The scope of the claim depends on the meaning of each word in the claim. The indefiniteness standard requires that a patent specification “conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.” In Nautilus, Inc. v. Biosig Instruments, Inc., the Supreme Court announced a new indefiniteness standard. The Court abrogated the Federal Circuit’s previous inquiry into whether patent claims were “amenable to construction” or “insolubly ambiguous.” Under the new standard, a patent is invalid for indefiniteness if its claims, read in light of the specification delineating the patent, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention. While the Supreme Court provides guidance for indefiniteness, the Federal Circuit is providing some helpful guidelines.
- Teva Pharms. USA, Inc. v. Sandoz, Inc.
After the holding in Nautilus, the Federal Circuit in Teva Pharms. USA, Inc. v. Sandoz, Inc., applied the new indefiniteness standard. The claim limitation at issue recited the term “molecular weight.” Three relevant measures existed for molecular weight such as: (1) peak average molecular weight (“Mp”); (2) number average molecular weight (“Mn”); and (3) weight average molecular weight (“Mw”).
The Federal Circuit found the indefiniteness of the claim because the claims, specification, and prosecution history did not convey to one of skill in the art with reasonable certainty. Neither the claims nor the specification contained an explicit definition of molecular weight, and the prosecution history contained inconsistent statements. The Federal Circuit invalidated the patent for indefiniteness.
- Dow Chem. Co. v. Nova Chems. Corp. (Can.)
In Dow Chem. Co. v. Nova Chems. Corp. (Can.), the Federal Circuit applied the Teva’s indefiniteness standard again. The claim term at issue here provides for “a slope of strain hardening . . . .” Nova argued that the term is indefinite because the patent fails to teach with reasonable certainty where and how the “slope of strain hardening” should be measured.
Dow’s expert testified that “one of ordinary skill in the art would know that the slope of the hardening curve would have to be measured at its maximum value . . . .” However, four methods were known to measure the maximum slope. Neither the patent claims nor the specification discussed the four methods. Moreover, the prosecution history did not provide any guidance.
The Federal Circuit held that the term in the claim is indefinite. The Federal Circuit emphasized that even Dow’s expert, a person of ordinary skill in the art, had developed a method for measuring maximum slope, and the required guidance was not provided by the claims, specification, and prosecution history. The Federal Circuit invalidated Dow’s patent because of the indefiniteness of the claim.
- Akzo Nobel Coatings, Inc. v. Dow Chem. Co.
Unlike Teva Pharms. USA, Inc. and Dow Chem. Co., in Akzo Nobel Coatings, Inc. v. Dow Chem. Co., the Federal Circuit found that the claims were definite. Dow argued that: (1) “viscosity below 10 Pa*s” was indefinite because it failed to recite the temperature at which the viscosity measurement was to be taken; and (2) “carried out at a temperature between 5°C [41°F] to 150°C [302°F] above the melting point of the polymer” was indefinite because it failed to specify which steps in the claimed process occurred at those elevated temperatures.
First, the Federal Circuit determined that one of ordinary skill in the art would measure viscosity based on extrinsic evidence and intrinsic record. There were two pieces of extrinsic evidence: Dr. Mount’s declaration, and the American Society for Testing and Materials (“ASTM”) protocol. Dr. Mount’s declaration recited that “if a temperature is not specified for a given measurement, room temperature is implied.” But the ASTM protocol did indicate that viscosity varies with temperature. The ASTM protocol disclosed that “[a] test method [for] the determination of the apparent viscosity of hot melt adhesives . . . at temperatures up to 175°C [347°F], . . . [and] report[ing] the apparent viscosity at a given temperature along with the particulars . . . .”
The Federal Circuit held that one of ordinary skill in the art would understand that room temperature is implied for a viscosity measurement with no specified temperature. The Court also noted that the District Court did not clearly err in crediting Dr. Mount’s declaration over the ASTM protocol because the described method in the ASTM protocol only discussed “hot melt adhesives” above 175°C (347°F) aims to find different viscosities over a range of temperatures.
Moreover, the Federal Circuit found that the intrinsic record further supported the definiteness of the claim because room temperature is the only temperature mentioned at all in the patent in connection with a viscosity measurement.
Second, the Federal Circuit held that “carried out at a temperature between 5 °C [41°F] to 150 °C [302°F] above the melting point of the polymer” limitation is definiteness based on the specification of the patent. Furthermore, the Federal Circuit emphasized Dow’s burden of proof and noted that Dow did not provide any evidence to show that a person of ordinary skill in the art would not know the limitation with reasonable certainty, contrary to the clear meaning of the intrinsic record.
In sum, the Federal Circuit found the claims definite, relying on extrinsic evidence and the intrinsic record. The Court also clarified that the party who alleges indefiniteness of the claim has the burden of proof.
- Eli Lilly & Co. v. Teva Parenteral Meds., Inc.
In Eli Lilly & Co. v. Teva Parenteral Meds., Inc., relying on expert testimony and the doctrine of claim differentiation, the Federal Circuit held that the claim is definite. The issue was indefiniteness of the term “vitamin B12.” Depending on the context, “vitamin B12” can be used in the art to refer either to cyanocobalamin specifically or, more broadly, to a class of compounds including pharmaceutical derivatives of cyanocobalamin.
Eli Lilly’s expert testified that, although “vitamin B12” can refer to a class of compounds in other contexts, it refers specifically to cyanocobalamin when “vitamin B12” is prescribed in the medical field.
The District Court relied on the expert’s testimony and concluded that the term “vitamin B12” was definite. The Federal Circuit held that there is no clear error in the District Court’s conclusion that “vitamin B12,” when used to refer to vitamin B12 supplementation in a medical context, refers to “cyanocobalamin.”
The Federal Circuit also considered the doctrine of claim differentiation. Claim 1 listed both “vitamin B12” and cyanocobalamin as suitable agents for use in the claimed method. Claim 2 limited the agent to “vitamin B12” alone. If “vitamin B12” were to refer to a class of compounds, then claim 2 would be the same scope as claim 1.
However, the doctrine of claim differentiation presumes that dependent claims are “of narrower scope than the independent claims from which they depend.” The Federal Circuit noted that reading the claims to require “vitamin B12” to be a specific compound would avoid rendering claim 2 narrower in scope than claim 1.
In sum, the Federal Circuit found that a person of ordinary skill in the art would understand that “vitamin B12” in the claim referred specifically to cyanocobalamin in the realm of medical treatment, thereby providing “reasonable certainty” as required under Nautilus.
To determine indefiniteness, the Federal Circuit considers extrinsic evidence, including expert testimony, and intrinsic record, such as claims, the structure of claims, and the specifications. These Federal Circuit decisions provide useful guidance for the Supreme Court’s new indefiniteness standard.
 35 U.S.C. § 112.
 See 134 S. Ct. 2120, 2124 (2014).
 Id. at 2122.
 See id.
 See 789 F.3d 1335, 1338 (Fed. Cir. 2015).
 Id. at 1341.
 Id. at 1341–44.
 Id. at 1338.
 See 803 F.3d 620, 621 (Fed. Cir. 2015).
 Id. at 631.
 Id. at 633.
 See Dow Chem. Co. v. Nova Chems. Corp. (Can.), 458 F. App’x 910, 919 (Fed. Cir. 2012).
 Dow Chem. Co., 803 F.3d at 631.
 Id. at 634.
 Id. at 635.
 Id. at 634.
 Id. at 621.
 811 F.3d 1334, 1345 (Fed. Cir. 2016).
 Id. at 1343.
 Id. at 1343–44.
 Id. at 1344.
 Id. at 1344–45.
 Id. at 1345.
 845 F.3d 1357, 1370 (Fed. Cir. 2017).
 See Eli Lilly & Co. v. Teva Parenteral Meds., Inc., No. 1:10-cv-1376-TWP-DKL, 2012 U.S. Dist. LEXIS 85369, at *26–28 (S.D. Ind. June 20, 2012).
 845 F.3d 1357 at 1371.
 See AK Steel Corp. v. Sollac & Ugine, 344 F.3d 1234, 1242 (Fed. Cir. 2003).
 Eli Lilly & Co., 845 F.3d at 1371.
 Id. at 1370.