Boston Scientific Stent Patent Survives Interference, Endosystems Patents Do Not

Scott Daniels | August 30, 2011

Interference practice has long enjoyed a reputation for requiring precise attention to detail and complete adherence to its rules.  That reputation can only be enhanced by the PTO’s ruling yesterday in Roubin v. Burmeister (Patent Interference No. 105,794), the real parties-in-interest being Endosystems and Boston Scientific, respectively. 

The interference was suggested by Boston Scientific – specifically, an interference between its claims in Application No. 09/427,291 and the claims of Endosystems’ U.S. Patent Nos. 5,827,321, 6,106,548 and 6,475,236.  The PTO later declared the interference, defining the interfering subject matter in the form of an alternative count: stents according to claim 1 of Endosystems’ 321 patent or claim 22 of Boston Scientific’s ‘291 application.  Thus, the party that could prove that it was the first to invent a stent within the scope of the alternative count would win the interference, whereas the claims of the losing party would be rejected or canceled. 

The PTO declared Boston Scientific to be the “senior party,” i.e., Boston had an earlier invention date than the “junior party” Endosystems.  Endosystems did not dispute this point, and the PTO determined that Endosystems “has in essence conceded priority” to Boston. 

Endosystems’ strategy was to file a motion that certain claims in its ‘321 patent and all the claims of its ‘548 and ‘236 patents did not “correspond to the count.”  Endosystems argued that the identified claims of those three patents recited inventions that were “patentably distinct” from the count, and therefore those claims should not be part of the interference.  Even if Boston Scientific won the priority contest in the interference, argued Endosystems, the identified claims of the Endosystems’ patents should survive.

The party filing a motion to “designate claims as not corresponding to the count” bears the burden of proof: it must show that the claims would not have been anticipated or rendered obvious by the count.  In other words, the moving party is required to establish that the claims-in-question are patentably distinct from the count as if the count were a prior art reference, considered in light of other prior art references, as well as the skill in the art. 

Here, Endosystems separated its claims-in-question into nine groups and asserted that the claims in each group recited a limitation that was not found in the count.  The PTO agreed and found that Endosystems’ claims were not anticipated by the count.  The PTO also found, however, that Endosystems had failed to establish that its claims were not obvious over the count.  Addressing the motion as a whole, the PTO criticized Endosystems for not considering the level of skill in the art.  Further, Endosystems “discusses only the prior art of record and makes no representation that it is unaware of any prior art which discloses the various features [that] it alleges [are] missing from the subject matter of the count.”  The PTO added that “[f]or that reason alone, [Endosystems’] motion is inadequate.” 

The PTO then addressed individually each of the limitations that Endosystems had asserted was absent from the count or the prior art of record.  In each instance, the PTO found Endosystems’ arguments to be unconvincing, often finding that that the distinction asserting would have been an obvious choice for one skilled in the art.  For one set of claims, the PTO concluded that Endosystems “responds only to arguments made in [Boston Scientific’s] suggestion for interference, rather than establishes independently, as it should, that the claims are patentably distinct from the count.  That seriously undermines the motion for which [Endosystems] bears the burden of proof.” 

The moral, of course, is that interference practice is unforgiving and that a party must thoroughly address every aspect of an issue on which it bears the burden of proof.

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