by Dennis Crouch
Par Pharma v. TWI Pharma (Fed. Cir. 2014)
In a strong opinion, the Federal Circuit has overturned a lower court summary judgment that Par’s megestrol formulation patent claims are obvious. (U.S. Patent No. 7,101,576). The case is interesting because it further solidifies the appellate court’s stance that functional claim limitations should be given their full weight and merit even when serving as the point-of-novelty of the invention.
As with many drug-related patents, Par’s claims include limitations regarding the effect of the drug. Here, the real benefit of Par’s formulation is that it is equally effective if administered in both a “fed” and “fasted” state. During prosecution (and in response to an obviousness rejection), par added the follow food-effect limitation: “wherein after a single administration … there is no substantial difference in the Cmax of megestrol when the formulation is administered to the subject in a fed versus a fasted state.” The remainder of the claim involves a series of specific dosages and particle size limitations to be used in the drug administration.
At trial, the district found the claims obvious based upon a combination of prior art references. Notably, the prior art was not shown to teach the food-effect limitation. However, the district court determined that the wherein clause deserved no weight in the obviousness analysis because it was simply describing a result inherent to the formulation.
On appeal, the Federal Circuit has vacated that finding — noting that the district court “incorrectly applied our law on inherency in the context of obviousness.”
Inherency: The traditional approach to inherency is with reference to the prior art — even when not expressly disclosed by the prior art, a feature will be deemed inherent to the prior art if “the natural result flowing from the operation as taught would result in the performance of the questioned function.” Hansgirg v. Kemmer, 102 F.2d 212, 214 (C.C.P.A. 1939). In the obviousness-combination context, the question is whether the non-disclosed limitation is the natural result of the combination of reference. In re Oelrich, 666 F.2d 578, 581 (C.C.P.A. 1981) (“[M]ere recitation of a newly discovered function or property, inherently possessed by things in the prior art, does not distinguish a claim drawn to those things from the prior art.”). The Federal Circuit here writes “the limitation at issue necessarily must be present, or the natural result of the combination of elements explicitly disclosed by the prior art.”
Of importance, however, the “natural flow” must be proven with clear and convincing evidence and may not be established by probabilities or possibilities or expectation.
In reviewing the evidence presented in this case, the appellate panel found that the challenger had failed to present sufficient evidence of inherency. In particular, althought the evidence presented showed that the combination would improve the food-effect, there was no evidence presented that the food effect was substantially eliminated as required by the claims.
While it may be true that a reduction in particle size [as disclosed in the prior art] 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.
On remand, the district court will likely consider further evidence with regard to inherency.
The case here also ties-in with Mayo v. Prometheus. Following that decision, the claimed food-effect as a result of the particular administration would be seen as an unpatentable law of nature. The question then is whether that claimed function can serve as the point of novelty sufficient to overcome the prior art.