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The Enablement Requirement of § 102, Unlike § 112, Does Not Require Proof of Efficacy or Utility

November 20, 2006

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Last Month at the Federal Circuit - December 2006

Judges: Rader (concurring-in-part), Schall (author), Prost

[Appealed from: D. Del., Judge Farnan]

In Impax Laboratories, Inc. v. Aventis Pharmaceuticals Inc., No. 05-1313 (Fed. Cir. Nov. 20, 2006), the Federal Circuit affirmed a district court’s finding of failure to prove inequitable conduct based on omission of alleged material information during prosecution, holding U.S. Patent No. 5,527,814 (“the ’814 patent”) enforceable. On the issue of invalidity, the Federal Circuit vacated the district court’s decision that one prior art reference did not anticipate the claims because it was not enabled, and remanded for further proceedings using the proper legal standard enunciated by the Court. In discussing the proper legal standard, the Court reiterated that the enablement requirement of 35 U.S.C. § 102 differs from the enablement requirement of 35 U.S.C. § 112. The Court explained that enablement under § 102 does not require utility, or proof of efficacy, unlike enablement under § 112.

Aventis Pharmaceuticals Inc. (“Aventis”) is the owner of the ’814 patent, directed to methods of treating a mammal with amyotrophic lateral sclerosis (“ALS”), commonly known as Lou Gehrig’s disease,with riluzole. Impax Laboratories, Inc. (“Impax”), a generic drug manufacturer, filed suit for a DJ in district court that it did not infringe the ’814 patent under 35 U.S.C. § 217(e)(2) by filing an ANDA. In its ANDA, Impax sought approval from the FDA for the sale and/or manufacture of riluzole tablets for the treatment of ALS. Impax alleged in its suit that the ’814 patent was unenforceable and invalid. Impax has since conceded that its ANDA product infringes claims 1, 4, and 5 of the ’814 patent.

Claims 1-5 of the ’814 patent were at issue in the case. Claim 1 is the only independent claim and recites “[a] method for treating a mammal with amyotrophic lateral sclerosis, comprising the step of administering to said mammal in recognized need of said treatment an effective amount of 2-amino-6- (trifluoromethoxy)benzothiazole or a pharmaceutically acceptable salt thereof.” Claims 2-5 add limitations to the forms of ALS treated or dosages of riluzole administered.

In the district court, Impax’s allegations concerning inequitable conduct centered on the fact that Aventis had conducted comparative tests of eight different compounds, including riluzole (“tested compounds”), in animal models to evaluate the effectiveness of each compound for treating ALS. Three different criteria were used for the evaluation. Only riluzole was demonstrated to be effective by all three criteria.

During prosecution, Aventis addressed an obviousness rejection based on U.S. Patent No. 5,236,940 (“the ’940 patent”) by providing the Examiner with the comparative test data for riluzole and two of the tested compounds, which were disclosed in the ’940 patent. Aventis asserted that those test results showed unexpected results for riluzole, which were not predictable from the prior art. Aventis did not provide the test results for the other tested compounds, which were not disclosed in the ’940 patent.

Impax alleged that Aventis’s withholding of comparative test data for certain of the tested compounds was material because the withheld test results were inconsistent with an argument advanced by Aventis in support of patentability during prosecution. Impax asserted that the results for the other tested compounds were superior to those provided to the Examiner, and thus did not support Aventis’s claim of unexpected results for riluzole.

The district court disagreed, finding the withheld test results not material and also finding no intent to deceive. Thus, the district court determined that there was no inequitable conduct.

In affirming the district court’s determination of no inequitable conduct, the Federal Circuit, along the lines of the district court, found that the withheld test data were not material because (1) the withheld test data did not produce results that indicated effectiveness in treating ALS; (2) the withheld test data were not inconsistent with the representations to the Examiner concerning riluzole; and (3) there was no evidence that a reasonable examiner would have considered the withheld test data important in deciding whether to allow the patent application. And, in affirming the district court’s finding of lack of intent to deceive, the Federal Circuit decided that failure to disclose test results for compounds that were irrelevant to distinguishing over the cited patent was not enough, on its own, to establish an intent to deceive. Thus, the Federal Circuit affirmed the district court’s determination of no inequitable conduct.

The Court next addressed the district court’s decision that the ’814 patent was not anticipated by the ’940 patent or by its priority application, French Application No. 2,640,624 (“the ’624 application”). The ’940 patent is directed to a class of compounds of formula I, which encompasses hundreds of compounds. The ’940 patent specifies that riluzole is a compound of formula I, but is not part of the invention because it is not new. The ’940 patent also provides that “[t]he compounds of formula (I) and their salts . . . are useful in the treatment of medical conditions associated with the effects of glutamate in which it is desirable to inhibit such effects at least partially. They are . . . useful in the treatment and prevention of . . . neurological conditions in which glutamate may be implicated, such as . . . amyotrophic lateral sclerosis . . . .” The disclosure of the ’624 application is similar to that of the ’940 patent, except that it does not exempt riluzole as a claimed compound—in fact, it does not mention riluzole at all.

In the district court, Impax alleged that the ’940 patent and ’624 application anticipated the claims of the ’814 patent because every limitation of the claims was disclosed in the prior art. The district court found that the ’940 patent formula includedriluzole, but determined that the disclosure did not enable the use of riluzole for treating ALS. According to the district court, “formula I entails such a large number of compounds . . . [that] one of ordinary skill in the art would not have recognized that riluzole was effective in treating ALS without additional detail or guidance that is not found in the disclosure of the ’940 patent.” Slip op. at 21 (emphasis in original). The district court concluded that the ’940 patent, and for similar reasons, the ’624 application, were not enabled, and therefore neither reference anticipated the claims of the ’814 patent.

Focusing on the district court’s pronouncement that the ’940 patent was not enabled because it did not disclose “that riluzole was effective in treating ALS,” the Federal Circuit reiterated the proper legal standard by which to evaluate the enablement requirement of § 102. The Court explained that “[i]n order to be anticipating, a prior art reference must be enabling so that the claimed subject matter may be made or used by one skilled in the art. . . . The enablement requirement for prior art to anticipate under section 102 does not require utility, unlike the enablement requirement for patents under section 112. . . . [A]nticipation does not require actual performance of suggestions in a disclosure. Rather, anticipation only requires that those suggestions be enabled to one of skill in the art.” Id. at 24-26 (citations omitted). The Court further noted that “[a] reference is no less anticipatory if, after disclosing the invention, the reference then disparages it. Thus, the question of whether a reference ‘teaches away’ from the invention is inapplicable to an anticipation analysis.” Id. at 26.

After setting forth the proper legal standard for evaluating whether an anticipatory reference is enabled, the Court vacated the district court’s decision regarding the ’940 patent, holding that the wrong standard for enablement had been applied. “While the ’940 patent includes riluzole as a formula I compound, suggests that formula I compounds may be used to treat ALS, and provides some dosage information, the district court found that the ’940 patent did not anticipate the ’814 patent because the disclosure of the ’940 patent was not enabling at least in part because there was no evidence that it would be ‘effective.’” Id. at 27. Since the “effectiveness” of the prior art is not relevant, the Federal Circuit remanded the case to the district court to determine whether the ’940 patent is enabled under the proper legal standard.

The Federal Circuit also addressed the district court’s finding that the ’624 application was not enabled. Unlike the ’940 patent, the ’624 application does not mention riluzole by name. Accordingly, the Federal Circuit affirmed the district court’s finding, stating that “riluzole is just one of hundreds of compounds included in formula I. . . . Here, with the large number of compounds included in formula I and no specific identification of riluzole by the ’624 application, the ’624 application does not disclose riluzole, and therefore, cannot enable treatment of ALS with riluzole. The ’624 application cannot anticipate any of claims 1-5 of the ’814 patent.” Id. at 28. Accordingly, the Federal Circuit remanded the case for further proceedings.