A U.S. federal district court judged the transitional phrase “consisting essentially of” to be indefinite in view of the Supreme Court’s ruling in Nautilus. Horizon Pharma Ireland Ltd. et al. v. Actavis Laboratories UT Inc., Case no. 1:14-cv-07992, in the U.S.D.C., District of New Jersey.

Background.    As we wrote about here, in its 2014 Nautilus decision, the Supreme Court reset the standard for indefiniteness under 35 U.S.C. § 112(b).  A claim term is indefinite if it fails to “inform those skilled in the art about the scope of the invention with reasonable certainty,” when read in light of the other claims, the specification and the prosecution history.  Nautilus Inc. v. Biosig Instruments, Inc.  The broad consensus in the patent community was that Nautilus could open up indefiniteness as a more viable defense.  The district court’s recent decision in Horizon will provide the Federal Circuit with an interesting test of the boundaries of this new indefiniteness standard.

Case at the District Court.  In a Hatch-Waxman case, Horizon asserted a number of patents against Actavis to prevent the launch of its generic version of PENNSAID (diclofenac sodium), a topical formulation used to treat osteoarthritis pain in the knees.  One of the patent claims included the transitional phrase “consisting essentially of.”  According to well-established Federal Circuit precedent, this phrase means that the invention necessarily includes the ingredients listed in the claim and no others, unless they “do not materially affect the basic and novel properties of the invention.”

At claim construction, Actavis argued that Nautilus should apply to determining “the basic and novel properties of the invention.”  One of the five “basic and novel properties of the invention” identified in the specification was “a better drying time,” and this was the focus of Actavis’s arguments.   The judge acknowledged that construction of the transitional phrase was proper where the “basic and novel properties of the invention” themselves were in dispute, and that the Nautilus standard should be applied.  He concluded that “a better drying time” was indefinite, finding that the two different methods described in the patent for measuring “drying time” produced different results and that a person of ordinary skill would not know under what standard to measure the “drying time.”  Thus, he concluded that the term “consisting essentially of” was found to be indefinite under the Nautilus standard, “due to the inability for a [skilled artisan] to have ‘reasonable certainty’ about what the basic and novel properties of the invention are.”

While the case is not yet ripe for appeal, one would expect Horizon to appeal this decision to the Federal Circuit once it is able.

Take away.  This case shows reaffirms the expectation that Nautilus would render patents more susceptible to indefiniteness challenges, and involves a relatively unique hook for such an indefiniteness attack.  ANDA-filers should carefully consider defenses based on § 112(b) when developing their Paragraph IV patent strategies.