Today, the Supreme Court in SCA Hygiene Prods. v. First Quality Baby Prods. (2017) held that the defense of laches cannot be invoked in patent cases to prevent legal damages within the 6-year statutory limitation set forth by 35 U.S.C. 286. In the overwhelming majority opinion authored by Justice Alito, the Court reiterated that laches is a judicial doctrine designed as an equitable relief, where there is no statute of limitations enumerated by law, or in other words, that laches is "a gap-filling doctrine, and where there is a statute of limitations, there is no gap to fill", but rather, "applying laches within a limitations period specified by Congress would give judges a 'legislation overriding' role that is beyond the Judiciary's power." For the full opinion -- https://www.supremecourt.gov/opinions/16pdf/15-927_6j37.pdf
The equitable defense of laches can apply to claims of patent infringement damages suits, even when they are filed within the six year statutory period as defined by 35 U.S.C. §286, ruled the en banc Federal Circuit in SCA Hygiene Products Aktiebolag v. First Quality Baby Products, LLC., Fed Cir., No. 2013-1564 (Sept. 18 2015). In this narrow 6-5 decision, the court sitting en banc affirmed its earlier summary judgment, which dismissed SCA's patent infringement suit for laches, from September of last year.