By Kevin E. Noonan —

Early last month, the Federal Circuit addressed an important question regarding the interplay between a decision to institute inter partes review before the Patent Trial and Appeal Board and the ultimate determination by the Board regarding whether claims are invalid for the reasons contained in the petition, in TriVascular v. Samuels.

The IPR involved U.S. Patent No. 6,007,575, which claimed intraluminal stents, particularly vascular stents, and specifically such stents that can be "affixed" to vascular walls using an inflatable cuff (designated 17 in this drawing):

wherein the cuff can inflate and deflate by introducing or withdrawing fluid into circumferential ridges 25.

Claim 1 is representative:

1.  An inflatable intraluminal stent adapted to be secured to the interior of a tubular structure within the human body comprising:
    a) an inflatable and deflatable cuff of generally hollow cylindrical continuation having a collapsible lumen, an inner surface, an inlet, an outlet and a friction enhancing outer surface, said friction-enhancing outer surface featuring inflatable protrusion(s) including at least one circumferential ridge disposed about the inflatable cuff, said friction-enhancing outer surface engaging the interior of the tubular structure without penetration to prevent the cuff from moving in a longitudinal direction with respect to the tubular structure when said cuff is in a fully inflated condition;
    b) means for injecting an inflation material into said cuff to inflate it; and
    c) a valve integral with the inflatable cuff for permitting entry of the inflation material from the means for injecting and thereafter sealing said cuff to prevent deflation.

TriVascular filed its IPR petition in response to an infringement action by Samuels, with the Board instituting the IPR on obviousness grounds over the combination of an earlier Samuels patent (U.S. Patent No. 5,423,851) in view of a patent to Todd (U.S. Patent No. 5,423,745) and separately over the combination of a patent to Lazarus (U.S. Patent No. 5,693,088) and the Todd patent.

At the initiation stage, the PTAB construed the term "circumferential ridge" to mean "raised strip disposed circumferentially about the outer surface of the inflatable cuff."  Under that construction, the Board held that the Samuel's '851 patent did not teach away from the circumferential ridges taught in the '575 patent by teaching "penetrating anchoring barbs" and also that removing the barbs (by substituting the circumferential ridges) would not "destroy the objective" of the '851 patent.

Nevertheless, the Board held that TriVascular had not carried its burden of showing the claims to be obvious by a preponderance of the evidence.  Specifically, the Board further construed the term "inflatable protrusions" to mean "protrusions that are themselves inflatable, i.e., expandable by being filled with fluid" and that these were not disclosed in the prior art (nor would there be a motivation to combine the art to achieve the invention claimed in the '575 patent).  The Board also found that, under its construction the circumferential ridges were continuous and cannot be discontinuous inflatable protrusions as disclosed in the cited art.  Under its claim construction and in view of expert evidence adduced during trial, the Board held that TriVascular had not carried its burden that the claims were obvious by a preponderance of the evidence.

The Federal Circuit affirmed, in a decision by Judge O'Malley, joined by Judges Moore and Wallach.  The Court applied de novo review to the ultimate question of obviousness but deferred to the Board on it factual determinations.  With regard to the Board's claim construction, the Court noted that the Board had used the broadest reasonable interpretation standard in assessing whether the ridges should be construed to include discontinuous embodiments.  Specifically, the opinion noted that it is not reasonable to construe individual words in a claim out of context (i.e., as would be understood to be the ordinary and customary meaning of the term to one of ordinary skill in the art).  In reaching its factual determinations, the Board relied upon the specification and dictionary definitions, from which it held that TriVascular's reading that the claims encompasses "discontinuous" circumferential ridges was inconsistent with the customary and ordinary meaning of the term.  (In an amusing sidenote, the opinion recited that TriVascular alluded to the Blue Ridge Mountains to illustrate that a "ridge" can be discontinuous; the panel first gently castigated the petitioner for not providing any basis for imputing a "topological or cartographical" definition of the word, and in a footnote finding that the meaning of Blue Ridge Mountain did not use the word "ridge" to modify the word "mountain.")  The panel also noted in a footnote that it was issuing its decision rather than await the Supreme Court's decision in In re Cuozzo Speed Tech. LLC v. Lee, because TriVascular was arguing for a broader rather than narrower construction.

TriVascular also argued the existence of prosecution history disclaimer, on the ground that during prosecution Samuels distinguished its '851 prior art patent based on continuous inflatable ridges but that the word "continuous" was not in the claims as granted.  The Board found that the claims were deemed allowable after further amendment and prosecution ignored by TriVascular and that omitting the word "continuously" in favor of the phrase "at least one circumferential ridge disposed about the inflatable cuff" was not "clear and unmistakable" disclaimer.  As reviewed by the Court, TriVascular bore the burden of showing "clear and unmistakable" disclaimer in order to prevail, citing Elbex Video, Ltd. v. Sensormatic Elecs. Corp., 508 F.3d 1366, 1371 (Fed. Cir. 2007).

The Court agreed with the Board that TriVascular had not met this burden, saying that the "continuous" limitation was one of several Samuels offered to distinguish over the prior art and that the Examiner never adopted this amendment as the basis for allowing the claims (indeed, the panel understood that the Examiner allowed the claims in view of amendments other than the "continuous" amendment).  The panel also rejected TriVascular's argument that, to overcome prosecution history disclaimer "there must be 'written evidence' to contradict an applicant's concessions made in an amendment, and that '[w]here the record is devoid of any written documentation, no inferences can be made as to what the examiner relied upon or understood,'" purportedly relying on Litton Systems, Inc. v. Whirlpool Corp., 728 F.2d 1423 (Fed. Cir. 1984); Genzyme Corp. v. Transkaryotic Therapies, Inc., 346 F.3d 1094 (Fed. Cir. 2003); and Rohm & Haas Co. v. Crystal Chemical Co., 722 F.2d 1556 (Fed. Cir. 1983), calling that reliance "misplaced."  The opinion states in this regard that this case did not involve nondisclosure of the contents of an examiner interview (Litton), nor introduction of a last-minute amendment that omitted a limitation that had been relied upon throughout prosecution (Genzyme), nor a charge of inequitable conduct based on intentional misrepresentations (Rohm), and thus none of this precedent supported TriVascular's argument.

Turning (at last) to the obviousness issue, the panel found no error in the Board's distinguishing the claimed invention from the prior art.  The Samuels '851 patent disclosed stents comprising inflatable protrusions containing penetrating spikes illustrated in Fig.3 (inflated) and Fig.4 (deflated) of the patent:

while the Todd patent showed "non-penetrating 'gripping protuberances' on the outer surface of the stent," illustrated in Fig.7 (wherein the panel noted these protuberances were solid instead of inflatable:

For the panel, "a key point of distinction between the '575 patent and the prior art is that the '575 patent teaches the use of inflatable, circumferential ridges that do not penetrate the vessel wall" (emphasis in opinion).  The Court agreed with the Board's decision that TriVascular had not carried its burden of showing obviousness based, inter alia, on its understanding that substituting the barbs in the Samuels '851 patent with the ridges from the Todd patent "would destroy the basic objective of the barbs, which is to penetrate the surrounding tissue" (emphasis in opinion).  This in view of other distinctions (such as that the Todd patent's ridges are not inflatable) convinced the Court that there was substantial evidence supporting the Board's decision that TriVascular had not established obviousness for the claims at issue.

The most significant portion of the opinion involves the panel's rejection of TriVascular's argument that, having decided to implement the IPR, the Board was under an obligation to explain its "inconsistent" decision that the claims were not obvious:

Contrary to TriVascular's assertions, the Board is not bound by any findings made in its Institution Decision.  At that point, the Board is considering the matter preliminarily without the benefit of a full record.  The Board is free to change its view of the merits after further development of the record, and should do so if convinced its initial inclinations were wrong.  To conclude otherwise would collapse these two very different analyses into one, which we decline to do.  If those determinations were somehow binding with respect to the Board's final decision, as TriVascular urges, the patentee's appeal rights as to that second determination would be close to illusory.  TriVascular's argument also fails to appreciate that there is a significant difference between a petitioner's burden to establish a "reasonable likelihood of success" at institution, and actually proving invalidity by a preponderance of the evidence at trial.  Compare 35 U.S.C. § 314(a) (standard for institution of inter partes review), with 35 U.S.C. § 316(e) (burden of proving invalidity during inter partes review).  The Board's findings in its Final Written Decision were thus not inconsistent with those in its Institution Decision; they were made under a qualitatively different standard (emphasis in opinion).

These differences in the record supporting the Board's nonobviousness determination included expert testimony and an appreciation that the art provided no basis for substituting just the barbs in the Samuels '851 patent with the protuberances of Todd, particularly because even if substituted the Todd protuberances would not satisfy the limitation that the circumferential ridges be inflatable.

TriVascular, Inc. v. Samuels (Fed. Cir. 2016)
Panel: Circuit Judges Moore, O'Malley, and Wallach
Opinion by Circuit Judge O'Malley

By Kevin E. Noonan —

Last Thursday, the Federal Circuit handed down its non-precedential decision in Purdue Pharma v. Depomed, reviewing the decision of the Patent Trial and Appeal Board on three related inter partes reviews.  While not quite a unicorn, the PTAB decision was unusual in that it affirmed the validity of all claims at issue over a challenge for obviousness.

The challenged patents, U.S. Patent Nos. 6,340,475 and 6,635,280, claimed "controlled-release oral dosage form[s] of a soluble drug and a method of use thereof," which comprised drug dispersed within a solid polymeric matrix.  Such dosage forms were structured so that, after administration, the matrix would swell in the stomach (from absorbing water) and as a consequence remain in the stomach in the presence of food.  As a result, release of the drug from the matrix and adsorption by the body is delayed, which reduces the risk of overdose and controls drug dosage over an extended period of time at safer and more effective levels.

The three IPRs were directed to the following claims, all asserted to be invalid for obviousness:  (1) claims 1, 8–10, 13–15, 43, 45, and 46 of the '280 patent; (2) claims 1, 8–10, 13–15, 61, and 62 of the '475 patent; and (3) claims 43, 54, 55, 57, 58, and 66 of the '475 patent.  Claims 1 and 43 of the '475 patent are representative:

1.  A controlled-release oral drug dosage form for releasing a drug whose solubility in water is greater than one part by weight of said drug in ten parts by weight of water,
    said dosage form comprising a solid polymeric matrix with said drug dispersed therein at a weight ratio of drug to polymer of from about 15:85 to about 80:20,
    said polymeric matrix being one that swells upon imbibition of water thereby attaining a size large enough to promote retention in the stomach during said fed mode ["the swelling limitation"],
    that releases said drug into gastric fluid by the dissolution and diffusion of said drug out of said matrix by said gastric fluid,
    that upon immersion in gastric fluid retains at least about 40% of said drug one hour after such immersion and releases substantially all of said drug within about eight hours after such immersion,
    and that remains substantially intact until all of said drug is released ["the substantially intact limitation"].

43.  A method of administering to a subject a drug that is therapeutic to said subject when absorbed in the stomach where said drug has at least one ionized group in the pH range 5 through 8,
    said method comprising orally administering to said subject a dosage form of said drug while said subject is in a fed mode,
    said dosage form comprising a solid polymeric matrix with said drug dispersed therein at a weight ratio of drug to polymer of from about 0.01:99.99 to about 80:20,
    said polymeric matrix being one that:
    (a) swells upon imbibition of gastric fluid to a size large enough to promote retention in the stomach during said fed mode ["the swelling limitation"],
    (b) releases said drug into gastric fluid by the dissolving of said drug by said gastric fluid and either erosion of said matrix or diffusion of said dissolved drug out of said matrix,
    (c) retains at least about 40% of said drug one hour after such immersion in gastric fluid,
    (d) releases substantially all of said drug within about ten hours after such immersion, and
    (e) remains substantially intact until all of said drug is released ["the substantially intact limitation"],
    thereby extending the release rate of said drug with time during said fed mode while releasing substantially all of said drug within said stomach where said drug is maintained in an acidic environment.

Petitioner Purdue Pharma asserted several prior art references, only two of which were relevant to the PTAB's decision and reviewed by the Federal Circuit:  a scientific journal article by Baveja et al., Zero-Order Release Hydrophilic Matrix Tablets of β-Adrenergic Blockers, 39 Int'l J. Pharmaceutics 39 (1987) ("Baveja"), and U.S. Patent No. 5,582,837 ("Shell").

The PTAB held that Purdue had failed to establish that the claims were invalid for obviousness by a preponderance of the evidence, the Board standard in IPRs.  It agreed with Purdue that the Baveja reference disclosed delayed release drug formulations but failed to disclose the "swelling" and "substantially intact" limitations, and that the Shell patent disclosed drug formulations comprising these missing limitations.  Nevertheless, the Board held that Purdue failed to show that the art provided "a reasoned basis for combining these references with a reasonable expectation of success" at achieving the claimed formulations.  Specifically, the Board held that Purdue had failed to show the "how or why" the skilled worker would have combined the features from the Shell patent in the Baveja formulation.  In addition, the PTAB held that insofar as the motivation to combine the cited references was determined by the problem to be solved it constituted hindsight reconstruction and thus was not a proper basis for finding the claims to be obvious.

In addition, the Board found that Purdue had not established that there would have been a reasonable expectation by the skilled worker of success, based on expert testimony proffered by the patentee on the number of variables involved in combination with inventor testimony regarding how long it had taken to achieve the claimed formulation.  In addition, the Board held that Purdue had not shown that adding the swelling and substantially intact features would not change the other properties of the formulation.

The Federal Circuit affirmed, in an opinion by Judge Lourie, joined by Chief Judge Prost and Judge Newman.  The Court reviewed the Board's legal conclusion of obviousness de novo and its factual determinations for substantial evidence (citing In re Gartside).  Moreover, concerning the questions before it, the panel stated that "the determinations of what a reference teaches and the existence of a reason to combine references are questions of fact," citing In re Beattie, 974 F.2d 1309, 1311 (Fed. Cir. 1992), and In re Hyon, 679 F.3d 1363, 1365–66 (Fed. Cir. 2012).  The opinion agreed that there was substantial evidence supporting the Board's determination that "each limitation of the challenged independent claims was known in the art, as evidenced by the teachings of Baveja and Shell."  However, the Court also agreed that Purdue bore the burden of showing that the skilled worker had a reason to combine these teachings and have had a reasonable expectation of success, citing PAR Pharm., Inc. v. TWI Pharm., Inc., 773 F.3d 1186, 1193 (Fed. Cir. 2014).  The Court credited the expert opinion relied upon by the Board that the teachings of the cited references were "interrelated," but found that Purdue "did not explain in sufficient detail how or why a skilled artisan would have been motivated to combine the 'swelling' and 'substantially intact' features of the Shell formulation with the Baveja formulation to attain the claimed dosage form."  Regarding the Board's hindsight determination, the Court found that "[Purdue] failed to demonstrate to the Board that the problem was known in the art or that Purdue's formulation of the problem was derived directly from the prior art, rather than from the challenged claims," citing Insite Vision Inc. v. Sandoz, Inc., 783 F.3d 853, 859 (Fed. Cir. 2015), for the proposition that "[d]efining the problem in terms of its solution reveals improper hindsight in the selection of the prior art relevant to obviousness."  The panel also agreed with the Board that Purdue had failed to show that the skilled worker would have expected that modifying the dosage formulation disclosed by Baveja to incorporate the features of the Shell patent would not affect (presumably negatively) the "other desired properties" of the patented formulation.

While being of limited significance (constrained by its facts and lacking precedential value), the case may provide some comfort that the PTAB can in the right circumstances uphold the validity of a pharmaceutical claim challenged for obviousness with sufficient legal support to be affirmed by the Federal Circuit.

Purdue Pharma L.P. v. Depomed, Inc. (Fed. Cir. 2016)
Nonprecedential disposition
Panel: Chief Judge Prost and Circuit Judges Newman and Lourie
Opinion by Circuit Judge Lourie