Claim Construction: A Game of Chance at the Federal Circuit

Dr. Bruce Saffran (“Saffran”) is the owner and sole inventor of U.S. Patent No. 5,653,760 (the “’760 patent”). The ’760 patent describes an apparatus for spurring the repair of bone fractures by containing tissue fragments and tissue growth-promoting macromolecules within the fracture site. A single-layered sheet, which is selectively impermeable to the macromolecules and the tissue fragments, is affixed to the injured bone tissues. The selective barrier properties of the sheet prevent macromolecules from leaking out into neighboring tissues, thus concentrating the macromolecules at the fracture site.

In addition, drugs facilitating tissue regeneration can be bonded via hydrolysable chemical bonds to the inner surface of the single-layered sheet. This inner surface faces the injured tissues. Water molecules present at the fracture site causes lysing of the chemical bonds, which in turn releases and delivers the drugs into the fracture site. Bond lysis occurs at a constant rate, which enables the steady and controlled release of the drugs.

One particular embodiment of Saffran’s invention involves wrapping the single-layered sheet around an intravascular stent. The stent can then be inserted into a blood vessel to repair injured blood vessel wall.

Claim 1 is representative and reads, with emphasis added:

1. A flexible device for implantation into human or animal tissue to promote healing of a damaged tissue comprising:

a layer of flexible material that is minimally porous to macromolecules, said layer having a first and second major surface, the layer being capable of being shaped in three dimensions by manipulation by human hands . . .

the layer having material release means for release of an at least one treating material in a directional manner when said layer is placed adjacent to a damaged tissue,

the device being flexible in three dimensions by manipulation by human hands,

the device being capable of substantially restricting the through passage of at least one type of macromolecule therethrough

Cordis Corporation (“Cordis”), a member of the Johnson & Johnson family of companies, manufactures a drug-eluting coronary stent under the brand name, Cypher^®. The stent comprises a metallic mesh coated with a microscopic layer of polymers. The macromolecular drug, sirolimus, is mixed with the polymer matrix, and is used to prevent plague buildup in coronary arteries. Following implantation of the stent, the drug diffuses out of the stent in a controlled release.

In 2007, Saffran filed suit against Cordis, alleging that Cypher^® infringed the ’760 patent. A particularly contentious issue at trial was the construction of “device” and “release means” as recited in the ’760 patent. After a Markman hearing, the district court first interpreted the term “device” to be non-limiting preamble language that “merely gives a descriptive name to the set of limitations in the body of the claim.” The district court then continued on to construe the term to mean “a device having the limitations called out by the body of the claim.”

Next, the district court addressed the language, “release means for release of an at least one treating material in a directional manner.” The district court first found that the claim language is a means-plus-function limitation invoking 35 U.S.C. §112, sixth paragraph. Then, the district court interpreted function of the claimed “release means” as “releas[ing] a drug preferentially toward the damaged tissue,” and finally defined the corresponding structure disclosed in the specification of the ’760 patent as “chemical bonds and linkages.”

The case proceeded to a jury trial, from which Saffran emerged a rich victor. The jury awarded Saffran a handsome amount upward of $590 million dollars ($482 million in damages, plus over $111 million in interest). At the time, the award was the ninth-largest patent verdict in the U.S. history. Naturally, Cordis appealed. As was the case at the district court, the primary issue on appeal was the correct construction of the claim terms, “device” and “release means.”

I. Claim Construction

1.              “Device”

The Federal Circuit began by faulting the district court for interpreting “device” as merely non-limiting preamble language. Certainly, the district court was correct that term “device” must possess all the limitations set forth in the body of the claims. However, noting the appearance of the term “device” in the body of every claim of the ’760 patent, the Federal Circuit concluded that the term itself required construction beyond the explicitly recited limitations.

Relying primarily on the prosecution history of the ’760 patent, the Federal Circuit then went on to interpret “device” to narrowly mean a continuous sheet.  During prosecution, one of the arguments that Saffran presented to distinguish over the cited art was that unlike the prior art invention, his device is a sheet. This argument, the Federal Circuit found, did not merely illuminate how the inventor understood his invention. Rather, Saffran’s arguments provided an affirmative definition for the term “device.” It is irrelevant that Saffran had also offered other grounds for overcoming the cited art. Indeed, “an applicant’s argument that a prior art reference is distinguishable on a particular ground can serve as a disclaimer of claim scope even if the applicant distinguishes the reference on other grounds as well.”

The Federal Circuit acknowledged that “[t]o be sure, a prosecution disclaimer requires ‘clear and unambiguous disavowal of claim scope.’” However, a clear and unambiguous disavowal need not amount to an applicant’s explicit, affirmative disclaimer. Saffran’s assertion during prosecution that the claimed device is a sheet sufficed to limit “device” as recited in the claims of the ’760 patent to a continuous sheet.

In her concurrence opinion, Judge O’Malley took significant issue with the majority’s construction of the term “device,” opting for the district court’s construction of the term as something which comprises the limitations set out in the body of the claim. Judge O’Malley focused on the fact that the specification of the ’760 patent disclosed several embodiments that demonstrably did notinclude a continuous sheet. Judge O’Malley observed that “while long-winded and rambling at times, the written description provides a broad disclosure touching upon several medical applications and physical structures.” The breadth of the disclosure precluded limiting “device” to the one particular embodiment requiring a continuous sheet structure.

Judge O’Malley also questioned the majority opinion’s reliance on the prosecution history of the ’706 patent. The majority was faulted for elevating prosecution history to a prominence it did not deserve. The Federal Circuit had previously held that prosecution history is less useful than specification for claim construction purposes, because “prosecution history represents an ongoing negotiation between the PTO and the applicant, rather than the final product, [and thus] often lacks the clarity of the specification.” Further, Judge O’Malley acknowledged that while Saffran had unambiguously disclaimed the alternative embodiments disclosed in the cited prior art, she was skeptical as to whether the prosecution history of the ’760 patent convincingly supported the finding that Saffran had also deliberately and unambiguously disclaimed all embodiments which excluded the continuous sheet structure.

2.              “Release means”

On appeal, there was no dispute that the claim language, “release means for release of an at least one treating material in a directional manner,” should be construed as a means-plus-function pursuant to 35 U.S.C. §112, sixth paragraph. The district court’s interpretation of the function of the “release means” was also undisputed.

However, Cordis disagreed with the district court’s identification of the corresponding structure for carrying out the function. Cordis argued that the only corresponding structure for the “release means” identified in the ’760 patent was a hydrolysable bond, and not the generic “chemical bonds and linkages” as determined by the district court. Defending the district court’s interpretation, Saffran contended that one skilled in the art would have recognized “chemical bonds and linkages” as suitable structures for the claimed “release means.” The Federal Circuit ultimately sided with Cordis.

The Federal Circuit articulated that for the purpose of §112, sixth paragraph, a structure disclosed in the specification is a corresponding structure only if the specification or prosecution history clearly links or associates the structure to the function recited in the claim. The Federal Circuit indicated that the specification of the ’760 patent was replete with description of the linkage between the treating material and the sheet as a hydrolysable bond. The specification even distinguished Saffran’s invention over the prior art on the basis of hydrolysable bonds.

However, the specification of the ’760 patent did not link any additional structures to the release function with sufficient specificity to satisfy §112, sixth paragraph. The Federal Circuit noted that the scattered and seemingly indeterminate use of the term “chemical bonds” throughout the specification failed to convey additional, specific corresponding structures separate and apart from hydrolysable bonds.

More importantly, as to Saffran’s contention that a skilled artisan would have understood the range of chemical bonds and linkages that could be used to perform the release function, the Federal Circuit seemed to suggest that such an argument would be an end run around §112, sixth paragraph. The Federal Circuit held that:

“A patentee cannot avoid providing specificity as to structure simply because someone of ordinary skill in the art would be able to devise a means to perform the claimed function. Under §112, ¶ 6, the question is not what structures a person of ordinary skill in the art would know are capable of performing a given function, but what structures are specifically disclosed and tied to that function in the specification” (emphasis added).

Judge Moore’s concurrence opinion agreed with the majority’s interpretation of “device,” but preferred the district court’s construction of the claimed “release means.” Pointing in particular to one passage in the specification of the ’760 patent, which described attaching a treating material “either mechanically or by chemical bond” to a surface of the claimed device, Judge Moore determined that this passage sufficiently associated the claimed “release means” with a chemical bond structure to satisfy §112, sixth paragraph. Judge Moore reasoned that §112, sixth paragraph requires only some link between a generic structural reference and the claimed function understandable to one skilled in the art. Judge Moore seemed to suggest that the majority opinion had the effect of inappropriately and arbitrarily raising the level of specificity necessary to comply with §112, sixth paragraph.

The Federal Circuit’s application of §112, sixth paragraph, in Saffran seems to deviate from the court’s precedents. Traditionally, a specification properly supports a means-plus-function limitation if the corresponding structure of the means-plus-function limitation is disclosed in the specification itself in a way that one skilled in the art will understand what structure will perform the recited function. See, e.g., Amtel Corp. v. Information Storage Devices, Inc., 198 F.3d 1374 (Fed. Cir. 1999). This was also precisely the point of emphasis in Saffran’s arguments.

However, the Federal Circuit now decides that the understanding of the skilled artisan in light of the specification no longer suffices to establish a corresponding structure. Rather, if a structure were to be identified as a corresponding structure, the specification must link or associate that structure with the claimed function with “sufficient specificity.” Yet, the Federal Circuit provides little, if any, guidance on what constitutes “sufficient specificity.” The Federal Circuit also does not explain its reasons for suddenly imposing this apparently heightened, but nebulous, standard. In fact, the “sufficient specificity” requirement seems to pose a catch-22 for patentees. On the one hand, a patentee who describes certain preferred structures in detail risks having the recited means-plus-function claim limitation being interpreted overly narrowly to correspond only to those structures. This was the case in Saffran. On the other hand, a patentee who wishes to reserve a broad claim scope faces either the herculean task of having to describe specifically every possible corresponding structure to the means-plus-function limitation, or the risk of a rejection for indefiniteness under §112, second paragraph. The Federal Circuit’s “sufficient specificity” standard simply does not seem workable.

II. Infringement

Having determined that the district court misconstrued the claimed “device” and “release means,” the Federal Circuit went on to find that Cordis’ Cypher^® stent did not infringe the ’760 patent. The Cypher® stent both lacked a continuous sheet covering the metallic mesh structure and lacked a drug affixed to the stent surface via hydrolysable bonds.

Interestingly, even though each member of the three-judge panel endorsed a different construction for the claim terms in question, all three members reached the same conclusion that the jury verdict for Saffran should be reversed.

Original article can be found here: http://www.ipwatchdog.com/2013/04/26/claim-construction-a-game-of-chance-at-the-federal-circuit/id=39587/