Impax Laboratories Inc., AstraZeneca AB et al. V. Lannett Holdings Inc. et al.

Docket No. 2017-2020

June 28, 2018

Brief summary: DC finding that Impax’s (AZ’s) patents encompassing the migraine drug Zomig® were not invalid for obviousness affirmed (agreeing with the DC “that this case was close”).

Summary: Lannex appealed DC findings that the challenged claims of Impax’s US 6,760,237 and 7,220,767 relating to exclusive licensee Impax’s migraine drug Zomig® (zolmitriptan, a serotonin receptor agonist) were not shown to be invalid for anticipation (not appealed) or obviousness in view of several references. The DC also entered an injunction under § 271(e)(4) against Impax (Lannax has a pending ANDA for a generic version of Zomig®). The ‘237 claims are directed to zolmitriptan pharmaceutical formulations “suitable for intranasal administration” and “wherein the pH is in the range 4.5 to 5.5”, “5”, or “buffered”. The ‘767 claims claim a pH range of 3.5 to 5.5, or “less than 6.0”, and “buffered by a mixture of citric acid and disodium phosphate.” The FC panel reviewed the DC’s “conclusions of law (obviousness) de novo and its findings of fact for clear error” (Golden Blount, FC 2004; US Gypsum, FC 1986 (“definite and firm conviction that a mistake has been made”)). It also explained that “[a] party challenging the validity of a patent must establish invalidity by clear and convincing evidence” (Microsoft, US 2011; Procter & Gamble, FC 2009). Lannett argued that the DC’s nonobviousness conclusion was “based on an erroneous finding that the prior art taught away from nasal formualtions of zolmitriptan” (e.g., the DC “fail[ed] to consider the prior art ‘as a whole’” (Takeda, FC 2007)). Impax argued the DC correctly found no motivation or reasonable expectation in making the claimed nasal formulations. As an aside, in FN4 regarding the “Tepper & Rapoport” reference for which Lannex raised obviousness arguments found to be waived (FN4), the FC panel noted that “‘under development’ does not mean developed, with an expectation of success.” The FC panel considered the DC’s findings regarding the “Chauveau” reference which was found to “‘offer[] a laundry list of potential active ingredients,’ including ‘over twenty-five categories or examples of medications’” for “which the nasal route is preferred”, “in particular…zolmitriptan” and describe “example formulations” of a tryptamine “but not zolmitriptan.” The FC panel concluded that “Chauveau, as a whole, is not about intranasal formulations of zolmitriptan, which is barely mentioned” (“mentioned once, with no further mention in an example or claim”), but also that the DC properly viewed “the prior art as a whole” and “made additional findings beyond” that fact (e.g., expert opinion regarding zolmitriptan metabolites). The FC panel dismissed Lannett’s arguments against the DC’s metabolite-related conclusions as “attorney arguments” (Ferring, FC 2014 (rejecting a conclusory obviousness argument without evidentiary support)). Thus, “in view of the totality of the record evidence of the state of the prior art,” the FC panel found no clear error in the DC’s conclusions, including “that at the time, zolmitriptan’s known significant reliance on its active metabolite would have, on balance, dissuaded a person of skill in the art from making nasal formulations” (Winner Int’l, FC 2000; Intendis, FC 2016). The FC panel found no error with the DC that the $130 million agreement between Impax and AstraZeneca was significant secondary evidence, and that there was a nexus between the agreement and the disputed patents. The FC panel also wrote that it agreed with the DC “that this case was close” but “defer[ed] to the [DC] in its fact finding” and was “especially persuaded by the testimony of” Impax’s expert (e.g., “‘absolutely counterintuitive’ to make an intranasal formulation”). Thus, the DC decision was affirmed.

This entry was posted in Generics / ANDA, Obviousness, Obviousness-Teaching Away. Bookmark the permalink.

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