Insights

In Fortress Iron, LP v. Digger Specialties, Inc., No. 24-2313 (Fed. Cir. Apr. 2, 2026), the U.S. Court of Appeals for the Federal Circuit reaffirmed what happens when a patent incorrectly lists the true inventors, and that error cannot be corrected under 35 U.S.C. § 256(b), which requires notice and a hearing for all “parties concerned.” In Fortress, the patent owner sought judicial correction to add an inventor under § 256(b), but that inventor could not be located. Because the missing inventor qualified as a “concerned” party under the statute, the lack of notice and a hearing for that inventor made correction under § 256(b) impossible, and the patents could not be saved from invalidity.

Pharmaceutical innovators typically seek broad patent protection for their discoveries in order to prevent others from exploiting not only the specific embodiments the innovator wishes to pursue commercially, but also functional equivalents. But what happens when the additional functional equivalents that the innovator seeks to protect are not expressly disclosed in the patent? The Supreme Court recently addressed this issue in Amgen v. Sanofi.