A recent case is a reminder of a claim construction lesson that all litigants should keep in mind. Last Friday, Novartis AG’s Alcon Inc. subsidiary asked the Supreme Court to reverse a Federal Circuit decision in favor of Apotex relating to Alcon’s Patanol (olopatadine) ophthalmic formulation. The case is interesting because of its unusual procedural aspects, namely, how Alcon’s broad claim construction position came back to haunt it on appeal, even when the claim construction itself was not appealed.

Claim 1 of the patent in suit recited a method of treating human eye allergies “comprising stabilizing conjunctival mast cells” by administering “a therapeutically effective amount” of the active drug. At Alcon’s urging, the district court construed the term “stabilizing conjunctival mast cells” to limit the claims of the drug that stabilize the mast cells “to an extent clinically relevant” in the treatment of allergic eye disease. Various dependent claims contained explicit amounts of the olopatadine, thus implying that those amounts were amounts sufficient to stabilize human mast cells to a clinically relevant extent. Alcon, in hopes of distinguishing various prior art, argued at trial that some olopatadine concentrations covered by the dependent claims did not stabilize human conjunctival mast cells to a clinically relevant extent. The district court agreed, ruling that most of the patent claims were infringed and not invalid based on the prior art.

Apotex appealed the finding of non-obviousness, but not the claim construction. While the Federal Circuit acknowledged that the claim construction had not been appealed, the appellate court nevertheless conducted an analysis of the scope of claim 1, based on the express limits of the amounts of active drug set forth in the dependent claims. Alcon argued on appeal that, to the extent that the dependent claims covered a broader range than that needed to stabilize the mast cells, the inoperative portion of the range would not be covered by claim 1’s construction that the mast cells must be stabilized to a clinically relevant extent. The Federal Circuit disagreed, reasoning that the independent claim, being at least as broad as the dependent claims, must necessarily include those amounts of the active drug. The Court in effect said that the claims may have included portions of the ranges that were inoperative was Alcon’s problem. The Federal Circuit then went on to find the claims invalid in view of the prior art.

Alcon’s petition to the Supreme Court is based on the premise that a dependent claim cannot be broader than the claim from which it depends. While that proposition, in the abstract, is correct, the facts of this case suggest that the Federal Circuit’s interpretation of the scope of claim 1 was warranted because of Alcon’s attempt to distinguish the prior art. As such, it is unlikely that the Supreme Court will grant the petition.

The takeaway of this case is simple. Be careful for the claim construction you seek, for if it is so broad as to ensnare the prior art, you may be making the case of infringement easier but invalidating your patent in the meantime.