Bottom line: Characterizing the invention as “may be” having a particular feature is generally effective in maintaining the breadth of a claim. By being noncommittal, the courts are less likely to import those particular features as requirements into the claims of the patent. Patent claims can be narrowed based on statements made in the specification and the prosecution history of the patent. In Cadence Pharmaceutical v. Exela Pharmsci Inc. (Fed. Cir. 2015), the claims of the patent at issue included a “buffering agent” limitation. Although the patent’s specification included potentially narrowing statements in relation to the concentration of the buffering agent as being between 0.1 and 10 mg/ml, the Court did not construe the “buffering agent” limitation as being limited to those specific concentration levels because the patent’s specification stated that the concentration of the buffer “may be” between 0.1 and 10mg/ml.
The scope of patent protection is defined by the claims. Each limitation (i.e., word) in each claim, during litigation, is given a meaning. Normally, each word is given its ordinary meaning unless the inventor acts as his or her own lexicographer but to do so , the inventor must express a clear intent in the patent specification or the prosecution history.
During the trial court proceedings of the Cadence case, the court construed the term “buffering agent” broadly to mean “an agent that helps the formulation resist change in pH.” The defendant proffered a more narrow constructions of the “buffering agent” limitation to further require that the buffering agent have a sufficient concentration to prevent a material change in pH. The defendant wanted the claim to be narrowed so that the buffering agent cannot merely have a concentration that helps resist change at any level but must materially resist such change in pH.
The Federal Circuit held that even though all of the embodiments stated in the patent recited a specific concentration for the buffering agent, importing such level of concentration would be improperly importing features described in the specification as limitations in the claims. Simply put, the patent specification did not express a clear intent to redefine the term “buffering agent” to include the specific concentration levels.
In general, the patent specification should be drafted to broadly describe the invention and also include specifics regarding various aspects of the invention. The specifics provide backup arguments for patentability downstream during prosecution of the patent application before the USPTO. Although the specifics should be included in the patent application, the potential for those specifics to limit the claim is possible as illustrated by the Cadence case. To mitigate this possibility, as a patent drafting tip, describing the invention or aspects thereof in terms of what it “may be” and not what it “is” may reduce the possibility that the specifics would limit the patent’s claims.
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