Maquet v. Abiomed — Prosecution Laches Survives on Pigtail Patent Despite 15-Year Delay

Background

This is the second lawsuit between Maquet and Abiomed over a line of intravascular blood pumps. In this round, Maquet sued Abiomed for infringing U.S. Patent 10,238,783 (filed September 2018), which traces its priority back through a 15-year chain of continuation applications to a Patent Cooperation Treaty application filed in September 2000. Claim 24 of the ‘783 patent specifically recites a “pigtail shaped distal tip” for a steerable cannula used in blood pumps.

The underlying prosecution story is the core of Abiomed’s defense. The pigtail feature first appeared in a 1999 application (the “Steerable Cannula Application”) that was abandoned in December 2001. The PCT Application filed in September 2000 did not mention or depict the pigtail, but instead “incorporated by reference” guidability features from the Steerable Cannula Application. Four continuation applications filed over the following 15 years likewise never mentioned a pigtail tip. Only in 2016 — years after Abiomed had developed and begun selling its Impella blood pumps with a pigtail tip (starting in 2003) — did Maquet first amend a pending application to claim the pigtail, copying the abandoned Steerable Cannula Application into an appendix. The ‘783 patent with claim 24 followed in 2018.

Maquet moved for partial summary judgment to strike Abiomed’s prosecution-laches affirmative defense on all asserted claims, including claims 1–3 (which don’t involve the pigtail) and claim 24 (which does).

The Court’s Holding

The court split its ruling. As to claims 1–3, the motion is granted — Abiomed offered no evidence supporting laches on those non-pigtail claims. As to claim 24, the motion is denied — a genuine dispute of material fact exists on both elements of the prosecution-laches doctrine.

Unreasonable delay. Judge Saylor held that a reasonable factfinder could conclude Maquet did not reasonably disclose the pigtail tip when the PCT Application was published in 2001. The published PCT document contained no direct reference to a pigtail; its incorporation-by-reference of the abandoned Steerable Cannula Application was ambiguous, specifying “side lumens” and “deformable materials” as example guidability features without naming pigtail tips. Under 37 C.F.R. § 1.14, the abandoned application was technically available — but only upon written request and a $15 fee to the USPTO, and Abiomed’s expert opined that a due-diligence searcher would have been deterred by the abandoned status. No member of the public requested the Steerable Cannula Application before August 2016. That factual record could support a finding that Maquet’s 15-year delay in affirmatively claiming the pigtail was “unreasonable and inexcusable under the totality of circumstances” as required by Personalized Media Communications v. Apple.

Prejudice. On the second element, the court likewise found triable issues. Abiomed began investing in the pigtail feature in 2003 and has continued ever since, and whether it was “caught unawares” for prejudice purposes depends on whether a reasonable diligence review of the public record would have uncovered the pigtail in the abandoned application. The court noted circumstantial evidence that may cut against Abiomed, including that the named inventor on the original Steerable Cannula Application became an Abiomed consultant in 2007, and that Abiomed’s CTO saw the PCT Application in 2000 but did not request the Steerable Cannula Application. But those are jury questions.

On Google LLC v. Sonos, which Maquet cited for a bright-line rule: the court read Google narrowly. That decision held prejudice cannot exist where the infringer’s investment postdated a published disclosure of the claimed subject matter — but the Google specification actually contained a written description, whereas here the pigtail feature was only reachable through a chain of reference to an abandoned, never-published application. The court distinguished Google on that factual ground.

Key Takeaways

• Prosecution laches is alive and available in 2026. Even under the post-2000 patent-term regime (where patent term runs from the priority date, so delay no longer extends the monopoly), courts continue to treat laches as a meaningful equitable defense where the patentee holds back a claim, watches a competitor build out a product using the feature, and then surfaces the claim after the fact.
• Incorporation-by-reference of an abandoned application is not bulletproof disclosure. Judge Saylor’s opinion highlights that practical accessibility matters: a feature “disclosed” only through reference to an unpublished, abandoned, fee-gated application may not satisfy the reasonable-disclosure bar that defeats laches prejudice.
• Google v. Sonos doesn’t immunize late-surfaced claims. The Federal Circuit’s August 2025 Google decision is not a categorical rule that any pre-investment disclosure wipes out laches prejudice. It is an application of the doctrine to a record where the disclosure was actually in a published patent specification. Different record, different answer.
• What survives for trial. Claim 24 of the ‘783 patent will be tested at trial on the full prosecution-laches record, including Dr. Aboul-Hosn’s move to Abiomed as a consultant in 2007 and Abiomed’s knowledge during its pigtail investment period.

Why It Matters

Maquet v. Abiomed is a useful primer on how to pressure-test a prosecution-laches defense in the modern patent-term era. With the end-of-patent-term no longer directly extended by delay, equitable laches has lost some of its traditional justification — but Judge Saylor’s opinion makes clear that when a patentee lets 15 years and five continuations pass without claiming a feature while a competitor builds its entire product around that feature, the doctrine still has bite. For medical-device and other long-prosecution-horizon industries, the case underlines the strategic cost of keeping claims in reserve.