Entering into a stipulation is easy. You say we both agree to move this date or not assert that patent, and normally the court signs it and everyone goes about their business.
Getting out of a stipulation is harder.

If you're wondering just how hard, I present to you Judge Bataillon's opinion this week in Astellas Pharma Inc. v. Zydus, Inc., C.A. No. 20-1589-WCB (D. Del. May 30, 2025).
In that case Judge Bataillon resolved the rare "motion for relief from stipulation." The parties had long ago entered into a case narrowing stipulation in which the defendants dropped their obviousness and anticipation defenses.
Following a trial, then an appeal and a remand, the case was back in Judge Bataillon's hands, and was a bit more complicated. In the interim, it had been consolidated with related cases against other defendants and new claims from a related patent.
Because those other claims and other defendants were not bound by the prior stipulation, Lupin and Zydus argued that it would be unjust and inefficient to prevent them from asserting obviousness against the old patent, whilst allowing them to assert it against a related patent and allowing other defendants to assert obviousness defenses against both.
Judge Bataillon granted the motion, citing a multi-factor test standard I had not seen in a long time:
To decide whether to relieve the Generics Manufacturers of their stipulation the Court may consider: “(1) the effect of the stipulation on the party seeking to withdraw the stipulation . . .; (2) the effect on the other parties to the litigation . . . [and]; (3) the occurrence of intervening events since the parties agreed to the stipulation.” At bottom, this is a discretionary determination.
Id. at 3-4 (quoting Waldorf v. Shuta, 142 F.3d 601, 616 (3d Cir. 1998)) (internal citations omitted).
In particular, the possibility of inconsistent results, and the attendant prejudice to the defendants, weighed in favor of granting the motion:
Maintaining the stipulation in the consolidated case creates two specific risks to the Generics Manufacturers (and Astellas for that matter). One, following the stipulation risks inconsistent results between defendants and patents. Specifically, two defendants, MSN and Ascent, are already raising an obviousness challenge ‘780 Patent. If the Court were to find the ‘780 Patent invalid, it would create an odd situation in which a patent is invalid for one defendant and valid for another. Not only that but Lupin and Zydus are raising an obviousness challenge to the ‘409 Patent, meaning the jury could come to diverging verdicts on what is, for obviousness purposes, the same patent. A divergence between parties and patents would be unfair to the Generics Manufacturers. Two, following the stipulation encourages unproductive satellite litigation. Lupin and Zydus have suggested that if they are not able to proceed here, they will file a new case for declaratory relief—unbounded by the stipulation. And, if Ascent and MSN succeeds at their bench trial or the jury buys Lupin and Zydus’s obviousness arguments, the parties will litigate this issue over again. Finally, if the Court prevents Lupin and Zydus from arguing obviousness and the Federal Circuit reverses, there is a real possibility of a fourth trial on the ‘780 Patent. Overall, following the stipulation engenders a messier procedural environment and wasted resources for all parties, including Astellas. This unfairness supports reliving Lupin and Zydus of their stipulation.
Id. at 5.
So there, now you know what to call your motion next time you want to back out of a stipulation.
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