When Can a Patent Plaintiff Amend Infringement Contentions?

Where a plaintiff demonstrated that it could not have known of certain alleged bases for infringement prior to inspecting a defendant's source code, the court allowed the plaintiff to add certain claims to its infringement contentions.  United States Ethernet Innovations v. Acer, Inc., No. C 10-3724 CW (N.D. Cal. Oct. 11, 2013).

Intel had intervened in this action on behalf of its defendant customers in January, 2010.  The plaintiff had asserted certain claims of United States Patent Nos. 5,307,459, 5,434,872, 5,732,094, and 5,299,313.  In September, 2013, the plaintiff "moved to amend its infringement contentions to drop a total of nineteen claims and add three claims" from the various asserted patents.  The plaintiff asserted that it had only recently received relevant technical documents, while Intel argued that the plaintiff could not show it had acted diligently because it "failed to investigate its own information."

The applicable local patent rule allowed a plaintiff to amend infringement contentions "upon a showing of good cause and by order of the Court."  The party seeking to amend had the burden of establishing its diligence to make the required showing of good cause.

The court looked at claims from each of the two patents from which the plaintiff proposed to add claims.  With respect to claims from the '094 patent, the court agreed that the plaintiff had adequately alleged diligence because it explained it had only recently received certain source code.  Contrary to Intel's assertions, the plaintiff also plausibly alleged it could not have obtained needed information from Intel's user manuals.  Adding these claims would not add new infringement theories or "significantly affect claim construction," and therefore would not prejudice the defendants.

Concerning claim 15 from the '459 patent, the court agreed with Intel that the plaintiff had "probably" not been diligent in amending its infringement contentions.  Its software development manual was available to, and cited by, the plaintiff in 2010.  The plaintiff did not "not respond to Intel's charge that the feature was publicly available on Intel's website, nor explain why it failed to propose the changes earlier."  Nonetheless, the court found that adding the claim would not prejudice the defendants, and decided to use its discretion to allow the plaintiff to amend its infringement contentions to add the claim.  The court explained that "there is still sufficient time left on the pretrial clock, and . . . Claim 15 mirrors claims that have already been the subject of claim construction proceedings."