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35 U.S.C. § 121's Shield Applies to Formal PTO Restriction Requirements

November 24, 2003

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Last Month at the Federal Circuit - December 2003

Judges: Rader (author), Mayer, and Bryson

In Geneva Pharmaceuticals, Inc. v. GlaxoSmithKline PLC, No. 02-1439 (Fed. Cir. Nov. 21, 2003), the Federal Circuit affirmed a district court's judgment invalidating the claims of several patents for nonstatutory double patenting.

GlaxoSmithKline, PLC et al. ("GSK") own the eight patents-in-suit, which all originate from the same parent application, U.S. Patent Application No. 05/569,007 ("the '007 application"). The eight patents-in-suit can be divided into two groups: those patents that issued in 2000-2001 ("the 2000/01 patents"), and those patents that issued in 1985 ("the 1985 patents"), which include U.S. Patent Nos. 4,525,352 ("the '352 patent"); 4,529,720 ("the '720 patent"); and 4,560,552 ("the '552 patent").

The patents-in-suit relate to the antibiotic clavulanic acid and its salts. Clavulanic acid retains an ability to protect a variety of antibiotics against a number of enzymes produced by bacteria, such as ß-lactamase, that render antibiotics useless. Specifically, the patents-insuit claim clavulanic acid in combination with antibiotics like amoxicillin or penicillin, and methods of using clavulanic acid and its salts to inhibit ß-lactamase.

Geneva Pharmaceuticals, Inc. filed DJ suits against GSK challenging the validity of the 2000/01 and 1985 patents. Upon motions for SJ, the district court held the 2000/01 patents invalid for nonstatutory double patenting over the '720 patent. The district court ruled that 35 U.S.C. § 121 did not shield the 2000/01 patents against invalidity over the '720 patent. Subsequently, after a bench trial, the district court invalidated the 1985 patents on nonstatutory double-patenting grounds over two expired GSK patents, the Crowley patent and the Fleming patent.

On appeal, the Federal Circuit affirmed the district court and held that § 121 did not shield the 2000/01 patents from double-patenting invalidity over the '720 patent for two reasons. First, the Court determined that the 2000/01 patents and the '720 patents did not trace their lineage back to a common parent, a requirement to obtain § 121 protection, because the method of use claims, which appear in the '720 patent, were never pending in the original '007 application. To protect a patent from a doublepatenting rejection, § 121 requires that the claims later sought to be shielded must appear in a parent application before a restriction requirement is issued. According to the Court, section 121 does not shield claims merely because the parent application provides some support for claims that are first entered in subsequent related applications. In this case, the '720 patent's claims never appeared in the original '007 application. Because of this, the '720 patent could not have been a formal divisional of the '007 application so that § 121 would prevent the '720 patent from erecting a nonstatutory double-patenting bar against the 2000/01 patents.

Second, even assuming nonpending claims could be restricted, the Court ruled that the prosecution history in this case did not clearly document a restriction requirement, another prerequisite for § 121's statutory shield. The Court noted that the Examiner issued no document referring anywhere to "restriction." GSK argued that an interview summary evidenced a proper restriction requirement. The Court, however, found that the interview summary did not clearly set forth the subject matter and the specific claims that the PTO considered patentably distinct. Section 121 only shields claims against a double-patenting challenge if it clearly sets forth the line of demarcation between the independent and distinct inventions that prompted the restriction requirement. Because the interview summary did not clearly refer to groups of claims that the Examiner considered patentably distinct, GSK did not meet its burden in showing that the record provided a clear demarcation of the allegedly restricted subject matter.

The Court also affirmed the district court's judgment invalidating on nonstatutory doublepatenting grounds two of the 1985 patents, the '352 and '552 patents, in light of the Crowley patent. The Court noted that the '352 and '552 patent claims recite limitations that are either broader than or obvious variants of corresponding limitations in the Crowley claim. The Crowley patent claims pharmaceutical compositions containing "20 mg to 500 mg of potassium clavulanate [a salt of clavulanic acid]" in combination with amoxicillin, whereas the '352 and '552 patents claim pharmaceutical compositions containing a "synergistically effective amount" of clavulanic acid in combination with amoxicillin and penicillin, respectively. GSK argued that the claim limitation "synergistically effective amount" was a point of patentable distinction between the '352 and '552 patents and the Crowley patent. The Court, however, disagreed and construed the term "synergistically effective amount" to mean any amount that is synergistic against any bacteria. Because this amount encompassed a substantial part of the subject matter of the Crowley claim—namely, the "20 mg to 500 mg" range—the Court found the '352 and '552 patent claims patentably indistinct from Crowley and, thus, invalid.

Finally, the Court affirmed the district court's judgment invalidating GSK's remaining 1985 patent, the '720 patent, on nonstatutory double-patenting grounds over the Fleming patent. The Fleming patent claims a compound, potassium clavulanate, for which the written description discloses the single use of inhibiting ß-lactamase. The '720 patent claims that use as a method. The Court held that the Fleming and '720 patents are not patentably distinct because 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.