In Forum U.S. Inc., v. Flow Valve, LLC, No. 2018-1765 (Fed. Cir. Jun. 17, 2019), the Federal Circuit affirmed the U.S. District Court for the Western District of Oklahoma, holding Flow Valve’s reissue patent No. RE45,878 was invalid under 35 U.S.C. § 251(a) because “[t]he original patent [did] not disclose the invention claimed in the reissue patent.”

Here, Flow Valve’s original patent disclosed and claimed embodiments comprising a “plurality of arbors.” In the reissue patent, Flow Valve broadened the claims to include embodiments that do not explicitly require the use of “arbors.” The district court found this fact dispositive, pointing out that neither the written description nor the drawings disclose that arbors are an optional feature of the invention. Flow Valve argued that a person of ordinary skill in the art would have understood from the specification as a whole that the arbors were an optional feature, supporting this position with a declaration from an expert witness.

The district court found this argument unpersuasive, and the Federal Circuit agreed, determining that the understanding of a person of ordinary skill in the art, alone, did “not aid the Court in understanding what the” original patent disclosed. The Court relied on its current precedent that the specification of the original patent must do more than merely suggest or indicate the invention recited in reissue claims. Rather, in the Court’s view, Section 251(a) requires the original patent to “clearly and unequivocally disclose” the newly claimed invention. Accordingly, the Court upheld the district court’s determination.