Inherent limitations of the prior art must be commensurate in scope with the actual limitations claimed in order to establish anticipation or obviousness. Here, for example, an inherent food effect advantage of nanosized formulations of a particular drug was found to be insufficient to establish that an otherwise obvious reduction in particle size would naturally result in the more specifically claimed “no substantial difference” in the food effect. “[T]he limitation at issue necessarily must be present, or the natural result of the combination of elements explicitly disclosed by the prior art.” This would be a good case to consult and cite in response to a general assertion of inherency with respect to a more specifically claimed limitation.
Background / Facts: The patent being asserted here in response to a generic drug ANDA submission is directed to use of nanosized formulations of the otherwise well-known drug megestrol acetate (“megestrol”) to “increas[e] the body mass in a human patient suffering from anorexia, cachexia, or loss of body mass.” An advantage of nanosized formulations discovered by the inventors is a greatly reduced “food effect,” such that the drug can be taken without accompanying meals. In this regard, claim 1, for example, requires “no substantial difference in [max blood plasma concentrations] Cmax” between fed and fasted states. Even though it acknowledged that the prior art did not explicitly disclose the food effect differences as claimed, the district court concluded that “[t]he claimed pharmacokinetic parameters with respect to a food effect … are inherent properties of the obvious nanoparticulate formulation.”
Issue(s): Whether the specific food effect limitation of “no substantial difference” is inherently disclosed in the prior art.
Holding(s): No. “The district court’s broad diktats regarding the effect of particle size on bioavailability and food effect are not commensurate with the actual limitations at issue. While it may be true that a reduction in particle size naturally results in some improvement in the food effect, the district court failed to conclude that the reduction in particle size naturally results in ‘no substantial difference’ in the food effect.”