Maquet Cardiovascular LLC v. Abiomed Inc. et al. (D. Mass 17-cv-12311).

Maquet brought suit against Abiomed, claiming Abiomed infringed a patent covering intravascular blood pumps.  The patent-in-suit disclosed a steerable cannula with a pigtail-shaped distal tip.  This tip assists with the steerability of the cannula, which allows a surgeon to direct the cannula through a patient’s vascular system to the heart.

Abiomed responded with (among other things) an affirmative defense of prosecution laches, and Maquet moved for summary judgment on this issue.

Prosecution laches renders a patent unenforceable when there is an unreasonable and unexplained delay in prosecution that “constitutes an egregious misuse of the statutory patent system.”  A party seeking a prosecution laches determination must show this unreasonable and inexcusable delay and must also show that it suffered prejudice attributable to the delay.  The second of these requires proving intervening rights – investment and work on, or use of, the claimed technology that occurred during the delay.  As a patent is presumed valid, prosecution laches must be proven by clear and convincing evidence.

In this case, Maquet first filed a patent application describing a cannula with a pigtail-shaped distal end in 1999.  A year later, Maquet filed a PCT application to an intra-vascular pump having a guide mechanism that, while it did not mention a pigtailed-shaped end in its specification, referred to steering means identified in the earlier application that was pending at the time the PCT was filed.  A year following the PCT filing, the earlier patent application was abandoned.  Maquet filed subsequent continuations of the PCT, none of which mentioned a pigtail tip.  It was not until 2015 that Maquet filed a continuation application that likewise did not directly reference a pigtail tip.  While that was pending, Maquet sent a cease and desist letter to Abiomed over the patent that resulted from the PCT application, and subsequently amended the claims of the pending application to affirmatively recite a pigtail tip and added the now-abandoned initial application as an appendix to the pending application.  Maquet in 2018 filed yet another continuation application, the one that became the patent-in-suit, and included claims that both did and did not recite the pigtail tip limitation.

Judge Saylor granted Maquet’s motion as to some, but not all, of the asserted claims.  He noted that Federal Circuit precedent did not set any bright-line rules for what constitutes an “unreasonable” delay, and that delay may be unreasonable when an applicant’s competitors are not given notice as to what the applicant is seeking to patent and what they must then design around.  Judge Saylor found that Maquet had complied with the statutory and regulatory requirements in filing its continuation applications, and that an applicant is generally free to broaden claims to cover a competitor’s products so long as the priority filing provided support for the broadened claims.  He also indicated that laches is equitable in nature, and that even if Maquet did comply with the patent laws and PTO rules, if it was actually aware of Abiomed’s investment in a pigtail-ended device in the period between its 2001 PCT filing and its 2016 amendment to claim a pigtail ended cannula, such knowledge would weigh in favor of laches.  As the question of Maquet’s knowledge was in genuine dispute, summary judgment would be inappropriate if Maquet could not demonstrate absence of prejudice from the delay, which hinged on whether Abiomed reasonably was unaware of Maquet’s claim to a pigtail-ended cannula.

Maquet’s priority application never expressly referenced a pigtail end.  While it referred to the earlier (and subsequently abandoned) application, it did not specify that the pigtail end was one of those means.  As that application went abandoned before being published, it was not readily available on the PTO website; however, as it was referenced in a subsequent patent, it could be obtained by requesting it from the PTO and payment of a $15 fee.  Abiomed contended that the lack of reference to a pigtail and the fact that the abandoned application was not readily available to the public made the pigtail feature too difficult to reasonably identify as being potentially covered.  Judge Saylor noted that, while this may be true, the inventor on the Maquet patents went to work for Abiomed in 2007, which suggests that Abiomed would have learned about it at least by that year.  Judge Saylor determined that under the circumstances, there were genuine disputed issues of material fact that precluded summary judgment on the claim that recited the pigtail.  He did find that Abiomed had failed to proffer evidence of laches with respect to the asserted claims that did not recite a pigtail, and granted Maquet’s motion with respect to those claims.