Patent Law - Substantially Equivalent Disclosure Sufficient to Satisfy Written Description Requirement for Non-Operative Features - Nalpropion Pharmaceuticals, Inc. v. Actavis Laboratories FL, Inc.

• Author: Stewart-Sloan, Charlotte

Patent Law--Substantially Equivalent Disclosure Sufficient to Satisfy Written Description Requirement for Non-Operative Features--Nalpropion Pharmaceuticals, Inc. v. Actavis Laboratories FL, Inc., 934 F.3d 1344 (Fed. Cir. 2019).

The statutes governing patents, 35 U.S.C. [section][section] 1-390, require all patents to include a specification containing a written description of the claimed invention. (1) The U.S. Court of Appeals for the Federal Circuit (CAFC) has construed this requirement to include a sub-condition mandating the written description of the claimed invention adequately convey to a person of ordinary skill in the art (POSITA) that the patent's inventors had possession of the claimed invention on the filing date of the patent application. (2) In Nalpropion Pharmaceuticals, Inc. v. Actavis Laboratories FL, Inc., (3) the CAFC considered whether a "substantially equivalent" disclosure was sufficient to convey such possession to a POSITA. (4) The court held such disclosure adequate for that purpose when only supporting a characteristic of a step of the method recited in the specified claim, and not any operative steps of that method. (5) The CAFC reasoned that, while substantially equivalent disclosure is not typically enough to satisfy the written description requirement, it should be sufficient for claim features other than operative claim steps when the factfinder has determined such substantial equivalence exists, and there is no challenge to the sufficiency of the associated operative claim steps' written description. (6)

On June 4, 2007, Orexigen Therapeutics (Orexigen), Nalpropion Pharmaceuticals' (Nalpropion) predecessor in interest of the patents at issue, filed a patent application directed to oral doses of sustained-release naltrexone--a medication suitable for treating conditions ranging from substance dependence to excess weight. (7) The application included examples describing the preparation of naltrexone oral doses, their dissolution profiles as measured by the USP Apparatus 1 Basket Method (Basket Method), and their efficacy for treating human patients. (8) The application also included a statement that in vitro release rates described are those determined by the USP Apparatus 2 Paddle Method at 100 rotations per minute in a dissolution medium of water at 37[degrees] C (Paddle Method). (9) On December 23, 2014, the patent application matured into a patent. (10) The issued patent included claims reciting in vitro dissolution profiles having ranges of naltrexone release as determined by the Paddle Method. (11) Data obtained using the Basket Method supports these claims. (12)

Litigation arose when Orexigen learned that Actavis had filed an Abbreviated New Drug Application (ANDA) seeking regulatory approval to sell a generic version of one of Orexigen's products. (13) Because the patent directed to oral doses of naltrexone exhibiting sustained-release behavior covered this product, Orexigen had a cause of action under 35 U.S.C. [section] 271(e)(2)(A) for patent infringement. (14) In response to Orexigen's infringement contentions, Actavis argued that the asserted claim was invalid due to a lack of written description support; namely, that the application did not convey to a POSITA that the inventors had possession of the claim's subject matter on the application's filing date. (15) Specifically, Actavis argued that this claim includes dissolution ranges that do not have adequate written description support because the inventors obtained the data allegedly providing such support with a technique different than that recited in the claim. (16)

When assessing the validity of the asserted claim, the Delaware District Court found that it was valid because Actavis had failed to prove by clear and convincing evidence that the claim lacked sufficient written description support. (17) The court credited expert testimony, which stated '195 Patent's specification conveyed to a POSITA that its inventors had possession of the claimed invention. (18) The Delaware District Court also found that the differences between the Basket Method and the Paddle Method were immaterial to this determination. (19) The CAFC agreed and held that the in vitro dissolution profile as determined by the Paddle Method is not an operative claim step, and thus is adequately supported by the substantially equivalent disclosure of in vitro dissolution profiles obtained by the Basket Method. (20)

Beginning with the Patent Act of 1790, each statute describing the preconditions for obtaining a patent has required inventors to provide a written description of the claimed invention. (21) Since at least 1967, the appellate courts having jurisdiction over patent matters have interpreted this requirement to mean that the inventors must show they invented the subject matter of the patent's claims. (22) In 1973, the Court of Customs and Patent Appeals (CCPA) further interpreted this requirement to also mean that the inventors must show they had possession of the claimed subject matter on the filing date of the application. (23) In the years since, the CAFC has explicitly expanded the written description requirement to encompass more than a mere statement of the claimed subject matter for certain types of inventions. (24) The CAFC has indicated that the extent of what must be included in the patent to satisfy the written description requirement varies depending on the predictability of the art in which the invention is made. (25) For inventions in unpredictable arts, the written description requirement can necessitate a description of one or more of the chemical, physical, and structural properties of claimed features of the invention. (26)

Prior to 2010, there was judicial and scholarly criticism of the CAFC's evolving interpretation of the written description requirement, with critics alleging it was too stringent and becoming increasingly conflated with the enablement requirement. (27) In response, in Ariad Pharmaceuticals, Inc. v. Eli Lilly & Co., the CAFC clarified that the written description requirement is standalone and separate from the enablement requirement. (28) The CAFC also held that whether a patent has satisfied the written description requirement should be assessed by performing a factual inquiry into the specification to determine if the inventors had possession of the claimed invention. (29) The CAFC explained that this inquiry should be performed in light of a POSITA's level of skill at the time the application was filed, and may be satisfied by constructive reduction to practice, actual reduction to practice, or experimental data showing possession. (30) The CAFC and the CCPA have allowed a wide variety of disclosure types to satisfy the written description requirement as long as the relevant disclosure conveys the required possession of the claimed invention to a POSITA. (31) For example, these courts have held that the written description requirement may be satisfied by language in a specification that is different from the language in the claim that it supports. (32) Additionally, these courts have held that portions of a patent that inherently, but not explicitly, describe a claim feature may satisfy the written description requirement for that claim feature. (33) Portions of the patent that merely make obvious the claimed features, however, have not satisfied the written description requirement. (34)

In Nalpropion Pharmaceuticals, Inc. v. Actavis Laboratories FL, Inc., the CAFC held disclosure that is substantially equivalent to a claim feature may provide adequate written description support if the claim feature is not an operative claim step. (35) First, the majority credited the Delaware District Court's factual finding that the substantially equivalent disclosure at issue would convey possession of the relevant non-operative claim feature to a POSITA. (36) The majority then acknowledged that, although substantially equivalent disclosure is typically insufficient to satisfy the written description requirement, the written description requirement for non-operative claim features should be assessed in a flexible and sensible manner. (37)

The dissent in Nalpropion criticized the majority's reasoning as overturning long-standing written description jurisprudence, laying out two supposed errors in the majority's analysis. (38) According to the dissent, the first error is that, when analyzing the asserted claim, the majority improperly differentiated between the dissolution profile as measured by the Paddle Method--a claim feature allegedly supported by substantially equivalent description--and its operative steps. (39) The dissent argued that this dissolution profile, even though non-operative, limits the scope of the asserted claim, and thus should be analyzed in the same manner as its other features. (40) The dissent further asserted that the majority erred by improperly allowing disclosure that merely makes a claim feature obvious to provide written description support for it. (41)

As both the majority and the dissent agree, the holding in Nalpropion breaks new ground by applying a looser standard to determine whether the information in a patent application establishes written description support for the claimed invention. (42) In its holding, the majority explicitly indicated that its decision was a "flexible, sensible interpretation" of the written description requirement and not one that was "rigid." (43) Although there are advantages associated with its reasoning, the majority fails to appreciate that its new rule weakens the protections that 35 U.S.C. [section] 112 affords to the public, thereby preventing inventors, and subsequently patent holders, from removing...