Earlier this week, the Federal Circuit relied on the obscure “Kessler Doctrine” to prevent a patentee from asserting its patent in the case of Brain Life, LLC v. Eleckta Inc., 2014 U.S. App. LEXIS 5390 (Fed. Cir. March 24, 2014). The little-used Kessler Doctrine traces its roots back to the U.S. Supreme Court case of Kessler v. Eldred, where the Court prohibited a patentee from suing a defendant’s customers for patent infringement in connection with lighters identical to those the defendant had shown to be non-infringing in prior litigation. Kessler v. Eldred, 205 U.S. 285 (1907).
This past week the Federal Circuit applied the Kessler Doctrine to “fill the gap” between claim preclusion and issue preclusion. Brain Life, LLC, 2014 U.S. App. LEXIS 5390 at *17-*22. Claim preclusion was unavailing to the defendant in Brain Life because the allegedly infringing acts took place after judgment was entered in the first suit. Id. at *17. Issue preclusion was likewise unavailing because the claims asserted in the second litigation were not the same as had been asserted in the first litigation. Id. at *22. However, the Federal Circuit explained that the defendant was nonetheless protected from the second suit under the Kessler Doctrine because the products at issue were “essentially the same” (“no material differences”) as the products that were previously found not to infringe that same patent. Id. at * 31.
The Brain Life patentee tried to argue that the sameness of the products was irrelevant, because the claims asserted in the second suit were not “essentially the same” as the claims that were asserted in the first suit. Id. But the Federal Circuit rejected the patentee’s argument, explaining the argument is “beside the point under the Kessler Doctrine because [the] products have acquired the statute of non-infringing products as to the ‘684 patent, i.e., all the claims that were brought or could have been brought in the first suit.” Id. (emphasis in original).
In short, under the Kessler Doctrine, if your product is found not to infringe a patent in a first litigation, the patentee cannot sue you or your customers in a second litigation for making, using or selling a product that is “essentially the same” as the product found to be non-infringing in the first litigation — regardless of which claims were asserted in the first litigation.