The Federal Circuit has spent the past few years applying the Supreme Court's most recent precedent, Nautilus, Inc. v. Biosig Instruments, Inc., on the indefiniteness standards in the patent statute.  35 U.S.C. § 112(b).  The Federal Circuit's latest decision, in IBSA Institut Biochimique, S.A. v. Teva Pharmaceuticals USA, Inc., affirmed a District Court's finding that the asserted claims to a pharmaceutical formulation were indefinite.

The case arose in ANDA litigation over IBSA's Tirosint® product, which is a soft gel capsule formulation of the active ingredient levothyroxine sodium, as claimed in U.S. Patent No. 7,723,390.  Claim 1 is representative of the asserted claims:

1.  A pharmaceutical composition comprising thyroid hormones or their sodium salts in the form of either:
    a)  a soft elastic capsule consisting of a shell of gelatin material containing a liquid or half-liquid inner phase comprising said thyroid hormones or their salts in a range between 0.001 and 1% by weight of said inner phase, dissolved in gelatin and/or glycerol, and optionally ethanol, said liquid or half-liquid inner phase being in direct contact with said shell without any interposed layers, or
    b)  a swallowable uniform soft-gel matrix comprising glycerol and said thyroid hormones or their salts in a range between 0.001 and 1% by weight of said matrix.

(where the italicized claim limitation was at issue regarding indefiniteness).  Important to the District Court's determination appears to be that the priority document for the '390 patent was an Italian patent written, appropriately, in Italian that was translated into English upon filing in the U.S.

IBSA urged below that "half-liquid" should be construed to mean "semi-liquid" to be interpreted as "having a thick consistency between solid and liquid."  Teva for its part argued that the term is indefinite, or in the alternative to mean "a non-solid, non-paste, non-gel, non-slurry, non-gas substance."  It was undisputed that the intrinsic evidence did not expressly define the term "half-liquid."  IBSA argued that the Italian priority document used the term "semiliquido" which was translated into "half-liquid" and that the skilled worker would understand from this translation that the terms were synonymous.  The District Court disagreed, noting "a number of differences between the certified translation and the '390 patent's specification" for terms other than "half-liquid."  Under these circumstances, the District Court held that the U.S. application that matured into the '390 patent was the document that "best reflected the applicant's intent" (which is somewhat paradoxical because it is unlikely that the applicant would intentionally rely on an ambiguous document).  Nevertheless, the District Court gave no weight to evidence regarding the disclosure of the Italian priority document.

The District Court also relied on the prosecution history, during which IBSA submitted a dependent claim expressly reciting "semi-liquid," which the District Court interpreted to mean that the applicant did not intend term "half-liquid" in the corresponding independent claim to mean "semi-liquid."

The District Court also considered citations in the patent specification of pharmaceutical references, finding that the term "half-liquid" did not mean "semi-liquid" as understood in the pharmacological arts.  The District Court also interpreted citation to such references to indicate that while the applicant understood the meaning of the term "semi-liquid" it intentionally did not use that term.

Reaching the extrinsic evidence cited by IBSA the District Court was not convinced, terming this evidence "minimally probative" and "unpersuasive."  Proffered dictionary definitions were not in the context of the invention claimed by IBSA, nor were citations to third party patents persuasive to the District Court.  In toto, the District Court held that the term "half-liquid" was not a well-recognized term of art at the '390 patent's earliest filing date.  The final quantum of evidence, from IBSA's expert, was not persuasive to the District Court because it relied on evidence the court had already rejected as unpersuasive.

The District Court rendered a decision on another aspect of its indefiniteness ruling, whether the skilled worker would have understood the term "half-liquid" to be synonymous with "semi-liquid" and finding that it would not.  Indeed, the District Court held in this portion of the opinion that the person of ordinary skill in the art (POSA) would only be able to interpret the term "half-liquid" as used in claim 1 to mean it was "neither a liquid nor a solid."  With regard to the specification, the District Court held that a "half-liquid" would not necessarily have been interpreted by a POSA to be a gel or a paste, based on this portion of the specification:

In particular, said soft capsule contains an inner phase consisting of a liquid, a half-liquid, a paste, a gel, an emulsion or a suspension comprising the liquid (or half-liquid) vehicle and the thyroid hormones together with possible excipients in suspension or solution.

As recited in this passage, "a liquid, a half-liquid, a paste, a gel, an emulsion or a suspension" are all different alternatives and not equivalent to one another as synonyms.

The prosecution history contained but two instances where the applicant distinguished over the prior art on the basis of the composition of the claimed formulation:  in the first, applicant stated that "the claimed invention 'is not a macromolecular gel-lattice matrix'" (emphasis in PFH) and in the second that "the claimed invention is not a 'high concentration slurry.'"  The District Court interpreted these statements to constitute a disclaimer of "some portion of the claim's scope that might otherwise qualify as a half-liquid."

Based on these analyses, the District Court found that asserted claims 1, 2, 4, and 7-9 were held indefinite on the grounds that IBSA's construction lacked support on the intrinsic evidence and there was no basis in the record to construe the claims as IBSA argued.  This appeal followed.

The Federal Circuit affirmed, in a decision by Chief Judge Prost joined by Judges Reyna and Hughes, expressly relying on the Supreme Court's Nautilus v. Biosig Instruments decision.  Analyzing the intrinsic and extrinsic evidence de novo, the panel came to the same conclusions as the District Court.  The panel's analytical framework tracked the District Court's analysis, finding no support for IBSA's claim interpretation in the plain meaning of the claims, the specification, nor the prosecution history.  Particularly with regard to the specification, the panel agreed with the District Court's focus on the listing of alternatives containing the term "half-liquid," as well as another passage that recites "[s]oft capsules (SEC) with liquid, half-liquid, paste-like or gel-like inner phase."  The Federal Circuit rejected other portions of the specification IBSA asserted to be inconsistent with the District Court's and the Federal Circuit's own interpretation, as not establishing boundaries for the term "half-liquid" to render that term with a definite meaning.  The Court also rejected IBSA's assertion that the Italian priority document should be interpreted to render "half-liquid" and "semi-liquid" to be synonymous, based on inconsistencies with how parallel terms were used in that document and the '390 patent specification.  And the panel was persuaded by the dependent claim proffered and then withdrawn during prosecution that used the term "half-liquid" and "semi-liquid" to have separate meanings, as an indication that "the applicant knew the term "semi-liquid" yet elected to use "half-liquid" to mean something different."

Finally, the panel considered the extrinsic evidence "including dictionary definitions, other patents, and expert testimony," and found no error in the District Court's conclusion that this evidence did not rebut the intrinsic evidence.  Indeed, the Federal Circuit used the difficulties IBSA's expert evinced in defining the boundaries of the term "half-liquid" to "demonstrate[] the difficulty a POSA would face in ascertaining" those same boundaries.

Accordingly, the Federal Circuit affirmed the District Court's determination that asserted claims 1, 2, 4, and 7-9 of the '390 patent were invalid under 35 U.S.C. § 112(b) for indefiniteness.

IBSA Institut Biochimique, S.A. v. Teva Pharmaceuticals USA, Inc. (Fed. Cir. 2020)
Panel: Chief Judge Prost and Circuit Judges Reyna and Hughes
Opinion by Circuit Judge Prost