Intendis GMBH. v. Glenmark Pharms. Ltd.

Proposed ANDA formulation infringed the patent-in-suit under the doctrine of equivalents; defendants’ obviousness defense was also rejected.

October 14, 2015

GENERICally Speaking

Case Name: Intendis GMBH. v. Glenmark Pharms. Ltd., 13-421 (SLR), 2015 U.S. Dist. LEXIS 97403 (D. Del. July 27, 2015) (Robinson, J.) 

Drug Product and Patent(s)-in-Suit: Finacea® Gel, 15% (azelaic acid gel); U.S. Pat. No. 6,534,070 ("the '070 patent")

Nature of the Case and Issue(s) Presented: Plaintiffs hold an exclusive license to the '070 patent, which covers Finacea, an azelaic acid gel formulation used to treat mild to moderate rosacea. Plaintiff Bayer holds the approved NDA for Finacea and is also its exclusive distributor. On July 27, 2012, defendants filed an ANDA for a generic azelaic acid gel, 15% formulation. In response, Plaintiffs sued for patent infringement.

The parties' dispute centered around two main issues. First, was defendants' substitution of isopropyl myristate the equivalent of a "lecithin" for the purposes of infringement? And second, was the '070 patent invalid as obvious in light of the prior art? After a bench trial, the court determined that the '070 patent was valid and infringed.

Why Plaintiffs Prevailed: The court construed one claim term, "hydrogel," in its analysis. The issue was whether a "hydrogel" could include an insoluble liquid.  The court concluded that it could. The specification of the patent referred to a gel containing vesicles or nanoemulsion—insoluble liquids. This disclosure was supported by one of the dependent claims, which claimed a vesicle-free gel. Accordingly, based on principles of claim differentiation, the independent claim asserted must have contained vesicles. Further, an example from the prosecution history indicated that a gel containing vesicles would form when lecithin concentration in the gel ranged from 1-5%, as called for in the patent. Thus, a "hydrogel" also could contain insoluble liquids.

Next, the court determined that defendants’ formulation, using isopropyl myristate, contained the equivalent of a lecithin by applying the function-way-result test. The court found that lecithin, in combination with triglycerides, functioned as a "penetration enhancer," as did isopropyl myristate. And although the plaintiffs originally described the function of lecithin and triglycerides as a "moisturizer" or "emollient," such descriptions did not exclude other functions. Finally, throughout their ANDA filings, defendants stated that lecithin, triglycerides, and isopropyl myristate functioned as penetration enhancers. Thus, the “function” portion of the test was satisfied.

The compounds also functioned in the same way. Although the '070 patent did not specify a particular mechanism for penetration enhancement, the court determined, based on the expert evidence presented, that all of the excipients at issue worked using substantially similar mechanisms. This was sufficient to satisfy the “way” part of the test; an exact match was not necessary.  Since the parties did not dispute the premise that two formulations produced the same results, and plaintiffs provided evidence that the range of equivalents did not ensnare the prior art, the court’s analysis was complete and the patent was found infringed.

The court also found that the patent was not obvious in light of the prior art. Only one reference of record, Maru, disclosed a hydrogel formulation. But Maru did not disclose the claimed excipients. At trial and in their briefing, defendants never described any combination of Maru with any other art that disclosed the excipients and did not provide any motivation to combine Maru with the other art. The court also noted that swapping ingredients in complex chemical formulations was not a simple or routine matter. Thus, defendants did not meet their burden. The court reasoned that combining Maru with the other art in the absence of guiding testimony or evidence would be pure speculation. Further, the secondary considerations favored a finding of non-obviousness.

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