University of California v. Dakocytomation California (Dako) (Fed. Cir. 2008)
Plaintiffs UC and Abbott are the owner and licensee of a set of patents covering methods of identifying chromosomal abnormalities. On appeal, the parties question whether the lower court improperly denied preliminary relief joined with an interlocutory appeal of summary judgment of non-infringement of some claims.
As in the recent Chamberlain Group decision, the appeal of preliminary relief offered a method for the parties to obtain an interlocutory judgment on claim construction.
District Court Obviousness Trouble: On two separate occasions, the district court denied preliminary relief to the patent holder based on the likely invalidity of the asserted patents. First, the district court held that the patent was likely invalid based because the parent application was invalidating prior art. The court withdrew that analysis after realizing that the asserted patent claimed priority to the filing date of the parent. Next, the district court found the patent likely invalid for obviousness-type double patenting. That reasoning was also withdrawn by the district court after realizing that the patentee’s terminal disclaimer cured the double patenting defect.
Nonetheless, the lower court’s decision in favor of the defendant stuck because the CAFC found that the prosecution history warranted a construction of the claims that was narrow enough to allow Dako to avoid infringement.
Doctrine of Equivalents: In a decision to be contemplated further, the CAFC also decided that a narrowing amendment made during prosecution does not preclude application of the doctrine of equivalents because “the narrowing amendment was only tangential to the accused  equivalent.”
Judge Prost dissented from the DOE holding and argued that the amendment was absolutely related to the accused equivalent.