Summary: A plaintiff need not prove its case of patent infringement at the pleading stage. To the extent a defendant disputes the pleaded allegations or claim scope, these inquiries are not suitable for resolution on a motion to dismiss.

Nalco’s asserted patent was directed to a method of removing elemental mercury from the flue gas created by combustion in coal-fired power plants. Nalco alleged that the defendants’ combustion process operates in the same manner as the claimed method. The district court granted the defendants’ motions to dismiss under Rule 12(b)(6) of Nalco’s five successive complaints for factual deficiencies in pleading various infringement theories. Nalco appealed after the district court’s dismissal of its Fourth Amended Complaint.

The Federal Circuit reversed and reinstated all the claims, finding that Nalco has adequately pled its infringement theories under the Twombly and Iqbal pleading standard. For the direct infringement claims, the Federal Circuit found that Nalco had plausibly alleged its direct infringement theories and that the district court had inappropriately resolved disputes on a Rule 12(b)(6) motion without the benefit of claim construction, such as of the claim term “flue gas.” The Federal Circuit also reversed the district court’s dismissals of the indirect infringement and willful infringement claims, which were solely based on the dismissal of the underlying direct infringement claim. The Federal Circuit held that factual disputes related to those claims should not be resolved at the Rule 12(b)(6) stage.