Chapter §12.08 Improper Use of the Disclosure as Prior Art

• Jurisdiction: United States

§12.08 Improper Use of the Disclosure as Prior Art

In a controversial 2003 decision in Geneva Pharms., Inc. v. Glaxo-SmithKline PLC,⁸¹ the Federal Circuit most likely crossed over the fine line between proper and improper use of a patent's disclosure in a double patenting case.⁸² Patentee GlaxoSmithKline (GSK) owned a number of patents relating to the antibiotic clavulanic acid and its salts, and the use of same for treating bacterial infections in humans and animals. The patents were based on the discovery that clavulanic acid and the salts thereof possess the beneficial property of inhibiting b-lactamase, a compound that would otherwise deleteriously deactivate certain antibiotics such as amoxicillin.

Through corporate mergers GSK came to own two patents on similar technology involving clavulanic acid: U.S. Patent No. 4,529,720 (" '720 patent" or "Cole '720 patent")⁸³ as well as U.S. Patent No. 4,367,175 ("Fleming patent").⁸⁴ The '720 patent expired over two years after the Fleming patent expired,⁸⁵ setting the stage for a double patenting dispute. The claims of the two patents are compared below:

GSK's U.S. Patent No. 4,367,175 (The "Fleming patent") GSK's U.S. Patent No. 4,529,720 (" '720 patent" or "Cole '720 patent")

1. Potassium clavulanate [] having a molar extinction coefficient as determined in 0.1 M aqueous potassium hydroxide using ultraviolet light of wavelength 258 nm of about 17000. 1. A method of effecting â-lactamase inhibition in a human or animal in need thereof arising from a â-lactamase producing bacteria which comprises ad-ministering to said human or animal a â-lactamase inhibitory amount of clavulanic acid or a pharmaceutically acceptable salt thereof.⁸⁶

In a declaratory judgment lawsuit filed by generic drug manufacturer Geneva Pharms. Inc., a district court held the '720 patent invalid based on the Fleming patent.⁸⁷ The Federal Circuit affirmed the judgment that the '720 patent was invalid and clarified that the basis for invalidation was nonstatutory (obviousness-type) double patenting over the Fleming patent.

The controversy over the Federal Circuit's Geneva decision arises because claim 1 of the Fleming patent recites only the chemical compound potassium clavulanate (a particular salt of clavulanic acid) having certain properties. Claim 1 of the Fleming patent does not recite anything about use of the claimed compound to combat bacteria that produce â-lactamase. That use is the method recited in claim 1 of the '720 patent, however.

The Federal Circuit in Geneva first observed that the "earlier patent's [here, Fleming's] disclosure is not available to show nonstatutory double patenting."⁸⁸ But to perform its double patenting analysis, the court must "understand the scope of the compared claims." In the case at bar, the appellate court determined that claim 1 of the Fleming patent, "[s]tanding alone . . . does not adequately disclose the patentable bounds of the invention. Therefore, this court examines the specifications of both patents to ascertain any overlap in claim scope for the double patenting comparison."⁸⁹

The Federal Circuit concluded that a person of ordinary skill in the art, reviewing the disclosure of the Fleming patent, would recognize that the patent disclosed only one use for the claimed compound potassium clavulanate; namely, administration of the compound to patients to combat bacteria that produce â-lactamase. The Fleming patent disclosed no other use. "The '720 patent simply claims that use as a method." Because the " '720 patent claims nothing more than Fleming's disclosed utility as a method of using the Fleming compound . . . the claims of the Fleming and '720 patents are not patentably distinct."⁹⁰ Hence the '720 patent was invalid for nonstatutory double patenting over the Fleming patent.⁹¹

The problem with this analysis is that, as the Federal Circuit's quoted language seems to admit, the use of the claimed compound is "disclosed" in the written description of the Fleming patent but not recited in the Fleming claims. The Federal Circuit contended that its reliance on the Fleming patent's disclosure was for the purpose of determining the scope of the Fleming patent's claim 1. The contrary view is that rather than interpreting the claims, the Geneva court was improperly using the Fleming patent's disclosure as prior art.⁹² In other words, the Federal Circuit was essentially concluding that the method recited in claim 1 of the '720 patent would have been obvious in view of the compound recited in Fleming claim 1 in combination with the use of the compound as described in Fleming's written description. That is an obviousness analysis, not an obviousness-type double patenting analysis.

The Geneva controversy concerning proper use of a patent's disclosure in a double patenting analysis remains live. In 2008, the Federal Circuit relied on the Geneva rule to invalidate method claims for obviousness-type double patenting in Pfizer, Inc. v. Teva Pharm. USA, Inc. The Pfizer court contended that (as in Geneva) it was looking at the reference patent's disclosure of utility merely to determine the scope of its compound claim.⁹³

In 2010, the Federal Circuit expanded the controversial Geneva rule in Sun Pharm. Indus. Ltd. v. Eli Lilly and Co.⁹⁴ The essential distinction between the facts of the two cases was that in Sun Pharm., the reference patent disclosed not only the utility later claimed as a method in the patent invalidated for obviousness-type double patenting, but also disclosed a second, different utility. More specifically, Lilly's U.S. Patent No. 5,464,826 ('826 patent) claimed a method of treating cancer by using a compound called gemcitabine. Lilly also owned U.S. Patent No. 4,808,614 ('614 patent), which expired more than two years before the expiration date of the '826 patent. The '614 patent issued from a continuation-in-part application filed on the same day as the application that issued as the '826 patent.⁹⁵ The '614 patent claimed the compound gemcitabine and disclosed (but did not claim) its utilities including antiviral use as well as anti-cancer use.

The Federal Circuit invalidated the '826 method claims for obviousness-type double patenting over the composition claims of the '614 patent, announcing that "the holding of Geneva and Pfizer, that a 'claim to a method of using a composition is not patentably distinct from an earlier claim to the identical composition in a patent disclosing the identical use,' extends to any and all such uses disclosed in the specification of the earlier patent."⁹⁶

The Federal Circuit narrowly declined to rehear en banc the Sun Pharm. decision by a 5–4 vote.⁹⁷ Circuit Judge Newman issued an opinion dissenting from the court's denial of rehearing en banc, in which she was joined by Chief Judge Rader and Circuit Judges Lourie and Linn. Judge Newman's opinion first summarized the Sun panel's decision:

[T]he panel held the claims to the anticancer use to be invalid for double patenting because the anticancer use was mentioned (but not claimed) in the continuation-in-part specification that is not prior art, stating that "[t]he asserted claims of the later '826 patent simply

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