Hor v. Chu

The time period for asserting the defense of laches against an inventorship claim is measured from the date the patent was issued, not from the date the patent application was filed.

Opinion (Prost): In 2008, Pei–Herng Hor and Ruling Meng sued Ching–Wu Chu seeking to correct their omission as inventors from two patents. The compositions claimed in the patents were conceived between 1986 and 1987. The patent applications were filed in 1987 and 1989, and the patents were issued in 2006 and 2010, naming Chu as the sole inventor. The district court granted Chu’s motion for summary judgment, finding the claims were barred by laches because Hor and Meng knew or should have known of the claims by the early 1990s, before the patents had issued. Hor and Meng appealed. For § 256 inventorship claims, a delay of 6 years after the claim accrues, raises a rebuttable presumption that the claim is barred by laches. That claim, however, does not accrue until the patent is issued. Because Hor initially filed suit in 2008, and added the additional patent claim in 2010, the delay between the accrual of the claim (issuance of the patent) and filing suit was less than 6 years, and the claims, therefore, were not barred. Ruling in the alternative, the district court, sua sponte, found that Hor and Meng’s claims were barred by equitable estoppel. Estoppel “is an affirmative defense that must be pled,” otherwise the defense may be considered waived. Because Chu did not assert equitable estoppel as an affirmative defense, the Federal Circuit held that the district court erred in granting summary judgment on that basis. Summary judgment was REVERSED.