Practice Areas

Print PDF

Isn’t it obvious? Presumption of obviousness knocks out patent

August / September 2022 IP Newsletter

Patents that specify ranges ­— for example, a range of concentrations in a topical composition — can run into a presumption of obviousness that results in their inventions being deemed unpatentable. A pharmaceutical company ran into just that problem when the ranges cited in its patent for a skin treatment overlapped with those in some so-called “prior art.”

Skin in the game

The case involved a patent for methods of treating acne or rosacea with a topical composition. The patent’s formulations for the composition contain certain concentrations or concentration ranges of dapsone, as well as a type of thickening or gelling agent known as A/SA. The patent also includes a “negative limitation” stating that the composition doesn’t include adapalene.

A rival pharmaceutical company filed a petition for inter partes review (IPR) with the U.S. Patent Trial and Appeal Board (PTAB). Under IPR, the board can reconsider and cancel an already-issued patent based on certain types of prior art. Prior art includes printed publications showing that the invention was anticipated or obvious.

The PTAB held that the patent would have been obvious in light of three pieces of prior art: two earlier international patent applications for topical compositions (referred to as Garrett and Nadau-Fourcade, for their respective inventors) and a journal article. All three disclosed thickeners within the ranges claimed in the patent.

The PTAB found that the combination of Garrett and Nadau-Fourcade “teach” or suggest every claim limitation at issue in this case. It further found that a person of ordinary skill in the relevant field would have been motivated to incorporate the A/SA gelling agents used in Nadau-Fourcade into Garrett’s formulations, which had called for a type of thickener known as carbomers. The court reached the same conclusion regarding the combination of the journal article, which used A/SA agents, and Garrett.

The board ultimately concluded that several of the patent claims were unpatentable. The patentee turned to the U.S. Court of Appeals for the Federal Circuit for relief.

A topical application

On appeal, the patentee contended that the PTAB shouldn’t have applied a presumption of obviousness. The presumption arises when the ranges of a variable in a patent overlap the ranges cited (or “disclosed”) in prior art.

But the Federal Circuit found it wasn’t improper to apply the presumption. In the absence of evidence that there’s something special about the range in a challenged patent, the court said, an overlap with prior art suffices to show that the claimed range was obvious. And, absent a reason to conclude otherwise, the PTAB was justified in concluding that the range disclosed in Garrett disclosed the range in the challenged patent. That, the appellate court said, was enough to create a presumption of obviousness as to the claimed amounts in the patent — a presumption the patentee failed to overcome.

Moreover, the Federal Circuit found that the outcome would be the same even if the presumption didn’t apply. The case didn’t turn on overlapping ranges. Rather, it was a simply a case of substituting one known gelling agent for another. As the board found, a skilled artisan would have been motivated to make the substitution.

One more fight to pick

The patentee also argued that the PTAB failed to account for the negative adapalene claim limitation. Garrett didn’t indicate that any of its formulations included adapalene, but the patentee argued that wasn’t enough to disclose or teach the negative limitation in its patent.

The court disagreed. It reiterated that prior art doesn’t need to state the absence of a feature to disclose a negative limitation. It was reasonable for the board to find that a skilled artisan would recognize that Garrett discloses a complete formulation that excludes the possibility of an additional active ingredient, such as adapalene.

Cleared up

The PTAB and Federal Circuit’s holdings provide valuable guidance on the applicability of the presumption of obviousness and what’s required to disclose a negative limitation. They also reinforce the importance of carefully reviewing prior art and drafting patents accordingly.

Sidebar: Obviousness doesn’t require “absolute predictability”

The court in Almirall (see main article) also considered whether a skilled artisan in the relevant field would have had a reasonable expectation of success in substituting a thickener from an earlier patent application for a topical composition (the A/SA gelling agents) for the thickener used in the formulations of another application (carbomers). A finding of obviousness requires, among other things, that a skilled artisan would have had a reasonable expectation of success in combining or modifying prior art.

The U.S. Court of Appeals for the Federal Circuit explained that the requisite reasonable expectation of success can exist without “absolute predictability of success.” It cited expert testimony that a skilled artisan would have understood that the substitution would have been routine and predictable because the A/SA agents were known for use in topical compositions with water-insoluble drugs.

The two kinds of thickeners were recognized as interchangeable gelling agents for topical formulations with dapsone that could be used in the same concentration range. This fact supported the reasonable success determination.

Link to the newsletter here