Invalidity Is Not a Defense to Infringement but a Defense to Liability

The Federal Circuit recently refused to apply collateral estoppel to claims of a patent asserted in district court litigation based on a Patent Trial and Appeal Board (PTAB) decision finding similar claims from the same patent unpatentable because the PTAB applied a lower burden of proof than what is required to invalidate claims in district court.

The Central District of California denied a defendant’s motion to dismiss or transfer plaintiff’s first-filed declaratory judgment action based on defendant’s later-filed patent infringement suit in Wisconsin.  Though suit was seemingly imminent when defendant advised plaintiff it might be infringing defendant’s patents, plaintiff responded by requesting a licensing agreement in lieu of litigation. The court found that plaintiff’s action was not anticipatory forum-shopping litigation because plaintiff only filed suit after defendant neglected to respond to its licensing offer.

The District of Delaware recently denied in part a motion to compel production of documents and testimony between a patentee and potential investors, valuation firms and an international bank based on the common interest exception. In so doing, the court reaffirmed that disclosure of privileged information to third parties will generally waive privilege unless it can be shown that the parties’ interests are identical and the communications are legal, not solely commercial.

The Federal Circuit affirmed a Patent Trial and Appeal Board (PTAB) final written decision holding that the prior art exception of AIA Section 102(b)(2)(B) does not apply to a prior sale by an inventor when the sale is conducted in private. According to the Federal Circuit, a sale must disclose the relevant aspects of the invention to the public to qualify for the prior art exception of Section 102(b)(2)(B).

Under the Lanham Act, a plaintiff who prevails on a trademark infringement claim may be entitled to recover the “defendant’s profits” as damages. The Supreme Court in Dewberry Group, Inc. v. Dewberry Engineers Inc. unanimously construed “defendant’s profits” in 35 USC § 1117(a) to mean that only the named defendant’s profits can be awarded, not the profits of other related corporate entities. The Court, however, left open the possibility that other language in § 1117(a) may allow for damages linked to the profits of related entities, if properly raised and supported.

In a series of rulings on a motion in limine, the District of Delaware recently distinguished between what qualifies as being incorporated by reference and what does not for the purposes of an anticipation defense. In short, a parenthetical citation was held to be insufficient, while three passages discussing a cited reference met the test.

On February 28, 2025, the USPTO announced that it was rescinding former Director Vidal’s 2022 memorandum on discretionary denials by the Patent Trial and Appeal Board. The 2022 memorandum effectively narrowed the application of discretionary denials in cases with parallel district court litigation by specifying instances where discretionary denial could not be issued. With the withdrawal of the memorandum, individual PTAB panels will regain flexibility in weighing discretionary denials. While the long-term effect of that increased flexibility is not yet known, the immediate effect is likely to be a shift towards the discretionary analysis applied by PTAB panels before the issuance of the memorandum.

A District of Delaware judge recently granted a defendant’s motion to include a patent prosecution bar in its proposed protective order after determining that litigation counsel’s ability to practice before the Patent Office—without ever having represented the plaintiffs at the Patent Office in the past—weighed heavily in favor of the bar.