Stent Wars: Cordis Corp v. Boston Scientific Corp., Fed. Cir. (2011)

The Stent Wars

The Court of Appeals for the Federal Circuit (“CAFC”) decision in Cordis Corp v. Boston Scientific Corp., 2011 (“Cordis”), is the latest episode in the ongoing Stent Wars, and provides an example of CAFC review of JMOL verdicts and review of the intent prong of inequitable conduct under the new standard in Therasense.

The Stent Wars involve four major players: Abbott Labs, Boston Scientific, Medtronic, and Johnson & Johnson.  These manufacturers have been engaged in bitter patent lawsuits against each other since the mid 1990s. A stent is a small tubular expanding scaffold that is inserted into a blocked artery during balloon angioplasty surgery.  The stent expands with the balloon and then prevents the artery from collapsing after the surgery is complete. However, many question the medical efficacy of stents in relation to their high cost.  The most recent development in the Stent Wars is that J&J’s stent-manufacturing subsidiary, Cordis, announced it will exit the stent market by the end of this year.

Cordis is the latest ruling in a 14 year lawsuit of Cordis Corp. (“Cordis”) against Boston Scientific Corp and Boston Scientific Scimed, Inc (“BSC”).  In Cordis, the CAFC held that, first, the BSC NIR stent did not literally infringe claim 25 of the Cordis ‘370 patent, and, second, that the Cordis U.S. Patent No. 5,879,370 (‘370) was not unenforceable due to inequitable conduct.

BSC did not literally infringe claim 25 of the ‘370 patent

The CAFC upheld the district court’s finding that the NIR stent did not literally infringe claim 25 in the ‘370 patent.  Slip Op. p. 18.  The district court made this finding in a judgment as a matter of law (“JMOL”).  In making its analysis, “the court (1) determine[d] the scope and meaning of the patent claims asserted, and then (2) the properly construed claims [were] compared to the allegedly infringing device.” Cybor; Slip Op. p. 10.

Scope and meaning of “undulating” in claim 25

The term at issue in claim 25 was “undulating,” where each “cell” along the stent must have “one or more undulating sections . . . generally parallel to the stent’s longitudinal axis.”  The CAFC approved the district court’s definition of “undulating,” wherein the district court used the dictionary and then the prosecution history of the patent to determine the scope and meaning of “undulating.”  Slip Op. pp. 10-15.

First, the Court bound “undulating” to “the ordinary meaning of the language of the jury instruction” because the court’s decision was made in a JMOL.  The Court construed the ordinary meaning of “undulating” using the Webster’s Dictionary definitions of “undulating,” “waves,” “crest,” and “trough.”  From this dictionary analysis, the Court found that “undulating” sections require multiple “waves” with “at least a crest and a trough,”  whereby “the terms ‘crest’ and ‘trough’ . . . implicate changes in direction with the curve extending beyond the point of inflection.”  Slip Op. pp. 11-13.  Under this interpretation, a sinusoidal wave has undulating sections, while a series of semi-circular arches would not.

Second, the district court used the prosecution history of the patent to further refine the scope and meaning of “undulating.”  During prosecution of the parent application of the ‘370 patent, the patentee distinguished their “undulating” structure from the merely curved structures in two other U.S. patents.  Slip Op. 13-14.  This estopped the patentee from arguing that an “undulating” series may only contain either a “crest” or a “trough.”

Claim 25 compared to the allegedly infringing NIR stent

After affirming the district court’s definition of “undulating,” the CAFC applied the properly construed claim 25 from the JMOL to the allegedly infringing NIR stent.  A JMOL is appropriate when “a party has been fully heard on an issue during a jury trial and the court finds that a reasonable jury would not have a legally sufficient evidentiary basis to find for the party on the issue. . .” FRCP 50(a)(1).  Furthermore, the court “must presume that the jury resolved all factual disputes in favor of the prevailing party, and[it] must leave those findings undisturbed as long as they are supported by substantial evidence,” where “substantial evidence requires more than a mere scintilla . . .”

The CAFC held that the NIR stent did not infringe claim 25 of the ‘370 patent.  Slip Op. p. 18.  The Court noted that the NIR stent contained longitudinal member U-loops that included “a trough, but no crest as that term is used in the claim construction.”  Slip Op. p. 17.  The NIR U-loops were, therefore, not part of “undulating” sections.  Moreover, Cordis’s evidence consisted of expert testimony on the construction of “undulating” that was rejected by the Court.  Therefore, the CAFC concluded that Cordis presented no more than a mere scintilla of evidence.

Inequitable conduct was not committed during prosecution of the ‘370 patent

The ‘370 patent issued from a continuation off of U.S. Patent Application No. 08/202,128 (“‘128 application”).  The Court noted that the behavior of the ‘128 application pro se prosecuting inventor and a consulting patent attorney were suspicious.  Slip Op.  pp. 3-7, 22.  They had notice from a European Search Report that a particular U.S. Patent Reference was “relevant,” but they did not disclose that material reference to the USPTO during the prosecution of the ‘128 application.  Ultimately, they did disclose that material reference in an IDS for a continuation patent application, but the reference was “buried” amongst 60 other references.  On the other hand, there were no communications about this reference until after the ‘128 application issued as Cordis’ first patent, and the reference was, in fact, ultimately disclosed to the PTO in the continuation application which eventually issued as the ‘370 patent.

The CAFC did not find that the patent was unenforceable due to inequitable conduct.  Slip Op. p. 22.  After the most recent remand, the district court found that “the inferences argued by the plaintiff are supported by evidence of record and as reasonable as those inferences by defendants,” and “it would be clear error . . . to imbue [plaintiff’s] conduct with deceptive intent on this record.”  Cordis Corp. v. Boston Scientific Corp., 641 F. Supp. 2d 353, 359 (D. Del. 2009). A finding of inequitable conduct requires specific intent to deceive, and under the new Therasense standard, “to meet the clear and convincing standard, the specific intent must be ‘the single most reasonable inference able to be drawn from the evidence.” The district court ultimately concluded that “the evidence cited in support of inequitable conduct is not clearly more compelling than the evidence cited in support of not finding inequitable conduct.  After reviewing the facts, the CAFC held that there was no inequitable conduct because it did not find clear error in the district court’s conclusion.


After this 14-year episode in the Stent Wars, BSC’s NIR stent was found not to infringe Cordis’s ‘370 patent.  Cordis too can claim a victory as its patents retained a presumption of validity, despite being obtained under arguably suspicious circumstances.   The Stent Wars continue to fuel litigation through a stent market that is approaching $8 billion and complicated disputes featuring intricate stent inventions.  In the end, Cordis provides us with recent examples on how the CAFC reviews a JMOL verdict on literal infringement and how the CAFC is currently analyzing inequitable conduct claims under the framework in Therasense.