does not rely on them. Courts focus on what the applicant said, not whether they later stayed silent. Disclaimers can extend logically to related variants of disclaimed subject matter. Words matter during prosecution. Strategic arguments today can foreclose enforcement options tomorrow.

For additional information, please contact: Alastair J. Warr at [email protected]