Seed Intellectual Property Law Group PLLC

“An Important Ruling on Double Patenting,” by Qing (Becky) Lin, Ph.D.

On July 28, the U.S. Court of Appeals for the Federal Circuit in Sun Pharmaceutical Indus. Ltd. v. Eli Lilly Co., 611 F.3d 1381 (Fed. Cir. 2010), issued an important ruling on double patenting. The double patenting doctrine precludes an applicant from obtaining more than one valid patent for either the same invention (“statutory double patenting”) or for an obvious variation of the invention (“obviousness-type double patenting”). The purpose of both types of double patenting is to prevent an unjust patent-term extension resulting from a later patent. While acknowledging the general rule that the specification of an earlier patent is not available to show double patenting against a later patent, the court nevertheless held that the entire specification of an earlier patent must be examined to construe claims in the earlier patent during double-patenting analysis. On Nov. 1, the court declined to rehear this case by a 5-4 majority. 625 F.3d 719 (Fed. Cir. 2010).

Sun resulted from an appeal by Eli Lilly from a district court decision that found certain claims invalid for obviousness-type double patenting over an earlier patent. The earlier patent discloses gemcitabine and its antiviral and anti-tumor activities but only claims the compound gemcitabine and its use for treating herpes viral infections. The later patent claims a method of treating cancer using gemcitabine.

The Federal Circuit held the claims in the later patent invalid for obviousness-type double patenting over a compound claim directed to gemcitabine of the earlier patent in view of the disclosure of gemcitabine’s anti-tumor activity in the earlier patent. It analogized this case to Geneva Pharmaceuticals Inc. v. GlaxoSmithKline PLC, 349 F.3d 1373 (Fed. Cir. 2003), and Pfizer Inc. v. Teva Pharmaceuticals USA Inc., 518 F.3d 1353 (Fed. Cir. 2008), in both of which the Federal Circuit rendered the same double-patenting decision. Although acknowledging the general rule that obviousness-type double patenting cannot rely on an earlier patent’s specification, the Federal Circuit stated that the entire specification of the earlier patent must be examined to construe the claims of the earlier patent during double-patenting analysis. It further elaborated that, because a claim to a compound standing alone did not adequately disclose the patentable bounds of the invention, in examining the specification of the earlier patent, the court must consider the compound’s disclosed utility.

Because it is the claims, not the specification, that define an invention, in general, an obviousness-type double-patenting analysis compares a claim in an earlier patent to a claim in a later patent. Ortho Pharmaceutical Co. v. Smith, 959 F.2d 936, 943 (Fed. Cir. 1992). A court first construes the claim in the earlier and later patents and determines the differences, and then decides whether those differences render the claims patentably distinct. A later claim is not patentably distinct from an earlier claim and thus invalid for double patenting if it is obvious from, or anticipated by, the earlier claim.

EXPANSION OF CIRCUMSTANCES
Sun, along with Geneva and Pfizer, indicates expansion of circumstances under which double patenting may be found in a patent claiming a pharmaceutical use of a compound in view of an earlier patent claiming the compound if the earlier patent discloses that the compound is useful for such pharmaceutical use. In Geneva, the earlier patent claimed a compound and disclosed a single use of the compound. The Federal Circuit found a later claim directed to the same single use invalid for double patenting. In Pfizer, the Federal Circuit extended the double-patenting holding to situations in which the earlier patent claims compositions and discloses multiple related uses of active compounds encompassed by the compositions. In Sun, the Federal Circuit further extended the double-patenting holding to the case in which the earlier patent claims a compound and discloses a use of the compound that is unrelated to the use claimed in the earlier patent.

With the expansion of the circumstances under which double-patenting invalidation might be found, the Federal Circuit shifted its emphasis regarding the basis for such findings. In Geneva, the primary rationale was that, because the single use claimed in the later patent was necessary to the patentability of the compound claimed in the earlier patent, it constituted an essential part of a single invention. In Pfizer, due to multiple uses disclosed in earlier patents, the primary rationale for the double-patenting finding in Geneva was not applicable. Instead, the Federal Circuit cited Geneva to support its examination of the specification in determining the claim scope during the double-patenting analysis. In Sun, the Federal Circuit further stated that the entire specification of the earlier patent must be examined to construe claims for the double-patenting analysis.

The emphasis of examining the entire specification of the earlier patent for double-patenting analysis in Sun heightened the tension between the general rule that double-patenting analysis may not rely on the specification of an earlier patent and the seemingly contradictory exceptions to this rule. According to previously developed exceptions to the general rule, the specification may be used to determine whether a claim merely defines an obvious variation of what is earlier disclosed and claimed, to learn the meaning of claim terms, and to interpret the coverage of a claim. In re Basell Poliolefine Italia SpA, 547 F.3d 1371, 1378 (Fed. Cir. 2008).

Because the question of whether a claim merely defines an obvious variation of earlier claimed subject matter substantially overlaps with the ultimate question for double-patenting determination, reviewing the specification of the earlier patent to answer the former question amounts to a broad exception, if not a direct contradiction, to the general rule. To reconcile the seemingly contradictory notions, the Federal Circuit stated that “use of the disclosure is not in contravention of the cases forbidding its use as prior art,…since only the disclosure of the invention claimed in the patent may be examined.” Id. at 1379. However, this attempt at reconciliation seems to have been largely defeated by the statement in Sun that the entire specification of an earlier patent must be examined.

It is unclear whether the double-patenting analysis of Sun will be limited to cases involving patents claiming compounds and their uses only or if it is more broadly applicable. On one hand, the statement in Sun that the entire specification must be examined to construe claim terms can be easily applied to other cases. On the other hand, the double-patenting holding in Sun could primarily result from policy considerations specifically relevant to cases involving compounds and their uses. In all three recent cases in this area, the Federal Circuit quoted In re Byck, 48 F.2d 665, 666 (CCPA 1931): “It would shock one’s sense of justice if an inventor could receive a patent upon a composition of matter, setting out at length in the specification the useful purposes of such composition,…and then prevent the public from making any beneficial use of such product by securing patents upon each of the uses to which it may be adapted.”

In view of Sun, a patent applicant should take precautions to avoid double patenting. One way to do so is to eliminate disclosures in one application related to the subject matter claimed in another application. For example, if Eli Lilly had not included the description of gemcitabine’s anti-tumor activity in the earlier patent, its later claims directed to using gemcitabine in treating cancer would not have been invalidated for double patenting. In other cases in which earlier and later applications descend from a single application and have an identical specification, it may be desirable to present both compound claims and claims directed to methods of using the compounds in the earlier application. If an examiner requests restriction between the compound and method claims, the applicant may rely on 35 U.S.C. 121 to prevent the earlier application from being used against the later application. Otherwise, the applicant may pursue both the compound and method claims in the earlier application.

In summary, the Federal Circuit stated in Sun that the entire specification must be examined to construe an earlier claim for double-patenting determination. Relying on the disclosure of uses of a compound in an earlier patent, the Federal Circuit held a claim directed to one of the uses invalid for double patenting over an earlier claim directed to the compound. In view of Sun, it is prudent for a patent applicant to eliminate disclosures in one application related to the subject matter claimed in another application.

Qing (Becky) Lin (BeckyL@SeedIP.com) is a partner at Seed Intellectual Property Law Group in Seattle. Her practice focuses on biotechnology and pharmaceutical patent prosecution.