Supreme Court: Should Appeal Give Deference To Lower Courts On Claim Construction?

On October 15, the Supreme Court heard oral argument in Teva Pharmaceuticals USA Inc., et al. v. Sandoz Inc., et al., case number 13-854. At issue is the level of deference that the Court of Appeals for the Federal Circuit ("the Federal Circuit") should give to a lower court's patent claim construction. Based on questions and comments from the justices, the Supreme Court appears divided on this issue.

Case History

Sandoz sought approval to sell a multiple sclerosis drug similar to Teva's patented Copaxone®. The active ingredient of Copaxone® is "copolymer-1," which is recited in terms of "average molecular weight" in Teva's patents at issue.1 The district court was therefore required to construe the term "molecular weight." There are multiple accepted methods for calculating average molecular weight, each potentially yielding a different result. Teva argued, with the help of its technical expert, that one of skill in the art would recognize that the claimed average molecular weight is the molecular weight of the most abundant molecule in the sample. Sandoz argued that the claims were insolubly ambiguous with respect to the method used for calculating average molecular weight, and thus the claims were indefinite under 35 U.S.C. section 112, second paragraph. The district court sided with Teva's construction, and thus found that the claims at issue were not invalid as indefinite.

Disagreeing, the Federal Circuit exercised its de novo review to reverse the district court's indefiniteness holding, instead finding that the claims were invalid as insolubly ambiguous. The sole question presented on appeal to the Supreme Court was:

Whether a district court's factual finding in support of its construction of a patent claim term may be reviewed de novo, as the Federal Circuit requires (and as the panel explicitly did in this case), or only for clear error, as Rule 52(a) requires.

Rule 52(a) of the Federal Rules of Civil procedure requires that district court "[f]indings of fact...must...