There is a lot of precedent in D. Del. regarding when the parties can and can't present evidence from post-grant patent proceedings such as IPRs. Most often, the Court holds that such evidence is inadmissible or constrained, to prevent it from unduly influencing the jury. "We already won this once" can be a powerful argument.
Last week, Judge Williams issued an opinion taking the usual position as to most evidence. But the Court also held that simply asserting a prior art reference that was raised in post-grant proceedings opens the door for the patentee to introduce evidence from those proceedings:
Zynga's MIL #3 seeks to exclude argument, evidence, or testimony regarding post-grant Patent Office Proceedings. . . . IBM notes that it intends to show the jury that decisions in post-grant proceedings bolster the validity of the '849 patent, by alleging that the patent has been battle-tested. . . . Yet, "[f]ailure to institute an IPR has little or no probative value, and, to the extent there is any probative value, it is greatly outweighed by the risk of jury confusion and the time it would take to put the failure to institute in an appropriate context." . . . . Zynga was not a party to these post-grant proceedings, further cutting against relevance. . . . Thus, the Court will generally exclude evidence of post-grant proceedings. Zynga may, however, assert prior art that has previously been introduced at the Patent Office. Because overlap in prior art references "provides a legally meaningful basis for the jury to weigh against an invalidity case, there is special relevance for the introduction of post-grant proceedings if Zynga introduces prior art that has previously been introduced at the Patent Office. Willis Elec. Co., Ltd. v. Polygroup Ltd., C.A. No. 15-cv-3443, 2024 WL 118443, at *9-11 (D. Minn. Jan. 9, 2024). Moreover, a jury may be confused and believe that the Patent Office did not have that prior art before it. Thus, if Zynga opens the door by introducing prior art raised before the Patent Office, IBM may respond by introducing evidence related to the post-grant proceedings.
International Business Machines Corp. v. Zynga, Inc., C.A. No. 22-590-GBW (D. Del. Aug. 29, 2024).
That's a pretty significant ruling. I've seen judges here hold that evidence of a plaintiff's victory at the Patent and Trademark Office can be introduced if the accused infringer argues that the prior art wasn't considered, but I don't recall another case holding that simply asserting the prior art is enough to open the door—especially where the accused infringer wasn't involved in the post-grant proceedings. This should be a helpful opinion for patentees going forward.
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