Addressing the validity of patent claims reciting concentration ranges, the U.S. Court of Appeals for the Federal Circuit reversed in part a district court decision that patent claims were not obvious.  Alcon Research, Ltd. v. Apotex Inc., Case No. 11-1455 (Fed. Cir., Aug. 8, 2012) (Moore, J.).

The patent at-issue was directed to the use of a composition to treat allergies that includes olopatadine, the active ingredient in Alcon’s anti-allergy eye drop Patanol™.  The first independent claim of the asserted patent covered a treatment of “allergic eye diseases in humans comprising stabilizing conjunctival mast cells by topically administering to the eye a composition comprising a therapeutically effective amount of [olopatadine].”  That independent claim did not specify what a “therapeutically effective amount” of olopatadine was, but dependent claims recited a range from about 0.001 percent to about 5 percent, including two dependent claims that specifically recited 0.1 percent.  The accused product Patanol contained 0.1 percent olopatadine.

At the time of invention, it was known that olopatadine was an effective antihistamine, and methods of treating allergies using olopatadine were already patented.  A prior art reference to Kamei disclosed testing of ophthalmic formulations of 0.0001-0.01 percent olopatadine in guinea pig eyes at concentrations that overlap with the range recited in most of the asserted patent claims. Nevertheless, the district court held the patent was non-obvious and that Apotex infringed.

On appeal, to avoid the Kamei reference, Alcon argued that olopatadine concentrations at the low end of the claimed 0.001-0.5 percent range do not stabilize mast cells to a clinically relevant extent, and should be excluded from the scope of the independent claim based on the “therapeutically effective amount” limitation.  The Federal Circuit rejected Alcon’s argument that the claims “would be operative, just at a narrower concentration than the claimed range,” stating “courts do not rewrite the claims to narrow them for the patentee to cover only the valid portions” of the range.  Thus, stated the Court, if a concentration within the recited range is “admittedly not enabled, then the entire claim is invalid.”  The Federal Circuit stated further that, “if the prior art discloses a portion of the claimed range, the entire claim is invalid.”  Moreover, because the olopatadine concentrations disclosed in the Kamei reference overlapped the claimed concentrations, the “therapeutically effective” and “stabilizing conjunctival mast cells” claim limitation were met by Kamei.

The Federal Circuit found that several claims were invalid in view of the Kamei reference.  However, because the olopatadine concentrations tested in Kamei were substantially lower than the 0.1 percent recited in two of the dependent claims, and in view of evidence regarding Patanol’s commercial success, the Federal Circuit affirmed the district court’s finding that the two dependent claims were not obvious.