A Little history of the case:

Sandoz -Appellants submitted Abbreviated New Drug Applications (ANDAs) to the Food and Drug Administration (FDA) seeking approval to market generic versions of Copaxone®. Teva, which markets this drug sued Appellants for patent infringement under 35 U.S.C. § 271(e)(2)(A).

Patent involved is US 5800808 A claiming

Copolymer “having a molecular weight of about 5 to 9 kilo daltons.There are three different measures of molecular weight relevant to this appeal: peak average molecular weight (Mp), number average molecular weight (Mn), and weight average molecular weight (Mw).

A patent is indefinite “if its claims, read in light of the specification, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.”

Each measure calculated in a different manner. The claim does not specify which measure to use and in a typical polymer sample, Mp, Mn, and Mw have different values.

Earlier district court rejected appellant’s argument that molecular weight is indefinite.The district court found credible Dr. Grant’s testimony that Mp is the only type of average molecular weight that can be directly obtained from a chromatogram and calibration curve obtained by the analytical method described in Example 1.We see no clear error in the district court’s decision to credit Dr. Grant’s testimony.

Prosecution History

A patent is indefinite “if its claims, read in light of the specification, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.”

Each measure is calculated in a different manner. The claim does not specify which measure to use and in a typical polymer sample, Mp, Mn, and Mw have different values.

Earlier district court rejected appellant’s argument that molecular weight is indefinite.The district court found credible Dr. Grant’s testimony that Mp is the only type of average molecular weight that can be directly obtained from a chromatogram and calibration curve obtained by the analytical method described in Example 1.We see no clear error in the district court’s decision to credit Dr. Grant’s testimony.