The U.S. Court of Appeals for the Federal Circuit affirmed a district court’s denial of Novo Nordisk’s motion to preliminarily enjoin Sanofi-Aventis from “making, using, selling, offering to sell and/or import” Sanofi’s SoloStar product. Novo Nordisk A/S v. Sanofi-Aventis U.S. LLC, Sanofi-Aventis Deutschland GmbH and Sanofi-Aventis, Case No. 07-3206 (Fed. Cir., July 30, 2008) (Prost, J.).

Novo Nordisk sued Sanofi-Aventis alleging that Sanofi-Aventis, through its sale of its SoloStar insulin delivery device, infringed one or more claims of its patent directed to an insulin injection pen requiring less force to inject the insulin medication. Novo Nordisk moved to preliminarily enjoin Sanofi-Aventis and Sanofi France from making, using, selling, offering to sell and/or importing SoloStar.

The district court denied Novo Nordisk’s motion for preliminary injunction because Novo Nordisk failed to show a reasonable likelihood of success on the merits. Specifically, the district court concluded that Novo Nordisk had not shown that Sanofi-Aventis’ asserted defense—that the Sanofi SoloStar product did not infringe the ’278 patent because it lacks a direct gearing and a non-rotatable piston rod—lacks substantial merit. In support of its decision, the district court reasoned that Sanofi-Aventis raised substantial questions concerning the specification and whether the Novo Nordisk invention required direct gearing and a non-rotatable piston rod as part of every embodiment. Novo Nordisk appealed.

The Federal Circuit held that the district court did not abuse its discretion by finding that substantial questions precluded a finding that Novo Nordisk has a likelihood of success on the merits. According to the Court, the district court found that a question exists regarding whether “the very character of the invention requires a direct gearing and a non-rotatable piston rod.” Novo Nordisk argued the claims do not explicitly include these elements, while Sanofi-Aventis countered that the specification is directed to an invention centering on the gear box and non-rotatable piston rod. It held that the invention could not function without these elements. Novo Nordisk argued that the district court erred in its interpretation of the claims and required elements. The Court, however, read the district court’s opinion as addressing whether Sanofi-Aventis raised substantial questions such that the preliminary injunction failed on its merits. The Court noted “[a]t the preliminary injunction stage, however, it is irrelevant whether this case presents greater issues of claim construction or validity—the existence of one or both of these issues is sufficient to justify the district court’s decision to deny a preliminary injunction.”