A Blog About Intellectual Property Litigation and the District of Delaware


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This is not the level of disclosure at issue here.
This is not the level of disclosure at issue here. AI-Generated, displayed with permission

Most readers who are patent litigators will know this already, but a "claim chart" is a table with two columns. The column on the left lists claim elements, and and the column on the right lists the portions of something—typically a product, system, or disclosure—that meets the elements on the right.

The chart shows the reader how the thing (whatever it may be) meets the elements of a claim or claims.

Detailed claim charts sometimes include figures with arrows pointing to the relevant claim elements, quotes of relevant text (if applicable), and/or a narrative description of how the cited material meets the element.

Of course, one …

No Stopping
Ben Tofan, Unsplash

As most of our readers likely know, IPR estoppel means that an accused infringer who brought an IPR cannot claim invalidity at trial on a grounds it reasonably could have raised during the IPR. But what constitutes a "grounds" for invalidity has varied across different District Court judges.

Everyone agrees that, as the statute says, the PTAB cannot address system or product prior art under the on-sale bar, but can potentially address publications describing those products. There has long been a split of precedent on whether an accused infringer covered by IPR estoppel can argue invalidity based on a prior art product, where the documentation describing the production could have been asserted in the IPR …

Ping Pong
Jure Zakotnik, Unsplash

We had some indications last fall that referrals to visiting judges may be slowing—but six months on, it's clear that they are still ongoing. This week, we saw 11 cases reassigned to visiting Judge Campbell Barker of the Eastern District of Texas. That prompted me to take a look at recent referrals in patent cases, and here is what I saw for this year:

  • May 6, 2025: 11 reassignments to visiting Judge Campbell Barker, E.D. Tx.
  • April 8, 2025: 11 reassignments to visiting Judge Choe-Groves, United States Court of International Trade
  • March 11, 2025: 9 reassignments to visiting Judge John F. Murphy, E.D. Pa.
  • February 12, 2025: 7 reassignments to visiting Judge Joshua D. Wolson, E.D. …

As we've covered exhaustively, Delaware favors the use of contention interrogatories. As discovery requests go, these are often some of the more burdensome ones to deal with, and so the responding party will frequently respond with all manner of possible objections.

One response that I see from time to time is that a contention topic seeks information that is really the subject of an expert report, and thus that no response is necessary until the reports are due.

This is where expert reports come from
This is where expert reports come from AI-Generated, displayed with permission

This was exactly the approach that the defendant took last week in Astellas Pharma Inc. et al v. Sandoz Inc., C.A. No. 20-1589-JFB-EGT, D.I. 779 (D. Del. May 6, …

Watcha got there? New ADR provision?
Watcha got there? New ADR provision? Zdeněk Macháček, Unsplash

It's always a good idea to keep up to speed on the judges' form scheduling orders. In their form orders, the judges set forth their preferences, and when those orders are entered in a case, they can override some of the local rules.

In the past, when the judges have updated their form scheduling orders, they have occasionally ordered that the updates to apply to pending cases. Sometimes, even absent such an order, counsel have been eager to apply the new procedures on their own.

(The last such change I recall was when judges started switching over to Judge Andrews' method of claim construction briefing, where the parties serve back-and-forth …

Roll the Dice
Leon-Pascal Janjic, Unsplash

We haven't written about pre-institution IPR stays in some time. Defendants generally know that they are tough to achieve. You can try it but, unless there is something special about your case, pre-institution stays are rare. Most of our judges view the chances of institution as too remote to support a stay, and want to evaluate the situation after institution.

Judge Andrews issued a short oral order last week consistent with that view, denying a pre-institution in a way that suggests, unsurprisingly, that getting a pre-instutition stay remains difficult:

I read the briefs in connection with the motion to stay. Each side's positions are clear. Oral argument would not change the outcome. Therefore, the oral argument …

As the wise man said, pobody's nerfect. Although it may be hard to fathom, even I dear, reader have made a typo once or twice. I recall clearly the last time, it was autumn of 2003 . . .

(Eds. Note -- he goes on like this for a while, so I cut it out. his actual last typo was in this blog on Tuesday.)

Pictured: the author
Pictured: the author AI-Generated, displayed with permission

Even in the law this is usually no big deal -- you realize you submitted the wrong exhibit Q, or you forgot the signature line, or whatever, and as long as you catch it early it tends to be fixable with a call to opposing counsel and the …

I've been a Delaware lawyer for a while now, but today is the first time I've seen a case where a party submitted video evidence of a deponent acting suspicious.

Pictured: The deponent, probably
Pictured: The deponent, probably Sergiu Nista, Unsplash

I gather from the briefing that the case was already quite contentious, as the plaintiff in Inpria Corporation v. Lam Research Corporation, C.A. No. 22-1359-CJB, D.I 506 (D. Del. Apr. 28, 2025) had requested a deposition "focused solely on document creation, retention and storage." Id. at D.I. 293. According to the briefing, the deponent "referenced another screen, positioned to his left, after questions were asked but before providing an answer," but when asked about what was on the screen, he testified …

Never-before-seen photo of Mark Twain issuing his famous quote about statistics.
Never-before-seen photo of Mark Twain issuing his famous quote about statistics. Emily DiBenedetto, displayed with permission

The Administrative Office of the U.S. Courts prepares various statistical reports on behalf of the Federal Judiciary, including the Federal Court Management Statistics, which are released quarterly. The most recently released batch of data comes from December 31, 2024. You might see these data cited occasionally in motions to transfer, as I happened to notice in a District of Utah opinion denying a motion to transfer to the District of Delaware.

The first trend is that—surprise!—our judges are very busy.

There have been an average of nearly 2,400 pending cases at any given time over the last six years, and total District of …

You know what to do...
You know what to do... AI-Generated, displayed with permission

Many District of Delaware scheduling orders in patent cases include deadlines for both "initial" and "final" infringement and invalidity contentions. In those cases, parties often argue that having a deadline for "final" invalidity contentions means there is no obligation to supplement in the period between initial and final contentions.

The obligation to supplement under Federal Rule of Civil Procedure 26, after all, states that it applies to Rule 26(a) disclosures, interrogatories, RFAs, and RFPs—but not explicitly to "contentions" required by a scheduling order.

I've seen the Court go both ways on this. The judges often seem willing to grant a motion to compel earlier responses, saying that early supplementation is required …