The Leahy-Smith America Invents Act prescribed two very different post-grant review proceedings in U.S. patent law.  The first, post-grant review (PGR), had some analogies with European opposition practice, in that petitions for PGR could be filed no later than nine months after the patent had granted and any ground of patentability was available as the basis for challenge (see 35 U.S.C. § 321 et seq.).  The other proceeding, inter partes review (IPR), was available throughout an unexpired patent term but the subject matter of challenge was limited to anticipation under 35 U.S.C. § 102 and obviousness under 35 U.S.C. § 103 (see 35 U.S.C. § 311 et seq.).  However, Section 112 issues can be considered in an IPR as a part of construing the claims when questions of priority are raised, and this was the basis for the Patent Trial and Appeal Board (PTAB) to find invalid all but one of the challenged claims in Indivior UK Ltd. v. Dr. Reddy's Laboratories S.A.

Dr. Reddy's petitioned for inter partes review (IPR) of U.S. Patent No. 9,687,454 on the grounds that all claims were anticipated by U.S. Patent Publication 2011/0033541 to Myers.  The claims are directed to therapeutic agent-containing films that can be orally dissolved as an administration route for various medicines.  The '454 patent is the latest in a series of related applications, the earliest (U.S. Patent Application 12/537,571) dating to 2009.  At issue in this IPR was whether the challenged claims were entitled to this earliest filing date, which antedated the publication of the '541 application asserted by Dr. Reddy's for anticipation.

The opinion sets forth claims 1, 7, 8, and 12 as representative of the issues before the Board.

Claim 1:

1.  An oral, self-supporting, mucoadhesive film comprising:
    (a) about 40 wt % to about 60 wt % of a water-soluble polymeric matrix;
    (b) about 2 mg to about 16 mg of buprenorphine or a pharmaceutically acceptable salt thereof;
    (c) about 0.5 mg to about 4 mg of naloxone or a pharmaceutically acceptable salt thereof; and
    (d) an acidic buffer;
    wherein the film is mucoadhesive to the sublingual mucosa or the buccal mucosa;
    wherein the weight ratio of (b):(c) is about 4:1;
    wherein the weight ratio of (d):(b) is from 2:1 to 1:5;
and
    wherein application of the film on the sublingual mucosa or the buccal mucosa results in differing absorption between buprenorphine and naloxone, with a buprenorphine Cmax from about 0.624 ng/ml to about 5.638 ng/ml and a buprenorphine AUC from about 5.431 hr*ng/ml to about 56.238 hr*ng/ml; and a naloxone Cmax from about 41.04 pg/ml to about 323.75 pg/ml and a naloxone AUC from about 102.88 hr*pg/ml to about 812.00 hr*pg/ml.

7.  The film of claim 1, wherein the film comprises about 48.2 wt % to about 58.6 wt % of the water-soluble polymeric matrix.

8.  The film of claim 7, wherein the film comprises about 48.2 wt % of the water-soluble polymeric matrix.

12.  The film of claim 1, wherein the weight ratio of (d):(b) is from about 1:1 to 1:5; wherein the weight ratio of (b):(a) is from about 1:3 to about 1:11.5; and wherein the film comprises about 48.2 wt % to about 58.6 wt % of the water-soluble polymeric matrix.

(emphasis in each instance in the opinion).  As is evident from the emphasized limitations, the distinction between claim 8 and the other claims is that this claim has a particularly specified composition of the water-soluble polymeric matrix making up the film while the other claims have a broader range of values for this parameter.

The Board considered whether the written description in the '571 priority specification had support for these features.  The Board found express disclosure for the "about 48.2 wt %" limitation in the '571 specification (albeit as the result of calculation by the skilled artisan); the Tables containing these data were reciprocated in the Federal Circuit opinion.  (While express disclosure of a claimed range can readily satisfy the written description requirement, inherent disclosure of such ranges by example is also in some cases adequate for written description purposes; see Union Oil of Cal. v. Atl. Richfield Co., 208 F.3d 989, 997 (Fed. Cir. 2000)).  The ranges of water-soluble polymer in the films recited by the other claims did not find support in the '571 specification, according to the Board.  Moreover, the Board did not find Indivior's expert witness testimony to be credible on this issue.  Finally, the Board held that a person of ordinary skill in the art "would have been led away" from these ranges based on the '571 disclosure that "[t]he film may contain any desired level of self-supporting film forming polymer."  Accordingly, the Board held that the challenged claims of the '454 patent were not entitled to the priority date of the '571 application and thus claims 1-5, 7, and 9-14 were invalid for being anticipated by the teachings of the prior art '541 application while claim 8 was not anticipated.  Both parties appealed the Board's judgment.

The Federal Circuit affirmed, in an opinion by Judge Lourie joined by Judge Dyk and joined in part by Judge Linn, who dissented in part.  Regarding Indivior's appeal of the Board's invalidation of claims 1-5, 7, and 9-14, the panel majority agreed with the Board that the portions of the '571 specification Indivior attempted to rely upon did not disclose, expressly or inherently, the ranges recited in claims 1-5, 7, or 9-14.  Instead, there are instances in the disclosure that are "only specific, particular examples" but they are not ranges according to the opinion.  The panel majority expressly rejected Indivior's argument that written description is adequate when the skilled worker would need to "pluck[] out the polymer components and create[] a range from the percentage totals" which the opinion states "amounts to cobbling together numbers after the fact."  And "[a] written description sufficient to satisfy the requirement of the law requires a statement of an invention, not an invitation to go on a hunting expedition to patch together after the fact a synthetic definition of an invention" because "a patent is not a hunting license," citing (with some irony) Brenner v. Manson, 383 U.S. 519, 536 (1966).  The Federal Circuit illustrated the doctrinal difficulties of applying the written description requirement consistently by rejecting Indivior's resort to its case law by stating "written description cases are intensively fact-oriented, and the cases vary, just as ranges vary."

Because Indivior did not dispute that the '541 application would anticipate claims 1-5, 7, and 9-14 if the '454 patent was not entitled to the priority date of the '721 application, the Court affirmed the Board's decision that these claims were invalid for being anticipated.

Turning to Dr. Reddy's cross-appeal, the panel understood the argument to be that the skilled worker "would not have immediately discerned that the '571 application discloses a polymer component comprising 48.2 wt % of a film because the tables do not state the total polymer weight of various formulations."  The panel agreed with Dr. Reddy's that the 48.2 wt% is not expressly disclosed but deferred to the Board's fact-finding as being supported by substantial evidence.  To the possibility that this decision be perceived as being contrary if not contradictory to the Court's decision affirming invalidity of the other claims in the '454 patent, the opinion states that "given that claim 8 does not recite a range, but only a specific amount, which can be derived by selection and addition of the amounts of selected, but identified, components, we accept that there is substantial evidence to support the Board's decision concerning claim 8" and accordingly affirmed.

Judge Linn's dissent illustrated the difficulties of analyzing compliance with the written description requirement.  Citing some of the same caselaw Indivior unsuccessfully relied upon, including Nalpropion Pharms., Inc. v. Actavis Labs. FL, Inc., 934 F.3d 1344 (Fed. Cir. 2019), and In re Wertheim, 541 F.2d 257 (C.C.P.A. 1976), Judge Linn contended the majority was incorrect in failing to find written description support in the '571 specification for the '454 patent's claims 1-5, 7, and 9-14, saying the panel majority had "applie[d] an overly demanding standard for written description for ranges" contrary to this precedent.  His dissent then performs the Judge's assessment of the '571 disclosure and comes to a conclusion opposite from the panel majority.  In Judge Linn's assessment, the reason for this difference with the panel majority is that Judges Lourie and Dyk took statements in the specification out of context and considered the specification to contain "inconsistent language" that Judge Linn is at a loss to perceive.  Indeed, Judge Linn chides the panel majority for doing just what the majority opinion states should not be done, applying "strict rules" to show possession of the claimed range(s).  Judge Linn also states that in his analysis the Tables set forth in the '571 application (and reproduced in the opinion) disclose the 48.2 wt% and 58.6 wt% in the recited ranges and required no "cobbling together numbers after the fact" as the majority had asserted in support of their decision.  Finally, Judge Linn found the Wertheim and Nalpropion opinions to be "directly on point" and support his opinion that the '571 specification provided an adequate written opinion of the challenged claims of the '454 patent.

Indivior UK Ltd. v. Dr. Reddy's Laboratories S.A. (Fed. Cir. 2021)
Panel: Circuit Judges Lourie, Linn, and Dyk
Opinion by Circuit Judge Lourie; opinion concurring in part and dissenting in part by Circuit Judge Linn