The Federal Circuit recently held that it had no jurisdiction to review a district court's claim construction ruling where the patentee withdrew its infringement claims after claim construction, without ever obtaining a final judgment of noninfringement as to those claims. See Sandisk Corp. v. Kingston Tech. Co., 2011-1346 (Fed. Cir. Oct. 9, 2012).
Sandisk filed suit against Kingston alleging infringement of five different patents. After the district court issued its claim construction ruling, Sandisk withdrew its infringement claims with respect to two of the patents-in-suit and several asserted claims of a third patent-in-suit. On the parties' subsequent cross motions for summary judgment, the district court found infringement as a matter of law as to several claims of the asserted '424 patent. The district court found no infringement as a matter of law as to the other remaining claims. In its summary judgment order, the court acknowledged that Sandisk had withdrawn several of its asserted infringement claims, but did not enter any judgment with respect to those withdrawn claims.
The parties then entered into a Stipulation and Order whereby Sandisk dismissed without prejudice its infringement claims involving the '424 patent, and Kingston dismissed without prejudice its related invalidity and unenforceability counterclaims. The parties agreed that the "Stipulation shall not in any way prejudice any party's right to appeal this matter in whole or in part, including, but not limited to, an appeal of the Court's September 22, 2010 Claim Construction Order." Pursuant to the Stipulation and Order, the court entered Final Judgment of noninfringement. The court's Final Judgment did not address the withdrawn claims.
Sandisk then attempted to appeal the district court's claim construction rulings, both for terms in the '424 patent and for terms that appeared only in the withdrawn claims. The Federal Circuit found that it did not have jurisdiction over the district court's claim construction ruling for terms that appeared only in the withdrawn claims. Because there was no Final Judgment with respect to those claims, the claim construction for those terms did not present a current infringement controversy for the Court's review. The Court noted that "where, as here, a party's claim construction arguments do not affect the final judgment entered by the court, they are not reviewable." The Court was not persuaded by the patentee's argument that the Stipulation evinced the patentee's intention to pursue its claim construction arguments on appeal. Instead, the Court observed that the parties' agreement could not cure the jurisdictional defect of having no final judgment from which to appeal. Even if both parties concede appellate jurisdiction, their agreement cannot create a right to appeal where none exists.
Sandisk demonstrates that even a pure issue of law, such as claim construction, may not be appealable if the proper steps are not followed. Sandisk was apparently trying to streamline the litigation by withdrawing claims from the case once it received an unfavorable claim construction ruling. But by not taking the step of obtaining a stipulated final judgment of noninfringement, it ultimately lost its right to challenge the unfavorable claim construction ruling it disagreed with.