Positive Times for Negative Limitations: Part 2

Just this month, the Federal Circuit again took up the issue of a negative claim limitation.  But, this time, it was from a different perspective, i.e., whether a prior art reference met a negative claim limitation, even though the prior art disclosure made no mention of the excluded feature.  Amneal Pharmaceuticals LLC v. Hirshfeld, No. 20-23311-1070, March 14, 2022 (Fed. Cir. 2022)

Amneal appealed from a final written decision of the PTAB (IPR 2019-0207 and IPR 2019-01095) that found claims of US 9,517,219 to be obvious in view of Garrett (WO 2009/061298) and Nadau-Fourcade (WO 2010/029958).  The claims were directed to a method of dermatological conditions using a composition containing dapsone.  The claims further included a negative limitation, i.e., “wherein the topical pharmaceutical composition does not comprise adapalene.”  Both dapsone and adapalene are active agents known for treating dermatological conditions.

The primary reference Garrett taught a dermatological composition containing dapsone.  The disclosure made no mention of adapalene, nor the exclusion thereof.  The Board, however, found that Garrett taught this negative limitation because Garrett disclosed “complete” formulations that did not contain adapalene.  The Federal Circuit agreed.

The court did not explicitly describe what is meant be a “complete” formulation.  But, a review of the Garrett disclosure may shed some light.  Garrett described a genus of formulations containing amounts of carbomer, water, ethoxydiglycol, methyl-paraben, dapsone and sodium hydroxide solution, wherein the amount for each component is described by a range, e.g.,” about 5% to 10% dapsone.”   Garrett further described more specific embodiments which listed these same components in specified amounts, albeit with the qualifier “about,” e.g., “about 5% dapsone.”  In at least one of these narrower embodiments, the amounts added up to 100%.  Finally, Garret described a method of preparing a formulation using specific amounts of these components without the qualifying term “about.”  The amounts added up to 100%.

The court held that “it was reasonable for the Board to find that, in the context of Garrett, a skilled artisan would recognize that the reference discloses a complete formulation—excluding the possibility of an additional active ingredient.”  The court also cited their recent decision in Novartis Pharmaceuticals Corp. v. Accord Healthcare, Inc., No. 21-1070, Jan 03, 2022 (Fed. Cir. 2022) for the principle that for negative limitations the disclosure must be read from the perspective of one skilled in the art.

Since the inquiry here concerns a prior art disclosure (and, particularly, in an obviousness context), the burden of meeting the negative limitation seems easier to satisfy.  If a skilled artisan is asked, in light of the described “complete” formulation, does Garrett describe a formulation which does not comprise adapalene, the answer seems a straightforward yes.  As the court stated, “It is undisputed that Garrett discloses dapsone formulations that lack adapalene.”  The inquiry is a bit different if the skilled artisan is asked whether Garrett has written description support for a claim that excludes adapalene, but does not exclude other unnamed dermatologically active compounds or unnamed non-active compounds.

If you have any questions regarding negative claim limitations or any of the issues discussed above, please contact Brion Heaney at Heaney@MWZB.com


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