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CAFC Updates


By August 11, 2022March 7th, 2024No Comments

This case was remanded by the Supreme Court to the CAFC to consider whether assignor estoppel should preclude Minerva from challenging the validity of claim 1 of Hologic’s U.S. Patent No. 9,095,348 (relating to a moisture transport system for contact electrocoagulation). The CAFC previously held that the district court did not abuse its discretion in applying the doctrine of assignor estoppel, but the Supreme Court held that assignor estoppel applies only when an inventor says one thing (explicitly or implicitly) in assigning a patent and the opposite in litigating against the patent’s owner. Thus, the questions before the CAFC are: (1) whether Minerva warranted the validity of certain cancelled claims at the time of assignment; and (2) whether that cancelled claim is materially broader than claim 1 of the ’348 patent. The CAFC finds that cancelation of a claim in response to a restriction requirement says nothing, implicitly or explicitly, about the patentability of the claim, and further that the cancelled claim can be assigned. However, the CAFC finds that Minerva represented that the subject matter of the cancelled, assigned claim was not invalid based on 1) an oath stating the inventor’s implicit good-faith belief that the claims in the application are patentable and would result in a valid patent, 2) a successful defense of the claim from an anticipation rejection before its cancelation, and 3) a subsequent assignment, in which the assignor warranted that it had no present knowledge from which it could reasonably conclude that the assigned IP rights were invalid or unenforceable. After considering the intrinsic record as a whole, the CAFC further holds that claim 1 of the ’348 patent is not materially broader than the cancelled claim. The CAFC therefore holds that Minerva is estopped from challenging the validity of the ’348 patent claims based on the doctrine of assignor estoppel and affirms the district court’s summary judgment that claim 1 of the ’348 patent is not invalid.  

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