Akorn, Inc. v. Senju Pharmaceutical Co., Ltd.

IPR2015-01205 (U.S. Pat. No. 6,114,319)
November 22, 2016

Brief Summary: PTAB final decision found all claims of US 6,114,319 relating to Alcon’s ophthalmic emulsion Durezol® unpatentable for obviousness.

Summary: This IPR relates to previously reexamined US 6,114,319 encompassing “difluprednate emulsion[s] in the form of an eye drop, a nasal drop or an ear drop”. The ‘319 patent is the only patent listed on the FDA Orange Book for Alcon’s ophthalmic emulsion Durezol® (0.5% difluprednate; Appln. No. N022212). Pending litigation (C.A. No. 2:15-cv-00285-MCA-JBC (D.N.J.) was stayed on Jan. 8, 2016 pending this IPR decision. The ‘319 patent includes two independent claims, 1 and 18, that require difluprednate, an oil selected from a Markush group (castor oil in claim 18), water, and an emulsifier (polyoxyethylene (20) sorbitan monooleate in claim 18). Akorn challenged ‘319 claims 1-4, 6-10, 12-14 and 18 as obvious over two prior art references. The US ‘848 patent was alleged to show that difluprednate was known as an anti-inflammatory for the eye. A PCT application (“Ding”)) was alleged to show that it was known to formulate steroids in emulsions using, e.g., polysorbate 80, aka polyoxyethylene (20) sorbitan monooleate. The PTAB agreed with each of these characterizations. Senju argued using an emulsion would have been “very challenging and unpredictable” and that the challenge is based on hindsight. The PTAB was “persuaded that those of ordinary skill in the art would have at least considered formulating difluprednate as an emulsion to have been obvious.” Senju also argued that “Ding only targets the lacrimal gland of the eye, which is external to the eyball, not the interior of the eyeball, where the ‘319 patent indicates difluprednate is active.” Despite expert testimony to this point, the PTAB was not persuaded “that those of skill in the art would not have considered Ding because it teaches emulsions that target areas exterior to the eyeball” and that those of skill in the art would have been motivated to combine it with the ‘848 patent because it “indicates difluprednate is useful for ailments such as types of conjunctivitis [pink eye] and blepharitis marginalis” (which, it is noted here, are also conditions on the exterior of the eye). Senju’s arguments regarding reduced particle size were also not accepted. And its arguments regarding the “countless experiments” that may have been required were rejected since “the challenged claims are not drawn to methods of treating an ailment with an emulsion of difluprednate.” Evidence unexpected results was also found to be unpersuasive because, e.g., the evidence presented did not convince the PTAB that “the emulsion formulation of the drug”, and not the known drug itself, “was responsible” or that the “improved delivery” was unexpected. The PTAB was also unpersuaded by arguments of a long-felt need (e.g., “the mere passage of time without the claimed invention is not evidence of nonobviousness”, Iron Grip, FC 2004), industry acclaim (“the record does not indicate sufficiently that the praise was based on the use of difluprednate in an emulsion, as claimed, rather than the use of difluprednate itself”), or copying. The dependent claims were separately addressed and also found to be unpatentable.

This entry was posted in Inter Parties Review (IPR), IPR, Obviousness. Bookmark the permalink.

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